FLOORING WORK - 2



FLOORING WORK

14.38. SPECIFICATIONS FOR TIMBER FLOORS

14.38.1. General - Timber floors are provided in auditoria, gymnasia, dancing halls, squash courts, public balconies, galleries, skating rinks, etc, for noise retardant floor finish and in hilly areas as thermal insulating floor finish.  These floors may also be used in timber framed construction to serve as structural floors.

14.38.2. Materials - The species of timber recommended for floor board shall be as given in Annex B   with their percentage of indentation for hardness, taking teak as 100. 

a) Species of timber selected for girders, binders and projecting joists shall be as given below

1) For spans of 12 m and greater, all the species of Group ‘Super’ specified in IS: 3629-1986.

2) For spans greater than 6 m but less than 12 m, all the species of Group ‘Standard’ specified in IS: 3629 -1986.

3) For spans up to and including 6 m, all the species of Group ‘Ordinary’ specified in IS: 3629 - 1986.

b)  Timber selected for construction of floor boards and supporting members shall conform to the following;

1) The species should be non-refractory; 2) The thickness of boards shall be from 25 to 40 mm.

3) For joists, binders and girders the modulus of elasticity should be not less than 5.625 N / mm2 and the extreme fibre stress should be not less than 8.5 N / mm2.

Nails conform to IS: 723-1972 and diamond pointed.

All timber shall be seasoned as per IS: 1141-1993 and preserved as per IS: 401-1982. If water preservatives are used, it shall be seasoned a second time.  Proper anti-termite measures shall be adopted for use in buildings.  Damp-proofing, where necessary, shall be done described in Section 10 of KBS.

14.38.3. Types of timber floors - Timber floors are generally of the following types

  1. Single joisted floors having bridge joist only ;
  2. Double joisted floors having bridge joists supported on binders ;
  3. Triple joisted floors having bridging joists supported on binders and framed into girders ;
  4. Solid timber floors/wood block floor ; and
  5. Purpose made floor / parquet floors, etc.

14.38.4. Construction 

14.38.4.1. Single joisted timber floor - This type is constructed on ground floor, generally in theatres where dance and drama performances are regularly held.  Also they are suited for buildings in hilly regions and damp areas. The construction sequence is as below

a) Clear the site of vegetation, etc.

b) Honey-combed dwarf walls are built, preferably half brick thick at intervals of 2 m to a suitable height.

c) In case of basement floors, particularly, for theatres, the space between the dwarf walls may be filled with dry sand up to DPC level as shown in Fig. 21

d) Over the DPC on dwarf walls longitudinally wooden members, or wall plates, are solidly bedded level by means of suitable lime or cement mortar.

e) The timber floor joists (bridging joists) are mailed to these wall places see Fig.22

f) Proper ventilation should be ensured to prevent dry rot of timber.

g) There should be a gap between the underside of every joists/girder of the ground floor and top surface of sand filling or site concrete.

h) Wall plates and ends of joists should not be built into the side walls.  Spacing of joists may be between 300 to 450 mm.

i) On properly fixed joists, wooden boards 25-30 mm thick, 100-150 mm wide and 3 m long generally widened by tongued and grooved joints shall be laid and fixed by screw/nails.

j) The surface of the boards are leveled and rubbed smooth.

Timber floors for upper floors. The details are as in Fig.  22

14.38.4.2. Double joisted timber floor  - These are used for longer spans between 3.5 m and 5 m.  To make it more sound proof the construction procedure is as follows.

a) The bridging joists, instead of spanning from wall to wall, are supported by larger horizontal members (binders) at suitable intervals, between 2 m to 5 m in the shorter direction of the room.

b) Floor boards are supported on bridging joists.

c) The binders shall not be placed over door window openings unless designed as lintels.  Ends of binders should not touch masonry.

d) Ceilings may be fixed to the bottom of the binders.

14.38.4.3. Triple joisted timber floor -  The details are as in BIS

14.38.4.4. Solid timber floors - The details are as in Fig. 23.

14.38.4.5. Purpose–made floors - These are not generally made solid; they are primarily hollow floors.  They are named according to purpose they serve, namely, Skating-rink floor, Badminton floor, Squash floor, etc.  Some details are as in Fig. 24.

14.38.5. Timber floor boards - The timber floor boards, 25 to 30 mm thick, 100 to 150 mm wide and 2 to 3 m long are joined by widening joints listed in order of efficiency as given below (see Fig. 25)

Fig 21 Basement timber floor

Fig 22 Single joisted upper floor

Fig 23 Room showing sub-flooring of cement concrete and wooden fillets

Fig 24 Typical detail of fixing of floor joist and timber floor

Fig 25 Different types of joints in timber flooring boards

14.39. SPECIFICATIONS FOR LYING OF FLEXIBLE PVC SHEET AND THE FLOORING

14.39.1. PVC flooring material manufactured in different patterns to match and suit any decorating scheme is normally used for covering floors from decorative point of view in residential and office buildings and also in railway coaches.  The material gives a resilient and non-porous surface which can be easily cleaned with a wet cloth as dust and grime do not penetrate the surface.  Since a burning cigarette will damage the neat surface of the PVC sheet, special care should be taken to prevent burning cigarette stumps to come in contact with the PVC flooring material.

The performance of the PVC flooring depends very much on the preparatory treatment given to the sub-floor, the selection of an appropriate adhesive for fixing, the care being taken in laying the flooring material on the sub-floor and the maintenance of the finished floor.  Special care should be taken in preparing the sub-floor and making the base permanently dry so that the PVC flooring after laid will not be affected by absorption of moisture by the sub-floor.  Hot sealing of joints between adjacent PVC flooring to prevent creeping of water through the joints is under study as the method is likely to increase the life of the floor.

For the purpose of this specification, the following definitions shall apply.

Flooring – The resilient PVC flexible sheet or tile or PVC (vinyl) asbestos tile flooring material.

Screed topping – A bed of cement mortar (1 cement: 3 sand) applied to a sub-floor and brought to a defined level.

Sub-floor – The surface on which the flooring is to be laid.

Underlay – A layer of sheet material or in situ filling on the sub-floor or the screed topping to provide a smooth level surface to receive the flooring.  Underlay may be in the form of sheet underlay or trowelled underlay.

Material: Flooring – The flooring shall comply with the requirements specified in IS: 3461-1966 and IS: 3462-1966.The thickness of the flooring shall depend on the service conditions.

Underlay - Underlay shall be compatible with the flooring and adhesive to be used.  Underlay for use on concrete sub-floor shall be the screed topping. Underlay for use on uneven and rough wood sub-floor shall be 3 mm thick BWR grade plywood conforming to IS: 303-1960.

Adhesives – Rubber based adhesives are suitable for fixing PVC flooring over concrete, wooden and metal sub-floors.  PVA based adhesives may be used for concrete and wooden sub-floors.  PVA based adhesives are not suitable for metallic surfaces and also for locations where there is constant spillage of water.

Necessary information - For efficient planning and execution of the work, the following points shall be taken into account:

 Area of floor; (a)Type of sub-floor and underlay; (b)Type and thickness of screened bed, if any; (c)Curing and drying time for concrete bed and screed;(d)Damp-proofing treatment provided; (e)Evenness of the finished floor;(f)Type, quality and thickness of flooring;(g)Services passing through flooring; (h)Treatment of skirting;(i)Treatment of junction with adjacent flooring;(j)Type of ventilation provided to wood sub-floor;(k)Any dressing or polishing required; and (l)Protection of completed flooring.

Preparation of sub-floors

14.39.1.1. The PVC flooring gives good service when laid on a firm base.  Evaporation of moisture from the sub-floor cannot take place once the PVC flooring is laid.  Therefore, it is important that sub-floor and underlay should be thoroughly dry before laying the PVC flooring.  An irregular sub-floor surface creates poor adhesion between the sub-floor and the PVC flooring; therefore, the sub-floor surface should be leveled.  Recommended treatments for different sub-floors shall be as specified.

14.39.1.2. Timber

In the case of new construction, seasoned and treated timber shall be used and shall preferably be of tongued and grooved boarding.  Boards should be narrow and of equal width.  Boards of very unequal width have various degrees of shrinkage.  Before fixing the PVC flooring, all nail heads on the timber sub-floor shall be punched down, irregularities planed off and holes filled with suitable fillers.  High spots on the timber sub-floor produce spots of rapid wear in the flooring.  In case of suspended timber floor which is properly designed and is well ventilated, covering the floor with PVC flooring does not result in the growth of fungus.  In the case of badly ventilated timber floor, any impervious covering like the PVC flooring reduces the already deficient ventilation and allows the moisture content of the timber to increase sufficiently to encourage fungal attack.  Because of the risk of fungal attack, wood blocks and boarded floor over concrete laid on the ground shall not be covered with PVC flooring unless an efficient damp-proof membrane in the concrete below the blocks has been provided.

In the case of an existing timber floor, covered with boarding when it is not possible to obtain an even surface or in cases of fungal attack, the use of diagonal boarding is recommended, after removing and replacing some of the badly affected boarding and filling in cracks with plastic wood or similar filler and after disinfecting the floor.  Alternatively, plywood topping in accordance with 3.2.1.2 on the existing boarding also gives an even surface.  It is important to see that floor is well ventilated.

14.39.1.3. Concrete

A concrete sub-floor on the ground intended for fixing PVC flooring shall contain an effective damp-proof course, shall be finished with a trowel and shall be left long enough for the concrete above the damp-proof course to dry out.  The damp-proofing treatment shall be given in accordance with the approved methods.  

The concrete sub-floor shall be laid in two layers.  The top of the lower layer of concrete shall be painted with two coats of bitumen, conforming to IS: 1580-1969 applied at the rate of 1.5 KG/M2.  The surface of the lower layer shall be finished smooth while laying the concrete so that bitumen can be applied uniformly.  The bitumen shall be applied after the concrete has set and is sufficiently hard. 

Bitumen felt conforming to IS: 1322-1967 shall be sandwiched in the sub-floor concrete laid in two layers.  The surface of the lower layer shall be finished smooth while laying the concrete so as to provide an even surface and thus prevent damage to the surface of the bitumen felt water proofing membrane.

Where it is expected that the dampness may find its way from the surrounding walls, the same shall also be effectively damp-proofed up to at least 150 mm above the level of the sub-floor and the damp-proof treatment below the floor shall be extended over the walls.  The basement floor shall be damp-proofed according to the recommendations of IS: 1609-1966.

Before PVC flooring is laid, ample time shall be allowed for the water to dry completely from the concrete floor.  It is difficult to specify the period required as it depends on weather and on the quality and thickness of the concrete, but a period of at least 4 to 8 weeks shall be allowed for drying under normal conditions.  The time may be reduced if the building is well ventilated.

In new work, the finish required for laying PVC flooring shall be produced with a trowel on a screed applied to the sub-floor concrete.  The finish may, however, be produced on the sub-floor concrete itself by using a power-float.  With old concrete, the surface shall be scrapped free of all foreign material and swept clean.  The surface shall be kept wet for 24 hours by sprinkling water and then screed topping of 3 mm thickness shall be provided over the concrete.  If the existing concrete surface is even, the sub-floor shall be cleaned and made free of grease, oil, paint and other deleterious materials.  A separate layer of screed topping may not be necessary in this case.

14.39.1.4. Metal floors –  Metal floors shall be made free from rust and scale by chipping and/or vigorous wire brushing and cleaning.  Metal floors shall be free from undulations due to welded joints.  The welded joints which may come in contact with the PVC flooring shall be ground smooth.  Paint and grease shall be removed by caustic soda washing followed by thorough rinsing with fresh water.  Suitable putty compatible with the adhesive shall be used for filling metal surfaces to obtain a smooth, uniform and free from indentations and protrusions.

14.39.2. Laying and fixing of PVC flooring - Prior to laying, the flooring shall be brought to the temperature of the area in which it is to be laid by stacking in a suitable manner within or near the laying area for a period of about 24 hours.

Where air-conditioning is installed, the flooring shall not be laid on the sub-floor until the conditioning units have been in operation for at least seven days.  During this period the temperature shall neither fall below 20oC nor exceed 30oC.  These conditions shall be maintained during laying and for 48 hours thereafter.

Before commencing the laying operations, the sub-floor shall be examined for evenness and dryness.  The sub-floor shall then be cleaned with a dry cloth.  The PVC flooring shall not be laid on a sub-floor unless the sub-floor is perfectly dry.  Methods of testing for dryness are given in 14.39.9. 

The layout of the PVC flooring on the sub-floor to be covered should be marked with guidelines.  The PVC flooring shall be first laid for trial without using the adhesive according to the required layout.

The adhesive shall be applied by using a notched trowel (see fig. Below) to the sub-floor and to the back side of the PVC sheet or tile flooring.  When set sufficiently for laying, the adhesive will be tacky to the touch, but will not mark the fingers.  In general, the adhesive will require about half an hour for setting, it should not be left after setting for too long a period as the adhesive properties will be lost owing to dust films and other causes. 

Care should be taken while laying the flooring under high humidity conditions so that condensation does not take place on the surface of the adhesive.  It is preferable to avoid laying under high humidity conditions.

The area of adhesive to be spread at one time on the sub-floor depends entirely upon local circumstances.  In case of a small room adhesive may be spread over the entire area but relatively small areas should be treated in a larger room.

When the adhesive is just tack free, the PVC flooring sheet shall be carefully taken and placed in position from one end onwards slowly so that the air will be completely squeezed out between the sheet and the background surface.  After laying the sheet in position, it shall be pressed with suitable roller to develop proper contact with the sub-floor.  The next sheet with its back side applied with the adhesive shall be laid edge to edge with the sheet already laid and fixed in exactly the same manner as the first sheet was fixed.  The sheets shall be laid edge to edge so that there is minimum gap between joints.

The alignment should be checked after laying of each row of sheet is completed.  If the alignment is not perfect, the sheets may be trimmed by using a straight edge.

The tiles shall be fixed in exactly the same manner as for the sheets.  It is preferable to start laying of the tiles from the centre of the area.  Care should be taken that the tiles are laid close to each other with minimum gap between joints.  The tiles should always be lowered in position and pressed firmly on to the adhesive.  Care should be taken not to slide them as this may result in adhesive being squeezed up between the joints.  PVC tiles after laying shall be rolled with a light wooden roller weighing about 5 kg to ensure full contact with the underlay.  Any undulations noticed on the PVC surface shall be rectified by removing and relaying the tiles after thorough cleaning of the underside of the affected tiles.  The adhesives applied earlier in such places shall be thoroughly removed by using proper solvents and the surface shall be cleaned to remove the traces of solvents used.  Work should be constantly checked against guidelines in order to ensure that all the four edges of adjacent tiles meet accurately. 

Any adhesive which may squeeze up between sheets or tiles should be wiped off immediately with a wet cloth before the adhesive hardens.  If, by chance, adhesive dries up and hardens on the surface of the sheet or tile, it should be removed with a suitable solvent.  A solution of one part of commercial butyl acetate and three parts of turpentine oil is a suitable solvent for the purpose.

A minimum period of 24 hours shall be given after laying the flooring for developing proper bond of the adhesive.  During this period, the flooring shall not be put to service.  It is preferable to lay the PVC flooring after the completion of plastering, painting and other decorative finish works so as to avoid any accidental damage to the flooring.

When the flooring has been securely fixed, it shall be cleaned with a wet cloth soaked in warm soap solution (two spoons of soap in 5 liters of warm water).

14.39.3. Protection edging - Where the edges of the PVC sheets or tiles are exposed, as for example, in doorways and on stair treads, it is important to provide protection against damage of the flooring material.  Metallic edge strips may be used and should be securely fastened to the sub-floor to protect edges of the flooring.

14.39.4. Maintenance - PVC flooring subject to normal usage may be kept clean by mopping with soap solution using a clean damp cloth.  Water shall not be poured on the PVC flooring for cleaning purposes as the water may tend to seep between the joints and cause the adhesive to fail.  To maintain a good wearing surface and a good appearance, the flooring may be periodically polished.  When polish is applied frequently, a thick layer builds up which collects dirt and dust and is tacky to walk on.

If the traffic is light, the floor shall be given frequent brushing; regular polishing and an application of new polish every 4 to 6 weeks.  Under moderate traffic conditions the floor shall be given an occasional wash with a wet mop but no detergents shall be used so that the polish is not removed.  Application of polish may be done every one to three weeks.  PVC flooring should not be over-waxed; when this condition develops, the coatings should be cleared off with white spirit or paraffin and a light even coat of polish applied.  When the PVC flooring has been polished, it will remain bright for a considerable period if dry mop is applied each day.  It is this daily ‘dry polish’ that maintains the glossy surface.  After exceptionally heavy traffic, PVC flooring should be swept with a hair groom, rubbed with a mop or cloth frequently rinsed in clean water, and finally rubbed dry. 

14.39.5. Determination of sub-floor dryness.

14.39.5.1. General - Three tests for determining concrete sub-floor dryness are given in the Appendix.  It is intended that the first test should be carried out as a preliminary test as it is an approximate method only, and, while adequate to separate very wet slabs from those which are dry or nearly dry, will not discriminate

Satisfactorily between the latter two conditions.  Should this preliminary test indicate that the floor is ‘dry’ confirmatory tests should be made by one of the other two procedures given in 14.39.9.3 and 14.39.9.4.

14.39.5.2. Preliminary test

14.39.5.2.1. Materials – The following materials are required:

a) A sheet of glass about 30 x 30 cm or rubber mat or a sheet of polyethylene (not less than 0.1 mm thick) or the PVC flooring material of about 60 x 60 cm; and

b) Putty, adhesive plasticize or other suitable mastic for sealing the edges of the sheet material.

14.39.5.2. 2. Procedure - A sheet of glass, rubber or plastics material shall be placed on the concrete floor slab to be tested, and sealed thoroughly around all edges, using the mastic material.

After a period of not less than 24 hours, the covered portion of the concrete slab shall be inspected for signs of dampness.  If this area is even slightly darker in colour than the remainder of the slab, the floor shall be considered too wet.  A careful inspection is required, as in conditions of good ventilation; the difference in colour may rapidly disappear after the sheet has been lifted.

The test shall be made in several places on the slab, and repeated at regular intervals until no sign of dampness appears.  The floor should then be tested at several points by either the surface hygrometer method or the electrical resistance method until satisfactory results of floor dryness are obtained before the floor should be considered sufficiently dry.

14.39.5.3. Hygrometer test

Apparatus – A hygrometer is so constructed that when sealed to the floor with mastic or by other suitable means, the relative humidity of a small quantity of air confined between the slab and the case of the instrument is measured.

Procedure – The case of the hygrometer shall be carefully sealed to the slab and left for a period not less than 16 hours.  The relative humidity reading shall then be taken.

Results – The dryness of the concrete slab shall be considered satisfactory for conditions of laying the PVC flooring, if the relative humidity reading does not exceed 70 percent.

Electrical resistance test

Apparatus – The apparatus shall comprise the following:

a) Resistance meter – One of suitable range to enable it to be calibrated in terms of the moisture content of the slab in the range of 4 to 8 percent and having sufficient sensitivity to clearly distinguish changes of 0.5 percent.

b) Electrodes – Suitable to be inserted into 25 mm deep holes drilled in the concrete slab at a fixed distance apart.

c) A suitable contact medium of conductive jelly – For placing into the electrode holes.

Procedure – After drilling holes 25 mm deep in the concrete slab at a fixed distance, set the electrodes in the holes using the conductive jelly and connect to the electrical resistance meter.  The moisture content of the floor shall then be read off to the nearest 0.5 percent from the resistance meter.  Readings shall be taken from several widely distributed locations on the concrete slab.

Results – The concrete slab shall not be considered sufficiently dry if any one of the readings taken exceeds the following:

(a)Ploughed and tongued joints ; (b) Splayed, rebated, tongued and grooved joints ;(c)Rebated, tongued and grooved joints ; (d)Tongued and grooved joints ; (e)Rebated joints ; (f)Rebated and fitted joints ; (g)Splayed joints ; and  (h) Square butt joints.

For all these joints, screws shall be driven from top of floor boards to the joists below and then concealed by putty.

The pores of timber floor shall be sealed with a floor seal.

Annexure 14-A.1

ABRASION TEST FOR CONCRETE HARDENING COMPOUNDS (Clause 14.4.1)

Preparation of sample - 25 mm cylinder shall be prepared in ratio 1:2 (1 cement:  2 graded stone) aggregate 6 mm nominal size by weight one each with and without the admixture of concrete hardening compound shall be used in the proportion by weight of cement as recommended by the firm. The cylinder shall be placed inside a damp box for 24 hours and then cured in water for 27 days.  After that, they shall be subject to abrasion test on ‘Avery Abrasion Testing Machine’, using Emery Powder No.80 as the abrasing medium under the condition given below

Conditions of test

a) Area of rubbing surface shall be same in both the cylinders.

b) Age of cylinder-28 days

c) Duration of Test - 60 minutes

d) Total distance transverse during rubbing - About 2.4 km

e) Pressure on rubbing surface.- 0.04 kg/cm2

Results of tests - The following observations shall be made in both the cases

Composition of the Test specimen

Mean thickness rubbed away

Percentage loss in weight

Remarks - Percentage loss in weight in the case of cylinders with concrete hardening compound should not be more than 40% of the percentage loss in the case of cylinder without concrete hardening compound.

Annexure 14-A.2

TEST REQUIREMENTS AND PROCEDURE FOR TESTING PRECAST CEMENT CONCRETE / TERRAZZO TILES (Clause 14.11.1 & 14.12.1)

Sampling - The tiles required for carrying out test described below shall be taken by ‘random sampling’.  Each tile sample shall be marked to identify the consignment from which it was selected.

Minimum quantity of tiles for carrying out the test and frequency of test shall be as specified in the list of Mandatory Test.  The number of tiles selected for each mandatory test shall be as follows;

a) For conformity to requirements on shape and dimensions, wearing layer, and general quality. - 12 tiles

b) For wet transverse strength test - 6 tiles

c) For resistance to wear test - 6 tiles

d) For water absorption test - 6 tiles

Note:1) The tests on the tiles shall not be carried out earlier than 28 days from the date of manufacture.

(2) The tiles selected for (a) may as well after verification of requirements, be used for (b).

Wet transverse strength test - Six full size tiles shall be tested for the determination of wet transverse strength.  When tested according to the procedure laid down in Appendix ‘E’ of IS: 1237, the average wet transverse strength shall not be less than 3 N/mm2 (30 kgf/cm2).

Resistance to wear test - Not less than twelve specimens shall be prepared as described.  From the tiles selected in accordance with B.1.  When tested in the manner as specified their average wear shall not exceed 3.5 mm and the wear on any individual specimen shall not exceed 4 mm.

Preparation of test specimens - The test specimens shall be square in shape and of size 7.06 cm x 7.06 cm (i.e., 50 sq. cm in area).  They shall be sawn off one only from each tile, preferably from the central part of the tile.  The deviation in the length of the specimen shall be within ± 2 per cent. The surface to be tested shall be ground smooth and filling removed.

Apparatus and accessories

Abrasion testing machine - The abrasion test of specimens shall be carried out in a machine conforming essentially to the requirements described in IS: 1237-1980 (Appendix “F”).  The abrasive powder used for the test shall conform to the specification given below. The abrasive shall have an aluminium oxide content of not less than 95 per cent by weight. The grains shall be of rounded shape and shall generally pass through IS Test Sieve 25 and be retained on IS test Sieve 20. The combined content of larger grains retained on IS Tests Sieve 25 and of smaller grains who’s finest is not limited, shall not exceed 10 per cent.  The specific gravity of the grains shall be between 3.9 and 4.1.  The grains shall generally have a hardness of 9 in Mohr’s scale.

Measuring instruments - A suitable instrument capable of measurement to accuracy of 0.01 mm shall be used for determining the change in the thickness of the specimen after abrasion.

Procedure of test - The specimen shall be dried at 110 degree C for 24 hours and then weighted to the nearest 0.1 gm. The specimen after initial drying and weighing shall be placed in the thickness measuring apparatus with its wearing surface upper most of the reading of the measuring instrument taken.

The grinding path of the disc of the abrasion testing machine shall be evenly strewn with 20 gm of the abrasive powder. The specimen shall then be fixed in the holding device with the surface to be ground facing the disc and loaded at the centre with 30 kg. The grinding disc shall then be put in motion at a speed of 30 rpm. After every 22 revolutions, the disc shall be stopped, the abraded powder shall be removed from the disc and fresh abrasive powder in quantities of 20 gm applied each time.  After 110 revolutions, the specimen shall be turned about the vertical axis through an angle of 90 degree and then the test continued under the same conditions until 220 revolutions have been completed altogether. The disc, the abrasive powder and the specimen shall be kept dry throughout the duration of the test.  After the abrasion is over, the specimen shall be re-weighed to the nearest 0.1 gm.  It shall then be placed in the thickness measuring apparatus once again in the identical manner and the reading taken with the same position and setting of the dial gauge as for the measurement before abrasion.

Determination of wear - The wear shall be determined from the difference in readings obtained by the measuring instrument before and after the abrasion of the specimen.  The value shall be checked up with the average loss in thickness of the specimen obtained by the following formula.

                  (W1 – W2) V1

t = 10 x ---------------------------------

                    W1 X A

Where

t = Average loss in thickness, in mm;

W1 = Initial weight, in gm of the specimen;

W2 = Final weight, in gm of the abraded specimen

V1 = Initial volume, in C. C., of the specimen, and

A = Surface area, in sq. cm of the specimen.

Water absorption - At the time of delivery to the site of the work, not less than six full tile specimens, selected in accordance with B1, shall be prepared and then tested as described below, their average percentage of water absorption shall not exceed ten.

Preparation of specimen - Full size tiles shall be used for this test.  They shall be immersed in water for 24 hours, then taken out, wiped dry and tested for water absorption.

Procedure of test - Each tile shall be weighed immediately after saturation and wiping.  The tile shall be oven dried at a temperature of 65 ± 1 degree C for a period of 24 hours, cooled to room temperature and re-weighed.

Determination of water absorption - The water absorption per cent by weight for each tile shall be determined as follows

On oven dry basis water per cent by weight

=   (W1 – W2) x 100

   -----------------------

           W2

Where

W1 = Weight in gm of the saturated specimens, and

W2 = Weight in gm of the oven dried specimen

The average value for percentage water absorption shall be calculated for the whole number of tiles tested.

Annexure 14–A.3

SPECIES OF TIMBER RECOMMENDED FOR SLATS, FLOOR BOARDS AND PARQUET FLOORS (Clause 14.37.10)

Name

Hardness

Name

Hardness

1

Gurjan

135

14

Kindal

95

2

Rohini

130

15

Pali

90

3

Padauk

130

16

Kokko

90

4

Satinwood

130

17

Rosewood

90

5

Maniawga

125

18

Kassi

85

6

Axlewood

120

19

Sissoo

85

7

Kala Siris

120

20

Piney

85

8

Bijasal

100

21

Jarul

80

9

Laurel

100

22

Hollock

75

10

White chuglam

100

23

Anjan

70

11

Teak

100

24

Fir

65

12

Lendi

95

25

Cypress

60

13

White Cedar

95

26

Machillus

55

Annexure 14-A.4

SPECIFICATIONS FOR DETERMINATION OF SUB-FLOOR DRYNESS (Clause 14.25.3.)

General - These tests for determining concrete sub-floor dryness are given in this appendix. It is intended that the first test should be carried out as preliminary test as it is an approximate method only, and is adequate to separate very wet slabs from those which are dry or neatly dry, but will not discriminate satisfactorily between the latter two conditions. Should this preliminary test indicate that the floor is ‘dry’ confirmatory test should be made by one of the other two procedures as given.

Preliminary test - The following materials are required

a) A sheet of glass about 30 x 30 cm or rubber mat or a sheet of polyethylene (not less than 0.1 mm thick) or the PVC flooring material of about 60 x 60 cm and

b) Putty adhesive plasticine or other suitable mastic for scaling the edges of the sheet material.

Procedure - A sheet of glass, rubber or plastic materials shall be placed on the concrete slab shall be placed on the concrete floor slab to be tested, and sealed thoroughly around all edges, using the mastic material.

After a period of not less than 24 hours, the covered portion of the concrete slab shall be inspected for signs of dampness. If this area is even slightly darker in colour than the remainder of the slab, the floor shall be considered too wet. A careful inspection is required, as in conditions of good ventilation; the difference in colour may rapidly disappear after the sheet has been lifted.

The test shall be made in several places on the slab, and repeated at regular intervals until no sign of dampness appears. The floor should then be tested at several points by either surface hygrometer method or the electrical resistance method until satisfactory results of floor dryness are obtained before the floor should be considered sufficiently dry.

Hygrometer test

Apparatus - A hygrometer is so constructed that when sealed to the floor with mastic or by other suitable means, the relative humidity of a small quantity of air confines between the slab and the case of the instrument is measured.

Procedure - The case of the hygrometer shall be carefully sealed to the slab and left for a period not less than two hours. The relative humidity reading shall then be taken.

Results - The dryness of the concrete slab shall be considered satisfactory for conditions of laying the PVC flooring, if the relative humidity reading does not exceed 70 per cent.

Note: The instrument shall be so placed that sunlight does not fall on it, as this may produce a false low reading.

Electrical resistance test

Apparatus - The apparatus shall comprise the following

Resistance Meter -  One of suitable range to be calibrated in terms of the moisture content of the slab in the range of 4 to 8 per cent and having sufficient sensitivity to clearly distinguish changes of 0.5 per cent.

Annexure 14-A.5

SPECIFICATIONS FOR BITUMEN MASTIC FOR FLOORING FOR INDUSTRIES HANDLING LPG AND OTHER LIGHT HYDROCARBON PRODUCTS (Extract of IS: 13026-1991)

1.  Scope

1.1. This Annexure specifies requirements of bitumen mastic flooring for industries handling LPG and other light hydrocarbon products.

1.2. This Annexure is also applicable for explosive and crackers manufacturing factories, ordinance factories, ammonia depots, etc.

1.3. This Annexure is not applicable for less volatile materials such as kerosene, diesel and lubricating oil.

2.  References - The Indian standards listed in 8 are necessary adjuncts to this standard.

3. Terminology - For the purpose of this standard terminologies given in IS: 334-1982 shall apply.

4.  Materials

4.1. Bitumen- Properties of bitumen conforming to IS: 702 -1988 shall be as specified below

Physical properties of bitumen (Clause 4.1)

Sl. No.

Characteristic

Requirement

Method of test

i

Softening point ( ring 65 to 1000 c and ball method )

65 to 1000 C

IS: 1205-1978

ii

Penetration at 270 C in 100 cm

10 to 40

IS: 1203-1978

iii

Loss on heating, % Max

0.3

IS: 1212-1978

iv

Solubility in CS2, % Min

99

IS: 1216-1978

v

Dctility at 270C, Min

2

IS: 1208-1978

4.2. Aggregates and fillers - Aggregates and fillers used in preparing bitumen mastic should be lime stone and other carbon black / graphite materials.   The lime stone should have calcium carbonate content of maximum 75 percent.  The combined grading of aggregates shall be as specified below

Grading of Aggregates and Fillers

Sieve Designation

Percentage by Mass

Passing IS Sieve

Retained on IS Sieve

90 microns

-

45 to 55

212 microns

90 microns

10 to 30

600 microns

212 microns

10 to 30

2:36 mm

600 microns

6 to 20

-

2:36

Nil

5.  Composition - Bitumen mastic composition is made by adding suitable materials like carbon black / graphite of conducting type. The bitumen content shall be between 13 and 18 percent by mass of the total mastics. Carbon black / graphite content shall be finer than 90 micron IS sieve with certain content more than 60 percent by mass.

5.2.   Preparation of bitumen mastic - The aggregates and fillers shall be heated in a mastic cooker to a temperature of 120 to 1500C and then the required quantity of bitumen heated to 170 to 1800C added to it.  These shall be mixed and cooked for about 3 hours until the homogeneous mass is obtained taking care t hat the temperature does not exceed 2050C at any time.

6.  Properties - The hardness number of bitumen mastic as laid and tested as per method described in 9 shall be 4 to 12 at 350C. The resistance to products after being manufactured according to 5.2 and when tested in accordance with 7 shall have electrical resistance between 5 x 144 ohms and 2x106 ohms.

7.  Test procedure for measuring electrical resistance

7.1. Preparation of sample - In preparing sample for test, mastic as laid shall be filled directly from the mixer at the time of laying, into moulds which re not less than 100mm in diameter or 100mm square and float finished. The sample, which shall be taken in duplicate, shall be molded to a thickness of 25 mm.  Where it is necessary to perform test on samples taken out from the floor, special precautions should be taken to ensure that the base is level and the sample is of uniform thickness.  The sample should not be re-melted.

7.2. Preparation of the Surface - The surface to be used in test shall be cleaned by rubbing with dry Fuller's earth using a clear pad of cotton wool, care being taken to avoid straining the material.

7.2.1. After all traces of the powder have been cleaned away, the surfaces shall be wiped over with a pad moistened with distilled water and rubbed dry with a clean cloth.

7.3. Test procedure - Immediately after the preparation of the surface, liquid electrodes and metal contacts as described in 10 shall be applied as given in 11.  It shall then be kept at a temperature of 27 ± 20C at a relative humidity of less than 70 percent, and the resistance test as specified shall be carried out after a period of not less than 15 minutes or more than two hours.  As some materials are sensitive to moisture, great care shall be taken to avoid breathing on the samples prior to and during the resistance test.

8. List of referred Indian standards  (Clause 2.1) 

IS No.

Title

IS No.

Title

334-2002

Glossary of terms relating to bitumen and tar

( second revision )

1208-1978

Methods of testing tar and bituminous materials : Determination of ductility

( first revision )

702-1988

Industrial bitumen

( second revision )

1212-1978

Methods of testing tar and bituminous materials : Determination of loss on heating  ( first revision )

1203-1978

Methods of testing tar and bituminous materials: Determination of penetration

( first revision )

1216-1978

Methods of testing tar and bituminous materials: Determination of solubility in carbon disulphide or trichloro-ethylene ( first revision )

1205-1978

Methods of testing tar and bituminous materials: Determination of softening point ( first revision )

 

 

9. Method for determining hardness number (Clause 6.1)

9.1. Definition of Hardness Number - The hardness number is the figure denoting the depth, in hundredths of a centimeter, to which a flat-ended indentation pin in the form of a steel rod 6.35 mm in diameter will penetrate the mastic under a load of 317 N, applied for 1 minute, the temperature being maintained at 350 ± 0.50C.  This load is equivalent to 10 N/mm2 and is conveniently applied by means of a lever giving a suitable mechanical advantage.

9.2. Apparatus

The apparatus employed should be capable of fulfilling the above requirements accurately.  One convenient form of apparatus is shown in Fig.1

A – Yoke, stalk and tray

J – Indicating needle

B – Weight (central hole)

K – Beam support yoke

C – Weight (slotted)

L – Support bracket

D – Indentor pin spindle

M – Calibrated dial

E – Lock lever

N – Water bath

F – Spindle head

P – Control for water stirrer

G – Adjusting nut

R – Control for heater blade and thermostat

H – Beam

S – Bath illuminator

Fig 1 A type of apparatus for hardness testing

9.3. Method

9.3.1. In order to ensure that the test results are reproducible, particular attention is called to the points given in 9.3.2 to 9.3.5

9.3.2. Samples - In preparing samples for test, the mastic as laid shall be filled directly from the mixer at the time of laying, into moulds which are not less than 100mm in diameter or 100mm square and float finished.  The samples, which shall be taken in duplicate, shall be moulded to a thickness of 25 mm.  Where it is necessary to make a test on samples cut from the floor, special precautions should be taken to ensure that the sample is of uniform thickness and that the base is level.  The samples should not be remitted.

9.3.3. Test temperature - For the purpose of this standard, the sample shall be cooled for not less than three hours in air or not less than one hour in cold running water.  It shall then be immersed in water at a temperature of 35 ±  0.50 C for at least one hour immediately prior to testing and shall be maintained at that temperature during the test.

9.3.4. Adjustment of pin - Before the load is applied, the indentation pin shall be adjusted lightly but firmly in contact with the surface.  The pressure should not be greater than necessary to prevent lateral movement of the specimen.

9.3.5. Testing - The requisite load shall then be applied for exactly 1 minute and the depth of indentation recorded in hundredths of a centimeter.

9.3.6. Test results - Test points shall be not less than 25mm apart and not less than 25mm from the edge.  At least five readings shall be taken and the results averaged.  If any result differs from the mean by more than two hardness’s determined, except that if there are fewer than four results to be averaged the sample shall be discarded and the test shall be made on another samples.

10. Liquid electrodes and contacts and testing instruments (Clause 7.3)

10.1. Liquid electrodes - Liquid electrodes shall be formed on the surface by means of a conducting liquid. This shall consist of:

Anhydrous polyethylene glycol of mol wt 600 - 800 parts

Water - 200 parts

Soft soap - 1 part

Potassium chloride - 10 parts

The electrode area shall be completely wetted and remain so until the end of the test.

Clean metal contacts shall be applied to the wetted areas so that the contact area is approximately of the same size as but not greater than the wetted area.  The surface of the product shall not be deformed either during the application of the contacts or during the test.

10.2. Testing instruments - The test shall be carried out with an insulation tester having a nominal open circuit voltage of 500 V d.c. or, with any suitable instrument known to give comparable results.  For values of resistance above 106 ohms, an instrument with nominal open circuit voltage of 1000 V d.c may be used. The instrument shall be sufficiently accurate to determine the resistance within 5 percent and shall not dissipate more than 3 W in the specimen.  The voltage shall be applied for no longer than is necessary to carry out the test in order to reduce the risk of overheating the test piece.

11. Tests for electrical resistance for bitumen mastic floor (Clause 7.3)

Procedure - The test is performed on one surface.  Apply liquid electrodes to two areas, each approximately 25 mm2, located on the same surface to be tested and situated so that the dry distance between the facing edges is 50 ± 6 mm.  Apply the metal contacts to the wetted areas and measure the resistance. This test shall also be performed on the sample to measure the electrical resistance across the surface. 

Annexure 14-A.6

SPECIFICATIONS FOR LAYING OF BITUMEN MASTIC FLOORING FOR INDUSTRIES HANDLING LPG AND OTHER LIGHT HYDROCARBON PRODUCTS (Extract of IS: 13074-1991)

1.  Scope

1.1. This Annexure lays down the procedure for laying bitumen mastic flooring for industries handling LPG and other light hydrocarbon products.

2.  Reference - The Indian standard IS: 13026-1990 ' Specification for bitumen mastic flooring for industries handling LPG and other light hydrocarbon products ‘is a necessary adjunct to this standard.

3. Design consideration - Bitumen mastic is jointless and impervious to the transmission of moisture.  In designing the bitumen mastic flooring for hydrocarbon services, consideration shall be given to the anticipated service conditions as specified in IS: 13026-1990

4.  Thickness - The total thickness to which bitumen mastic should be laid shall be 20 mm to 25mm or as mutually agreed upon by both parties depending on actual conditions.

5.  Material - Bitumen mastic shall conform to the requirements given in IS: 13026-1990

5.2. The bitumen mastic may be delivered to the site in the molten state and immediately laid.

6.  Equipment - The equipment shall consist to bitumen boiler, a mechanically agitated mastic cooker and other accessories.  The equipment shall be used near the site, so as to prevent cooling of the molten material.

7. Construction - The base on which the bitumen mastic is to be laid shall be stable to receive the mastic and to sustain the anticipated load on it.

7.2. Preparation of the Base - The base shall have an even and dry surface which has been roughened with stiff broom or wire or coir brush and should be free from ridges and hollows.  The base may be provided with suitable slope if needed for drainage of rain water etc.,

7.3. Laying

7.3.1. Transport of Molten Material - The molten mastic shall be carried in flat mortar pans.  The pans are sprinkled with lime stone dust, to prevent sticking of mastic.  Grease or oil shall not be used.

7.3.2. Spreading - Bitumen mastic should be laid in bays in one or more layer.  The specified thickness is maintained by suitable hand tools, gauges, straight edges, band levels, etc. The bubbles formed during laying should be punctured and the area rectified while mastic is hot. Multi-layer work should be treated in same manner as that of single-layer, care being taken to arrange that the joints in successive layers are staggered.

7.3.3. Protection of the surface - The laid surface shall be protected from damage due to movement of heavy load, spillage of oils, etc.  Bitumen mastic surface should not be used for preparation of cement concrete mixes or mortars.

7.3.4. Opening to traffic - The mastic flooring should not be opened to traffic until the material has cooled down to ambient temperature of the surrounding atmosphere.

8.  Repairs - Damaged area shall be cut rectangular and replaced with new mastic.  Blow lamp techniques to remove damaged layer are preferred.

9.  Maintenance - The bitumen mastic flooring requires little maintenance.  Dirt and dust should be periodically removed with lukewarm water and detergent.  Oils, fats and grease spilled, should be removed immediately.

Annexure 14-A.7

SPECIFICATIONS FOR LINOLEUM SHEETS (Clause 14.37.4)

Materials - Linoleum shall consist of a composition pressed on Hessian backing. There shall be adequate Hessian between the composition and the Hessian backing. The composition shall contain oxidized or polymerized, linseed oil conforming to IS: 75 specification for linseed oil or other suitable drying oiler with necessary driers, fossil and /or resin intimately mixed with ground cork or wood flour or both and pigments. The Hessian used for the backing shall have not less than 43 ends and 33 shots per decimeter. A piece 90 x 100 cm will weigh not less than 220 gram. Unless specified otherwise, the paint when used for painting the Hessian backing shall conform to IS:  640.

Dimensions - The linoleum shall be manufactured to the following thickness

Thickness (mm)   Type

6.7                           All

6.0                      Plain and Marble

4.5                           All

3.2                           All

2.0                           All

1.6                   Moire and Jaspe

Measurement and thickness - The thickness of linoleum shall be measured with a micrometer gauge or a dial micrometer gauge having a flat foot and capable of reading up to 0.01 mm. The foot of the micrometer gauge shall exert a pressure of 1.5 kg/cm2 on the linoleum surface.  The measurement shall be made at least at 16 points and the mean value shall not vary by more than 0.1 mm from the specified thickness.

Width - Unless otherwise, the width of the linoleum shall be 2 m with a tolerance of ± 1.5 mm.

Length - Unless specified otherwise, all types of linoleum of all thicknesses other than 6.0 and 6.7 mm thicknesses shall be supplied in rolls of length of not less than 5.5 m.  In case of 6.0 and 6.7 mm thicknesses linoleum, the length shall be not less than 3 m.  The length shall be measured to the nearest centimeter.

Colour - The composition of plain linoleum shall be of uniform colour extending evenly throughout the thickness from the surface to the Hessian backing to form a sheet of approved colour.

In moire, jaspe and marble sheet linoleum portion of the mix shall be of different colours and shall be compressed into a single sheet.  The several colours shall extend from the surface to the base in random relation to form a variegated surface showing an approved pattern.

Finish - The surface of the linoleum shall be smooth, uniform and free from indentations and protrusions. The Hessian backing shall be unpainted unless otherwise specified.

Annexure14-A.8

SPECIFICATIONS FOR LAYING, FIXING AND MAINTENANCE OF LINOLEUM FLOORS

(Extract of IS: 1198-1982) (Clause 14.37.4.4)

0.1. Linoleum provides a satisfactory floor for residential and public buildings, railway coaches, ships, etc. It is also suitable for most types of non-industrial floors. In light industry such as in electronic industry, linoleum flooring may be used, as the risk of damage by cutting, to which linoleum is vulnerable, is small. However, if linoleum gets wet, it expands and eventually rots. This standard has been prepared with a view to guiding the users in regard to laying, fixing and maintenance of linoleum floors.

0.2. This IS standard has incorporated improvements found necessary in the light of usage of the standards and the suggestions made by various bodies implementing it. In this separate clause on suitability of linoleum for various conditions of use has been added and the materials used as underlay for aspects like preparation of sub floors, fixing of under lays, laying of linoleum has been dealt with, in detail. This also suggests the laying and fixing method of linoleum in tile form.

1. Scope

1.1. This Annexure recommends details of work necessary for laying, fixing initial treatment, and subsequent maintenance of linoleum flooring in sheet and tile form.

2. Terminology

2.1. Sub-floor - The surface on which flooring is to be laid.

2.2. Underlay - A layer of prefabricated material or in-situ filling on the sub-floor to provide a smooth level surface to receive the flooring.

3. Necessary information

3.1. For the efficient planning and execution of the work, detailed information with regard to the following is necessary:

(a) Purpose for which the floor is to be used; (b) Floor area to be covered; (c) Location and size of

openings and ducts, drainage outlets, if any, to be left out; (d) Details of the sub-floor, (e) Type of soil in the sub-base and any seepage problem.

3.2. All the information stated in 3.1 shall be made available by the appropriate authority responsible for the construction of the whole building to those who are entrusted with the work of laying linoleum

floor finish before the work is started. Necessary drawings and instructions for preparatory work shall also be given where required.

3.3. Arrangements shall also be made for the proper exchange of information between those engaged in laying the floor and all others whose work will affect or will be affected.

4. Suitability

4.1. Linoleum is suitable for use in domestic buildings, and those of non-industrial character where the traffic is expected to be essentially pedestrian. However, the following factors must be considered before it is being laid. The thicknesses recommended are 4.5 and 3·2 mm for commercial and institutional buildings respectively and 1.6 mm for domestic or where traffic is low.                                   

4.1.1. Resistance to rising damp - Linoleum requires an adequately dry sub-floor. If inconveniences of damp proofing are not acceptable, linoleum should not be used.

4.1.2. Exposure to weather - Linoleum is not suitable for installation except where it is wholly inside a building.

4.1.3. Resistance to chemicals - Linoleum is resistant to oils, fats and greases. Thicker gauges shall be used where heavy traffic is expected.

4.1.4. Indentation resistance - Linoleum is not resistant to indentations particularly from heels or static load. Cork tile will withstand heavy foot traffic but indents if heavy objects are left in one position for some time or pushed.

4.1.5. Slip resistance - Linoleum when highly polished or wet can become dangerously slippery. The polish with a reduced tendency to slipperiness may be used. The cork tile flooring provides a slip resistant surface except when liquid wax polish is applied over a seal.

5. Material

5.1. Flooring - The flooring shall comply with the requirement specified in IS: 653-1981.

5.2. Underlay - The underlay may be as given below:

a) For Timber Sub floors:

i)  Plywood at least 4 mm thick (see IS: 303-19751)

ii) Hardboard at least 3 mm thick see IS: 1658-19771)   and

iii)  Fibre based bitumen felt I mm thick (see IS: 1322-1970)

b) For Concrete Sub floors:

i)  Bitumen mastic (see IS: 1195-1978) and

ii)  Bitumen (see IS: 1580-1969).

5.3. Adhesives - The type of adhesive to be used and the manner of use shall be those recommended by the floor covering manufacturer and the adhesive shall be compatible with the floor covering and suitable for bonding the floor covering to the underlay or sub-floor. Adhesives shall not

be considered effective as damp-proof membrane. Information on types of adhesives is given below.

5.3.1. Vegetable and casein glues - Vegetable  (starch) glue is usually in the form of a paste, and casein glue usually in the form of a powder which is mixed with water before use Both the types are spread on the base and the linoleum is pressed on to it Vegetable adhesives are effective but take some time to harden. They are unsuitable for situations where a lot of water is likely to be spilt on the linoleum. These glues are liable to attack by fungi.

5.3.2. Lignin pastes

5.3.2.1. Lignin, a by-product of paper manufacture is mixed with clay to form an adhesive which is applied thinly to the base and the linoleum pressed on to it. It resembles starch and casein glues but it is more resistant to water.

5.3.3. Gum-spirit adhesives - Adhesives made from gum or resin, filler and methylated spirit are characterized by their strong smell. The adhesive is spread on the base previously rendered dry. As the spirit evaporates, a skin forms on the surface; the linoleum is pressed into the adhesive before the skin becomes too thick. The linoleum can, therefore, be spread only a few square metres at a time.

Any excess of spirit evaporates slowly through the linoleum or is absorbed by the sub-floor. Gum-spirit adhesives are resistant to damp but are likely to be attacked by dilute alkaline solutions such as those that rise through wet concrete.

5.3.4. Bitumen-rubber emulsions - This type of adhesive is a dark coloured emulsion of rubber and bitumen or coal-tar pitch in water. There is no smell of solvent in this case. The water in the adhesive must evaporate before the linoleum is laid, as there is a risk of blistering if the linoleum absorbs the water. The evaporation is noted by the colour of the adhesive, which changes from chocolate to black. When the colour is black, it is safe to lay the linoleum. This type of adhesive and the solution type described under A-5 are what may be called 'one-chance' adhesives; when the linoleum is placed on them it is fixed and cannot be slid into position. The bitumen-rubber emulsions are resistant to water and, when set, are water-repellent. When used as adhesives they should not, however, be taken to serve as damp-proof courses.

5.3.5. Bitumen-rubber solution - Bitumen-rubber solution adhesive is dark coloured, of thick consistency and is recognizable by the strong smell of petroleum solvent.  The solution is applied both to the back of the linoleum and to the floor and the solvent allowed to evaporate before the linoleum is laid. During this period, as a precaution against fire, the room shall be well-ventilated and no smoking or naked flame shall be allowed. As adhesives, they are resistant to water and are water-repellent but do not serve as damp-proof courses.

6. Preparation of sub floors

6.1. The linoleum flooring gives maximum, service if laid on a firm base. Evaporation of the moisture from the sub floor cannot take place once linoleum is laid. Therefore, it is important that sub floors should be thoroughly dry before laying of the linoleum. An irregular, sub floor surface creates poor adhesion between the sub floor and the linoleum. Therefore, the sub floor should always be smooth and level. Recommended treatments for different sub floors are given under 6.2 to 6.4.

6.2. Timber - All timber sub floors shall be sound, rigid, level and dry. The timber should be at equilibrium moisture content at the time it is covered with the underlay or the floor covering. A timber floor should always be well ventilated, to discourage fungal attack.

6.2.1. New timber floors - In the case of new construction, seasoned and treated timber shall be used and shall be of tongued and grooved boarding. Boards shall be narrow and of equal width (say 100mm). Boards of unequal width have various degree of shrinkage. Before fixing the linoleum, all nail heads on the timber sub floor shall be punched down, regulations planned off and the holes filled with plaster, plastic wood or similar fillers. After the boards have been nailed to the joists, the floor is usually firm enough for direct laying of the linoleum, but however, under lays such as plywood or hardboard or fibre based bitumen felt may be used prior to fixing of the linoleum to prevent any movement in the boards. Suspended timber floor shall be adequately ventilated with a minimum air gap below the underside of the joist to stop the growth of rot. Wood blocks and boarded floor on concrete on the ground shall not be covered with linoleum unless an efficient damp-proof membrane in the concrete below the blocks or boards has been provided.

6.2.2. Existing timber floor - In the case of an existing timber floor, covered with boarding when it is not possible to obtain an even surface or in cases of dry rot, the use of diagonal boarding is recommended, after removing and replacing some of the badly affected boarding and filling in the cracks with plastic wood or similar filler and after disinfecting the floor. Alternatively, plywood topping on the existing boarding also gives an even surface. It is important, however, to see that the floor is well ventilated, and if it is a ground floor, by means of air-ducts in the outer walls and sleeper walls with honeycombed pattern for free circulation of air.

6.3. Concrete - All concrete sub floors may be finished with cement and sand or fine concrete screed laid according to the recommendations of IS: 2571-1970. The sub floor surface shall be smooth and flat. Concrete is not completely impervious. As moisture either in liquid or in vapour form and rising damp may cause damage to linoleum, concrete sub floor intended as a base for linoleum shall contain an effective damp-proof course. The damp-proof course shall be laid in any one of the ways given below.

6.3.1. The most effective treatments for existing floors to protect it against rising damp is a layer of bitumen mastic not less than 15 mm thick laid over the sub floor according to the recommendations given in 1S:1196-1978.

6.3.2. For new work the sub floor shall be laid as per the recommendation given in IS: 2571-1970. Information on the limitations of damp-proof materials is given below.

A

Water proofing materials

Properties / limitations

1.

Bitumen mastic laid according to IS: 1196-1978

Impervious to the transmission of moisture.  May be used as floor finish or as an underlay; where concrete is laid direct to earth, an isolating membrane should be used.

B

Sandwich Membranes

 

1

Bitumen mastic

Impervious to moisture

2

Bitumen felts

When joints are properly sealed, it is impervious

3

Hot applied bitumen

When laid on a primed surface with suitable thickness it may be regarded as impervious; care shall be taken to avoid pin holes

4

Cold applied bitumen, bitumen rubber emulsion

Repeated application can form an impervious layer; care in workmanship and maintenance is needed.

6.3.3. Waterproofing materials mixed with concrete do not produce an effective barrier against rising damp.

6.3.4. Before linoleum is laid, ample time shall be allowed for the water to dry from both suspended and ground concrete floors. It is difficult to specify the period required as this depends on weather and

on the quality and thickness of the concrete, but a period of 4 to 8 weeks at least shall be allowed for drying under normal conditions. This time may be reduced if the building is heated and if the ventilation is good.

6.3.5. In new work, the finish required for laying linoleum should be usually produced with a steel

trowel on a screed applied to the base concrete. The finish may, however, be produced on the base concrete itself if a power-float is used. With old concrete, if the surface is only slightly uneven, the holes shall be filled with a skim layer of proprietary bitumen-cement or latex-cement leveling coat. For rougher surfaces, an underlay of asphalt, bitumen-cement or latex-cement is necessary. Of these, latex-cement can be used in the least thickness. If sub-floors are dusty, it is a-safe practice to use a primer such as bitumen emulsion before using an adhesive. Concrete hardeners or densities may also be used with advantage to bind the surface of the screed.

6.4. Other sub floors - Some bases such as clay tiles, concrete tiles or terrazzo are unaffected by dampness, but may be sufficiently porous to allow moisture to pass through to the back of the floor finish. These bases shall be damp-proofed when necessary by using under felt. Bases such as magnesium oxy chloride in good conditions are suitable for receiving linoleum but are adversely affected by dampness rising through concrete from the ground and shall not be covered with a damp-proof layer. Unless it can be established that there is an effective damp course below these materials, they shall be removed before laying the Linoleum. Bitumen mastics are excellent bases to receive linoleum but solvent type adhesives may soften the mastic and mastics, which are soft and are likely to be dented, are not suitable for linoleum.

7. Laying

7.1. General - Linoleum should be stored in room temperature of not less than 200C for at least 48 hours before it is unrolled. It shall be laid out flat for several days before it is cut to size because, after

being unrolled, it shrinks in length and expands in width. As the humidity in the room is usually greater than that at which the linoleum was rolled, it absorbs moisture and being unrestrained, expands. If the linoleum is cut to fit closely round the skirting, it will often be found necessary after a time to retrim the material. When two widths of linoleum meet, they shall be left with one overlapping the other until expansion has stopped and then cut to fit. Cork tile should be dimensionally stable in the condition of use. In order to achieve this, tiles should be removed from the cartons at least 48 hours before lying is to commence and be distributed in the room in humidity and temperature conditions similar to those likely to prevail in occupation.

7.1.1. Before starting to lay the linoleum, the position and depth of cables, water pipes in the floor screed, etc, should be ascertained and all preliminary work should be completed. The sub floor should be firm and dry and tested for dampness as given in 7.1.1.1 to 7.1.1.4.  Dusty sub floor should be swept and porous sub floors should be primed as recommended by the adhesive manufacturer.

7.1.1.1. The tests as prescribed shall be conducted to determine the dampness of floor while laying linoleum.

7.1.1.2. Rubber test - Place one square meter of rubber matting and place it loosely, with the smooth side down, on the floor to be tested. The matting shall be left for twenty-four hours for ordinary floors and forty-eight hours for unusually smooth floors. If, after this period, on removing the matting the concrete shows a dark patch, it is an indication that the floor is not sufficiently dry to receive linoleum.

7.1.1.3. Anhydrous copper sulphate test - This test is much more rigorous than the rubber test and is thus more certain. Take an ordinary piece of window glass about 40 cm square, lay the glass on the area of the floor to be tested and mark the floor round the glass with pencil. Remove the glass and lay an even heading 12 mm thick, of well-worked putty inside the pencil line. Spread evenly one tea spoonful of anhydrous copper sulphate powder inside the putty and cover immediately with the glass, pressing the glass firmly into the putty, so that the copper sulphate is kept air-tight. The copper sulphate should be white when it is put in position; if after six hours it has turned green or blue it is clear indication that the concrete is still too damp to receive linoleum.

7.1.1.4. Moisture meter test - Floors may be tested for dampness by means of a pocket hygrometer placed in contact with the floor. The edges shall be sealed with putty if the floor is rough. The humidity of the enclosed air is read directly on the scale of the hygrometer. The air usually takes not less than the instrument in position overnight and takes the reading in the morning. As a general rule, a value of 70 to 75 shall be below 80 before it can be assumed that the concrete above the damp course has dried sufficiently for it to be suitable for the fixing of linoleum.

7.2. Adhesives - The linoleum shall be laid either loose or fixed to the sub floor by means of suitable adhesives. Any priming coat should be allowed to dry before the adhesive is spread. Adhesives are spread with a closely notched trowel as recommended by the manufacturer to ensure even the coverage of the sub floor to the correct thickness. It is essential that where low flash solvent adhesive (containing petroleum or naphtha) are used, the use of naked lights should be prohibited in the vicinity of the laying operations. The area shall be well ventilated even when non-flammable solvents are used in the adhesives. Smoking shall be prohibited.

7.3. Fixing of under lays - Plywood, hardboard shall be securely fixed to the sub floor in the form of sheets using staple, and nails. Fixing shall start at the centre of the sheet and secured at 100mm intervals around the side. All nail heads shall be finished flush with the surface. Joint lines shall be staggered and every effort shall be made to prevent coincidence in joints in the sheet and timber base. A suitable gap shall be left between the sheets for possible expansion due to atmospheric changes. Except where recommended, hardboard may be laid with the smooth face uppermost. When a felt underlay is used all surfaces to be covered shall be thoroughly cleaned free from dust and dirt. No surface shall be cleaned with water as dryness is essential.

Bitumen felts shall be cut to size and fixed with the adhesives as recommended by the manufacturer. It shall be butt jointed and laid across the boards so that the joints run in a direction at right angle to the joints in linoleum. The joints shall not coincide with those in linoleum sheets. After fixing, the felt shall be smoothed down and well rolled. Bitumen mastic shall be laid in accordance with the recommendations as given in IS: 1196-1978, where the mastic is used as underlay and damp-proof coarse, care shall be taken to connect it with the damp proof course in the walls. Other underlay as given in 5.2 should be laid as per the recommendations of the manufacturer.

7.4. Fixing - The base over which the linoleum is to be fixed shall be thoroughly cleaned free from dirt and dust, chemicals, oils, paints, etc. The adhesive shall be spread evenly with a trowel as recommended by the manufacturer. The linoleum shall be firmly pressed into the adhesive within the recommended setting time of adhesive. To give maximum adhesive contact and to secure a bond, the material shall be well rolled with a floor roller weighing approximately 70 kg working from centre to the walls. If necessary the linoleum may be loaded with sand bags at various points until the adhesive has gripped. When laid directly on concrete, it is desirable to prime the back of the linoleum with the adhesive. Cork tiles shall be fixed with the adhesive, which should be spread evenly with the trowel in sufficient quantity for laying only a few square meters at a time. Each tile shall be carefully placed in position to exclude air beneath the tile and also to attain proper joints between the tiles. It is advisable to use headless steel pins in conjunction with the adhesive in order to maintain contact between sub floor or screed and tile. The pins shall be driven below the surface of the tile with a hammer. If the sub floor or screed is too hard for pins, it may be necessary to weight down any lipping tiles.

7.4.1. Coving and skirting - Linoleum coving and skirting shall be formed from sheet material on the job in grades up to 3.2 mm thick. First, cove stick shall be fixed in the angle between floor and wall to give the correct contour to the cove. The linoleum, in the lengths up to 2.5 m is turned 15 cm up the wall and runs 15 cm on to the floor. It is a skilled operation and even the best craftsman may have difficulty with angles. For thicker materials, some floor layers make their coving in the workshop in 2-m lengths but each coving is purpose-made for a job. Radius of curvature of coving and skirting shall not be less than 12 .5 cm.

7.5. Finish - After laying and fixing, all traces of adhesive shall be removed from the surface as the Work proceeds within the setting time. Care shall be taken to avoid the severing of adjacent surfaces. The surplus adhesive shall never be allowed to remain longer than 24 hours. The surface may be finished with a wax polish recommended by the manufacturer. Alternatively a coat of emulsion polish may be applied. The joints in case of cork tiles shall be lightly sanded with a fine grade abrasive paper. All traces of adhesives and dirt should be removed and the surface brushed clean. After brushing, the surface shall be wiped with a clean damp cloth to remove any further traces of dust or dirt when dry the surface may then be treated with two coats of concentrated paste wax polish as recommended by the manufacturer.

7.6. Protection - When laying and finishing are completed, the flooring shall be protected with hardboard or other sheeting till completion of the building.

8. Maintenance

8.1. General - A period of at least seven days should elapse after installation of the flooring before the start of the maintenance work. During this time the flooring shall be covered and protected from the effect of other contract work in progress in the site. Preventive measures are essential part of flooring maintenance and since dirt and dust are mainly trafficked into a building from the outside it is important to remove these materials by use of dust retaining mats at all door entrance extending to the full width of the door and of sufficient length. The practices stated below should be avoided:

(a) Incorrect use of cleaning agents,(b) Application of polishes and seals on dirty and wet surfaces, (c) Attempts to build up high thickness of polish or seal by reducing the number of applications, and (d) Excessive use of water.

8.2. Linoleum sheet or tiles - The linoleum sheet or tile surfaces shall be swept clean preferably using a mop sweeper and then washed with a cloth dampened with an aqueous solution of neutral detergent. When dry the surface shall be buffed using suitable pad and two coats of dry bright water-based emulsion polish shall be applied. The surface shall be regularly maintained by sweeping, washing with neutral detergent solution, followed by polishing with a coat of water-based emulsion polish.

8.3. If the traffic is light, the floor shall be given frequent brushing, regular polishing and an application of new polish every three to six weeks. Under moderate traffic conditions, the floor shall be given an occasional wash with a wet mop but no detergents shall be used so that the polish is not removed. Application of polish shall be done every one to three weeks.

Linoleum should not be over waxed; when this condition develops, the coatings should be cleared off with white spirit or paraffin and a light even coat of polish or two of liquid dressing applied. When the linoleum has been polished, it will remain bright for a considerable period if a dry mop is applied each day. It is this daily 'dry polish' rather than the frequent application of polish itself that maintains the glossy surface. After exceptional heavy traffic, the linoleum should be swept with a hair broom, rubbed with a mop or cloth frequently rinsed in clean water, and finally rubbed dry. Washing is seldom necessary more than once every three or four months, when only mild soaps or soaps less detergent should be used. Exceptionally heavy dirt may be removed with a cloth soaked in paraffin.

8.4. Cork tiles - The cork tiles shall be swept with a mop and then cleaned with a cloth dampened with an aqueous solution of neutral detergent and allowed drying. Apply a thin and even coating of solvent-based liquid wax. When dry the surface shall be buffed using a fibre brush and a further coat of solvent based liquid wax shall be applied. The cork tiles shall be regularly swept and dry buffed frequently, when necessary the surface shall be cleaned with solvent-based wax remover and rewaxed.

Annexure: 14-A.9

SPECIFICATIONS FOR RUBBER FLOORING MATERIALS FOR GENERAL PURPOSES

(Extract of IS: 809-1992) (Clause 14-37.3.)

1. Scope - This annexure lays down the composition, minimum requirements, workmanship and

prescribes tests  for rubber flooring material suitable  for covering floors of domestic and public  buildings, cinemas,  hospitals,  large stores,  ships,  transport  vehicles,  etc.  This standard does not cover the requirements for special types of rubber flooring used for electrical insulating purposes, conductive or antistatic flooring or rubber flooring having chemical and oil-resistant properties.

2. References - The Indian Standard listed in are necessary adjuncts to this standard.

3. Composition

The flooring shall be made from a compound of natural or synthetic rubber which may also contain reclaim rubber and suitable fillers. All colouring matter shall be of good quality, insoluble in water, resistant to alkalies and direct sunlight or artificial light.

Suitable cotton sheeting shall be used as backing.  The cotton sheeting shall be impregnated with a  high   grade  rubber compound. The Hessian used for the backing shall conform to Type II Hessian as specified in IS: 2818(Part 2)-1971. The Hessian shall be impregnated with a high grade rubber compound.

4. Workmanship

4.1. Appearance - The rubber flooring material shall be of first class workmanship, satisfactorily vulcanized, free from Sulphur bloom and objectionable odour and blisters, cracks and embedded foreign matter to the extent that it complies with the intended design. There shall be no porosity on the surface or throughout the thickness of the sheet. The surface finish of the flooring shall be either glossy or mat. The base stratum may be of any colour.  The underside of the floor covering shall be either furnished with a cloth impression or be buffed smooth. The edges and ends shall be cut true and square.

4.2. Colour -  The colour of the flooring shall not be permanently affected by cleaning with water and a washing soap or by treatment with a suitable floor polish. The colour of the flooring shall not bleed into an adjacent piece of rubber.

5. Dimension

5.1. Thickness - The nominal thickness of the rubber flooring shall be one of the following:

3 mm, 4 mm, 5 mm, 6 mm

For all flooring the overall thickness when measured in the manner described in Annex B, shall not differ from the declared nominal value by more than 0-3 mm at any of the twenty measuring points.

If cloth / Hessian marking is present, the thickness of the flooring shall also be measured, using the apparatus described in Annex B, at three measuring points taken at one end of the roll. The cloth / Hessian marked side shall then be buffed down until the work just disappears. After buffing, the thickness at any one of the three measuring points shall not differ from the original un-buffed thickness at the respective point by more than 0-6 mm.

5.2. Tile sizes and squareness - Rubber flooring, when supplied in the form of tiles, shall be of any thickness (in the case of ribbed or fluted rubber flooring, the thickness refers to the thickness of the base) specified in 5.1 and of the following sizes:

200 mm x 200 mm, 300 mm x 300 mm, 500 mm x 500 mm

The length of side shall not vary from the nominal value by more than 0.15 percent when tested according to the method described in Annex C. There shall be no gap greater than 0.15 mm between any side of the tile and the arm of the jig when the tile is tested according to method described in Annex D.

5.3. Sheet width - Sheet material shall have one of the following widths: 0.9 m, 1.2 m, 1.5 m, 1.8 m, 2.0 m, and 2.1 m

The width of the sheet at any point shall not be less than the nominal value, and shall not exceed the nominal value by more than 6 mm.

The sponge-backed rubber flooring shall have a wearing surface of solid rubber at least 3 mm thick on a sponge rubber base of 3 mm thickness.

6. Performance requirements

6.1. Hardness - The hardness when tested in accordance with IS: 3400(Part 2)-1980 shall be neither less than 65 IRHD (International Rubber Hardness Degree) nor greater than 96 IRHD.

6.1.1. Tolerances on hardness -The tolerances on nominal hardness shall be as described below.

Tolerance in hardness

Nominal Hardness IRHD

Tolerances on hardness IRHD

65  to  76

±5

Over 76  to  86

±4

Over 86  to  96

±3

6.2. Water absorption - The rubber sheets and tiles shall not absorb water by weight more than 0.5 percent of the original weight when tested in the manner described in Annex E.

6.3. Compression set - The compression set shall not exceed 15 percent when test pieces in new condition and test pieces in new condition aged in accordance with Annex F are tested in the manner described in IS: 3400 ( Part 10 )-1977, the duration and temperature for the test being 24+0 hours and 27±1°C respectively.

The test pieces shall show no sign of cracking after the test is conducted. 6.4 Resistance to Abrasion

(Optional) When tested in accordance with IS: 3400 (Part 3)-1987 the abrasion resistance shall be as agreed between the purchaser and the supplier.

7. Packing and marking

7.1. Packing

Rubber flooring sheets shall be wrapped on spool of suitable, dimensions with the backside of the sheet in contact with the barrel of the spool.

Rubber tiles shall be wrapped in Hessian cloth and packed in wooden crates. The extreme end tiles shall be faced back to avoid damage to the surface of the tile. The dimensions of wooden boxes shall be as given below.

Size of wooden boxes containing rubber tiles

Size of rubber tiles

500 x 500 mm

300 x 300 mm

200 x 200 mm

Inside dimensions of wooden box

530 x 530 mm

330 x 330 mm

230 x 230 mm

7.2. Marking - Unless otherwise specified, each sheet, roll or tile shall be legibly and indelibly marked with the following:

(a) Indication of the source of manufacture; (b) Thickness, width and length of sheets and rolls, and thickness and size for tiles; and (c) Year of manufacture.

The flooring sheets, rolls or tiles may also be marked with the Standard Mark.

8. Sampling and criteria for conformity - Representative samples for various tests shall be drawn according to the method and scale of sampling described in Annex G. The criteria for conformity for sheets and tiles shall be in accordance with Annex G.

9. List of referred Indian standards (Clause 2)

IS. No.

Title

180-1984

Specifications for cotton sheeting (second revision)

2818 (Part 2)-1971

Specifications for Indian Hessian: Part 2 305 and 229 g/m2 at 16 percent contact regain (first revision)

3400 (Part 2)-2003

Methods of test for vulcanized rubbers: Part 2 Hardness (first revision)

3400 (Part 3)-1987

Methods of test for vulcanized rubbers: Part 3 Abrasion resistance using a rotating cylindrical drum device (first revision)

3400 (Part 10)-1977

Methods of test for vulcanized rubbers: Part 10 compression set at constant strain (first revision)

4905-1968

Methods of random sampling

10. Measurement of thickness (Clauses 5.1)

10.1. Apparatus - Carry out thickness measurements by means of a dial micrometer gauge, capable of reading to the nearest 0.02 mm, the foot of which exerts a pressure of the rubber of not less than 0.01 N/mm2 and not more than 0.021 N/mm2

10.2. Procedure - Proceed according to 10.2 as appropriate.

For sheet, materials measure the thickness at twenty scattered points along the edges and ends of the roll. For tiles, take the five tiles in the sample and for each tile measure the thickness at four scattered points.

11. Measurement of size of tiles (Clause 5.2)

11.1. Carry out the measurement with an instrument capable of measuring to accuracy of 0.02 mm. Measure each tile for length and width at three quarter points in each direction.  The average of the three measurements in each direction shall be regarded as the dimension of the tile in that direction.

12. Measurement of squareness of tiles (Clause 5.2)

12.1. Apparatus - The apparatus shall be an L-shaped metal jig compressing two arms each of length greater than the side of the tile to be tested and of approximately the same thickness, set in shape of a true right angle on a metal base plate. This plate shall be perfectly flat and free from surface defects.

12.2. Number of test piece - Five tiles shall be used for the test.

12.3. Procedure - Place the tiles against the jig, each corner in turn being inserted into the right angle

and one side of the tile held against one side of the Jig with light pressure. Measure any gap between each side of the tile and the other metal arm with a feeler gauge or microscope.

13. Determination of water absorption (Clause 6.2)

13.1. Procedure - The test specimen, 100 mm x 100 mm with clean cut edges, shall be weighed to the nearest mg (P1) and immersed in distilled water at a temperature of 27 ± 2°C for 24 hours. It shall then be removed, superficially dried with filter paper and immediately weighed (P2). The absorption of water expressed as percentage increase in weight shall be computed from the following formula:

 (P2 – P1)

 ------------ x 100

14. Accelerated ageing (Clause 6.3)

Procedure - The test pieces shall be placed in a thermostatically controlled air oven maintained at a temperature of 70 ± 1°C. The specimens in the oven shall be stationary, free from strain, freely exposed to air on all side and not exposed to light. The total volume of specimens shall not exceed 10 percent of the air space of the oven. Air at 70 ± 1°C shall be passed into the oven at a uniform rate, which will ensure that the atmosphere in the oven is completely changed about three times in an hour. The specimen shall be aged in this manner for a continuous period of 240 hours and there after shall be kept for at least 24 hours at 27 ± 2°C in darkness before being tested.

Note: In view of the influence of exposure of samples to light in the course of accelerated ageing all such exposures should be as nearly identical as possible in tests intended for comparison. The preferable practice in all tests is to protect samples as completely as possible from the earliest moment against exposure to light.

15. Sampling and criteria for conformity of rubber flooring materials (Clause 8.1)

15.1. All the sheets or tiles of the same type and thickness and from the same batch of manufacture shall be grouped together to constitute a lot.

Each lot shall be tested separately for determining its conformity or otherwise to the requirements of the specification.

15.2. Representative samples for various tests shall be drawn at random from a lot.  The number of sheets or tiles to be selected for the samples shall be in accordance with Tables 1 and 2.   For the randomness of selection of the sample the procedure as laid down in IS: 4905-1968 shall be followed.

15.3. Number of tests and criteria for conformity for sheets

All the sheets selected in accordance with 15.2 shall be inspected for appearance and dimensions.  Any sheet found to be defective for any one or more of the requirements shall be considered as defective. The lot shall be considered having satisfied the requirements of the specification for appearance and dimensions if the number of sheets found defective in the sample is less than or equal to the permissible number of defective sheets given in col. 3 of Table 1.

The lot having been found conforming to the requirements of appearance and dimensions shall be tested for hardness, water absorption and compression set test. For this purpose a number of sheets in accordance with Table 1 from among those which have been found conforming under 15.3. Shall be selected at random. Number of specimens in accordance with relevant methods of tests shall be taken out from each of the sheets and tested for all these requirements.  A sheet shall be considered as defective if the test specimens from the sheet fail to satisfy the requirements of any one or more of the tests. The lot shall be considered having satisfied the requirements. All the sheets selected shall be inspected for appearance and dimensions. Any tile found to be defective for any one or more of the requirements shall be considered as defective. The lot shall be considered having satisfied the requirements of the specification for appearance and dimensions if the number of tiles found defective in the sample is less than or equal to the permissible number of defective tiles given in Table 2 of these tests if the number of defective sheets in the sample is less than or equal to the permissible number of defective given in col. 5 of Table 1.

15.4. Number of sheets and criteria for conformity for tiles - The lot having been found conforming to the requirements of appearance and dimensions shall be tested for hardness, water absorption and compression set tests. For this purpose a number of tiles in accordance with Table 1 from among those which have been found conforming shall be selected at random. Number of specimens in accordance with relevant methods of tests shall be taken out from each of the tiles in the sample and tested for all these requirements. A tile shall be considered as defective if the test specimens from the tiles fail to satisfy the requirements of any one or more of the tests. The lot shall be considered having satisfied the requirements of these tests if the number of defective fifes in the sample is less than or equal to the permissible number of defective given in Table 2.

Table 1 Sample size and permissible number of defective for sheet

No. of sheets in the lot For appearance and dimensions For Hardness, water absorption and compression set tests
No. of sheets to be selected for the sample Permissible No. of defectives No. of sheets to be selected for the sample Permissible No. of defectives
Up to 25 5 0 2 0
26 to 50 8 0 3 0
51 to 100 13 0 4 0
101 to 150 20 1 5 0
151 to 300 32 2 7 0
301 to 500 50 3 10 1

Table 2 Sample size and permissible number of defectives for tiles

No. of sheets in the lot For appearance and dimensions For Hardness, water absorption and compression set tests
No. of sheets to be selected for the sample Permissible No. of defectives No. of sheets to be selected for the sample Permissible No. of defectives
Up to 100 13 0 2 0
101 to 300 20 1 3 0
301 to 500 32 2 5 0
501 to 1000 50 3 8 0
1001 to 3000 80 5 13 0
3001 to 10000 125 7 20 1

Annexure: 14-A.10

SPECIFICATIONS FOR LAYING OF RUBBER FLOORS (Extract of IS: 1197-1970)

Rubber floor coverings are mainly suitable for use in domestic buildings and those of a non-industrial character, such as schools, hospitals, offices, where the traffic is expected to be essentially pedestrian and also in buses and ships.  The rubber floor covering is capable of providing a resilient and noise-free floor surface. It is not possible to be specific about wear resistance of the rubber flooring material, but the life will usually be related to the thickness of the flooring material and to the traffic density. The provision of mats will reduce the amount of abrasive grit carried on to the floor. 

The durability of rubber floor is increased if the material is laid correctly and maintained carefully.

IS: 809-1970* lays down the requirements for rubber flooring materials both in sheet and tile form. This standard which was first published in 1958 is now being revised in view of the experience gained in the use of the material during the past decade. In this revision the method of laying and fixing of rubber flooring has been covered in great detail.

0.2. Flooring made from natural rubber is not recommended in situations where it may come into contact with fat, grease, oil or petrol, as these substances may cause swelling, softening or other deterioration.  To meet such situations, flooring made from various kinds of synthetic rubber may be utilized.

0.3. For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance with IS: 2-1960.  The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard.

1. Scope - This code of practice covers the method of laying of rubber floors, in the form of sheet or tiles either solid or backed with fabric, sponge rubber or plain rubber and their cleaning and maintenance.

2. Terminology - For the purpose of this code, the following definitions shall apply.

Base - The prepared surface on which the rubber flooring is laid.

Screened bed - A bed of mortar or other material applied to sub floor and brought to a defined level.

Sub-floor - A structural floor upon which a base is formed.

3. Materials - Rubber sheets and tiles for flooring shall conform to the requirements of IS: 809-19701.

Bitumen mastic for flooring shall conform to IS: 1195-1968.

The adhesive as recommended by the manufacturer should be used. The manufacturer shall also indicate the precautions to be taken while using the adhesive.

4. Storage - Rubber flooring materials shall be stored in a clean, dry and well-ventilated place not exposed to direct sunlight.

5. General - The flooring shall be of a type and thickness suitable for the conditions of service.  Sheet rubber with sponge rubber backing shall be used where high resilience is required.

Necessary information - For efficient planning and execution of flooring work, detailed data and information as given below shall be taken into account:

(a) Area of floor to be covered; (b) Type and quality of flooring to be laid; (c) Thickness of flooring; (d) Level of the finished floor, relative to a datum; (e) Type of damp-proofing, if any; (f) Type and thickness of screeded bed, if any; (g) Any work consequent upon services passing through the flooring; (h) Type of underlay, if any; (i) Treatment of skirling; j) Treatment of junction with adjacent flooring; and (k) Any dressing or polishing required.

6. Pattern and colour - The pattern and colour of the rubber flooring shall be as specified by the purchaser.  Where the floor is likely to be exposed to direct sunlight, care shall be exercised in the selection of the colour.

7. Sub-floor and base

7. 1. New concrete floors - In the case of newly laid concrete floors in contact with the ground, a damp-proof membrane or a bitumen mastic layer shall be incorporated in the thickness of the floor and it shall be properly connected with the damp-proof course in walls.

Special precautions, such as tanking may be necessary against water pressure and to prevent the entry of moisture into floors below ground level.

7. 2. Existing concrete floors - If the floor surface is not smooth and true, it shall be well hacked to provide key for the screeding. It shall then be brought to an even surface with a screeded bed at least 25 mm thick.

Concrete floors, which are in contact with the ground but have not been damp-proofed, shall be covered with a bed of at least 15 mm thick bitumen mastic conforming to IS: 1195-1968.  Over the bitumen mastic 40 mm thick cement concrete shall be laid.

7.3. New timber floors -Timber floors designed to receive rubber floor covering shall be constructed with tongued and grooved boarding and shall be adequately ventilated to prevent the onset of dry rot.  There should not be any gap between planks, which may permit air to penetrate from bottom and affect the bonding of the rubber flooring material with the timber base.  Where plywood is used as a base, it shall be of the moisture-proof grade.

7.4. Existing timber floors -Timber floors that are badly worn and those that are not smooth and true shall be repaired and brought to an even and smooth surface. Badly worn floors shall be levelled and smoothed with a filling of bitumen mastic or other suitable material and covered with an underlay fixed with an adhesive or covered with plywood.

7.5. Metal floors - In the case of metal floors, the surface of the metal shall be smooth.  Screws, bolts, etc, used in the flooring, shall be of the countersunk type.  Where they project above the surface, the metal floor shall be covered with a base bringing the floor to one level before the rubber flooring is laid on.  The metal floor should be rust free and rust proof coating should be applied before the rubber flooring is laid.

7.6. Before applying any adhesive to the base concrete or mortar, it shall be ascertained that the base is dry.  A recommended method for determination of the dryness of the base is given in 13.

8. Underlay - An underlay shall be used where the base is of timber.  It may also be used when it is necessary to make the flooring quieter, warmer and more resilient.  Underlay shall be of either fibre-based saturated bitumen felt (Type 1) conforming to IS: 1322-1970 or other suitable material approved by the purchaser.

The underlay shall be butt jointed and so laid that the joints are at 45° to the principal joints in the rubber flooring.  The underlay shall be secured by a suitable adhesive except on a timber base in which case it may be nailed.

9. Laying and fixing of rubber flooring - Skilled workers under efficient supervision shall be employed for laying of rubber floors.  The workmanship shall be of a high order.

Before commencing the laying operations, the sub-floor shall be examined for evenness and dryness.  The sub-floor shall then be cleaned with a dry cloth.  The rubber flooring material shall not be laid on a sub-floor unless the sub-floor is perfectly dry (see 7.6).

The layout of the rubber flooring on the sub-floor to be covered should be marked with guidelines.  The rubber flooring shall be first laid for trial without using the adhesive according to the required layout.

The adhesive shall be applied by using a notched trowel to the sub-floor and to the back side of the rubber sheet or tile flooring. When set sufficiently for laying, the adhesive will be tacky to the touch, but will not mark the fingers.  In general, the adhesive will require about half an hour for setting, it should not be left after setting for too long a period as the adhesive properties will be lost owing to dust films and other causes.

Care should be taken while laying the flooring under high humidity conditions so that condensation does not take place on the surface of the adhesive.  It is preferable to avoid laying under high humidity conditions.

The area of adhesive to be spread at one time on the sub-floor depends entirely upon local circumstances.  In case of a small room, adhesive may be spread over the entire area but relatively small areas should be treated in a larger room.

When the adhesive is just tack free, the rubber-flooring sheet shall be carefully taken and placed in position from one end onwards slowly so that the air will be completely squeezed out between the sheet and the background surface.  After laying the sheet in position, it shall be pressed with suitable roller to develop proper contact with the sub-floor. The next sheet with its back side applied with the adhesive shall be laid edge to edge with the sheet already laid and fixed in exactly the same manner as the first sheet was fixed. The sheets shall be laid edge to edge so that there is minimum gap between joints.

The alignment should be checked after laying of each row of sheet is completed. If the alignment is not perfect, the sheets may be trimmed by using a straight edge.

The tiles shall be fixed in exactly the same manner as for the sheets. It is preferable to start laying of the tiles from the centre of the area. Care should be taken that the tiles are laid close to each other with minimum gap between joints. The tiles should always be lowered in position and pressed firmly on to the adhesive.  Care should be taken not to slide them as it may result in adhesive being squeezed up between the joints. Rubber flooring tiles after laying shall be rolled with a light wooden roller weighing about 5 kg to ensure full contact with the underlay. Any undulations noticed on the rubber flooring surface shall be rectified by removing and relaying the tiles after thorough cleaning of the under side of the affected tiles.  The adhesives applied earlier in such places shall be thoroughly removed by using proper solvents and the surface shall be cleaned to remove the traces of solvents used.  Work should be constantly checked against guidelines in order to ensure that all the four edges of adjacent tiles meet accurately.

Any adhesive contaminating the face of the rubber flooring should be removed as the work proceeds, care being taken to avoid smearing of adjacent surfaces.  The surplus adhesive should not be allowed to remain longer than 24 hours. It should be removed immediately from the rubber flooring because, if allowed to remain until hardened, a solvent may have to be used to remove it, which might harm the rubber.  In case a solvent is used care shall be taken so that the solvent does not cause any harm to the rubber.

A minimum period of 24 hours shall be given after laying the rubber flooring for developing proper bond of the adhesive.  During this period, the flooring shall not be put to service.  It is preferable to lay the rubber flooring after the completion of plastering, painting and other decorative finish works so as to avoid any accidental damage to the flooring.

When the flooring has been securely fixed, it shall be cleaned with a wet cloth, soaked in warm soap solution (two spoons of soap in 5 litres of warm water).

In the case of stairs where rubber nosings are to be laid as separate units and these are of a heavier gauge than the tread, the difference in thickness shall be made up in one of the following ways:

a) In the design of the section of the base in the case of new concrete stairs;

b) With a screeded bed if the difference in thickness is greater than 12 mm and with a bituminous mastic if it is 12 mm or less in the case of existing concrete stairs; or

c) With plywood or suitable bitumen mastic in the case of timber floors.

Rubber in sheet form shall not be normally used for the formation of coves and skirtings.  They shall be formed in moulded or extruded rubber-composition units.  The skirtings shall be formed or fixed to cover or mask the joint between the rubber flooring and the wall surface.

10. Cleaning and maintenance - Rubber flooring requires correct care and maintenance if it is to retain its resilience and attractiveness.  In general, exposure to direct sunrays, rain or other atmospheric hazards should be avoided.  To avoid damage and to ensure long and efficient service, instructions given below shall be strictly followed.

Rubber flooring shall be cleaned by the use of soap conforming to IS: 285-1964 and a damp cloth or detergent conforming to IS: 4955-1968.  The following materials shall not be used:

(a) Soft soaps; (b) Soaps containing liquid essential oils namely turpentine oil or pine oil;(c) Soaps containing free alkali; (d) Pastes or powders containing coarse abrasives; (e) Scrubbing brushes; and (f) Petrol benzene, naphtha and similar solvents.

Cleaning of rubber floors shall be carried out as follows:

Remove loose dirt with a soft brush; wash the floor in small sections with a piece of cloth or mop, using a 2.5 percent solution of a detergent. The washing cloth shall be rinsed in clean water-before application and afterwards the dirty water shall be wrung into a separate pail.  Excessive amount of water shall not be used as this may creep between the joints of the rubber floor, and in due course

affect the adhesion of the rubber to the sub-floor.  Dry the floor as completely as possible to improve the sheen. If the floor is extremely dirty, the cleanser may be allowed to remain on the floor for a few minutes, after which the dirt is removed more easily.  If a mechanical washer is used, care shall be taken that the brushes are not too abrasive or the machine itself too heavy, as this may open up the joints in the flooring and allow moisture to seep through.  In districts where hard water only is available, a small quantity of household ammonia may be used, say one part in 30 parts of water, and where it is found that stains cannot be removed by cleaning methods, the manufacturer's instructions shall be sought.

A wax emulsion polish shall be used for polishing rubber flooring. Polishes containing organic solvents, which are injurious to rubber, shall not be used.

Polishing of rubber floors shall be carried out in the following manner:

Ensure that the floor is thoroughly clean, dry and free from oil and greases. Spread the polish lightly and evenly over the surface with a clean pad of cotton or similar material. It is important not to rub into the flooring. A second application shall be made in the same manner, but approximately an hour shall elapse between the applications. Leave the polish to dry for approximately 30 minutes, depending on the atmospheric conditions and the polish employed. Rub gently with a soft dry cloth until a high lustre is obtained. When the polished floor becomes dirty, loose dirt shall be removed with a soft broom and the floor wiped with a piece of cloth moistened with clean and cold water.  No cleanser shall be used, as it will remove the polish.  After some time, depending on traffic conditions, the polish may need renewal. The removal of the polish shall be carried out with a detergent solution in water as before for cleaning.

11. Inspection and testing - The finished floor shall be inspected with regard to:

(a) evenness of the surface, (b) fitting at joints and edges, (c) adhesion to the base, and (d) appearance.

12. Precautions - Rubber floorings are combustible and hence shall not be used where incombustible flooring is required.

When heating mains carrying hot water run under the flooring, the pipes shall be lagged or otherwise insulated to prevent possible failure of the adhesive and a tendency for the flooring to curl up.

When heat radiators are used, they shall be so placed that at least 15 cm clear space is left between the flooring and the face of the radiator.

Rubber flooring surface, if wet, may become dangerously slippery. If floors are likely to be in the wet condition, ribbed or fluted type of flooring shall be used.

Collection of pools of water on the flooring shall be avoided to prevent staining.

Some colours are likely to change in shade or get damaged in other ways when brought into contact with certain materials, such as mineral oils, petrol, methylated spirit, acid and alkali.  Hence consideration shall be given to the conditions of use of the floor on which rubber flooring is to be laid and tests conducted, if necessary, before deciding upon the colour of the flooring.

Scrubbing of rubber floors with strongly alkaline soaps, with detergents not having a soap base or with cleansing agents, or the lavish use of water in washing are injurious; the excessively gritty particles of some cleansing agents tend to roughen the surface, thus making it difficult to clean, and a profusion of water may tend to seep between the joints thus causing the failure .of the adhesive.

Skirting (preferably wooden) of about 20 mm thickness should be provided around the border line of rubber flooring to eliminate possible percolation of water used for the cleaning of rubber floors.

13. Determination of dryness of sub-floors and base (Clause 7)

13.1. General - A mortar base shall be deemed to be sufficiently dry to receive the flooring if a hygrometer shows that the relative humidity of a small volume of air, in equilibrium with the surface of the base but isolated from the air of the room.

13.2. Apparatus - The apparatus consists of a hygrometer carried in a casing winch is adapted to confine a quantity of air on being placed against the surface to be tested.

The hygrometer shall be verified (preferably on the site) by exposure for four hours to (air in equilibrium with) a water surface when it indicates a relative humidity of 100 percent.

13.3. Procedure - Set the instrument in position on the base to be tested.  Allow the instrument to stand in this position for not less than four hours to allow equilibrium to be established.  Then take the reading.  Similarly, take a number of readings, the interval between consecutive readings being not less than four hours.

13.4. Evaluation - The base shall be deemed to be dry when all the hygrometer readings show a value of 80 percent relative humidity or less.

Annexure 14-A.11

SPECIFICATIONS FOR CHEQUERED CEMENT CONCRETE TILES

1. Scope - This Annexure covers Chequered cement concrete flooring tiles.

2. References – The Indian Standards listed in are necessary adjuncts to this standard.

3. Terminology - For the purpose of this standard the following definition and those given in IS 1237: 1980 shall apply.

Chequered tiles – Chequered tiles are cement tiles or terrazzo tiles with the centre to centre distance of chequers not less than 25 mm and not more than 50 mm, the groves in the chequers being uniform and straight with the depth of grooves not less than 3 mm.

4. Materials

Cement – Cement used in the manufacturer of tiles shall be ordinary Portland cement conforming to IS: 269-1989 or rapid hardening Portland cement conforming to IS: 8041-1990 or white Portland cement conforming to IS: 8032-1989 or Portland pozzolana cement conforming to IS: 1489(Part I)-1976 and IS: 1489 (Part 2)-1991.

Aggregates – Aggregates used in the backing layer of tiles shall conform to the requirements of IS: 383-1970.  For the wearing layer, unless otherwise specified aggregates shall consist of marble chips or any other natural stone chips of similar characteristics and hardness, marble powder or dolomite powder or mixture of the two.  Hardeners, if required may also be added.

Pigments - Pigments, synthetic or otherwise, used for colouring tiles shall have durable colour.  It shall not contain matters detrimental to concrete and shall according to the colour required be one of the following or their combination:

a) Black or red or brown pigments

IS: 44-1991

b) Green pigments

IS: 54-1988

c) Blue pigments

or

or

IS: 55-1970

IS: 56-1993

IS: 3574 (Part 2)-2000

d) White pigments

IS: 411-1991

e) Yellow pigments

 or

IS: 50-1980

IS: 3574 (Part 1)-1965

Colours other than mentioned above may also be used.

The pigments shall not contain zinc compounds organic dyes.

Lead pigments shall not be used unless otherwise specified by the purchaser.

5. Manufacture - Chequered cement concrete flooring tiles shall be manufactured from a mixture of cement, natural aggregates, and colouring materials where required, by pressure process.  During manufacture, the tile shall be subjected to a pressure of not less than 14 N/mm2

The proportion of cement to aggregate in the backing of the tiles shall be not leaner than 1:3 by mass.

Where colouring material is used in the wearing layer, it shall not exceed 10 percent by mass of cement used in the mix.

On removal form the mould, the tiles shall be kept in moist condition continuously for such a period that would ensure their conformity to the requirements of this standard.  Tiles shall be stored under cover.

6. Dimensions - The size of chequered cement flooring tiles shall be as follows:

Length mm

Breadth mm

Thickness mm

200

200

22

250

250

22

300

300

25

Note: The thickness shall be measured at two points situated approximately 50mm from the ends on the fracture line of the tile that is tested for wet transverse strength.  The total thickness is the arithmetic mean of these two measurements.

Half tiles rectangular in shape shall also be available.  Half tiles for use with full tiles in the floor shall have dimensions, which shall be such as to make two half tiles when jointed together, to match with the dimensions of the full tile.

7. Tolerances - Tolerances on length or breadth of tiles shall be ± 1 mm.  In addition, the difference in length of side between the longest side and the shorter side in the sample shall not exceed 1 mm.

Tolerance on thickness shall be + 5 mm.  In addition the difference in thickness between the thickest and the thinnest tile in the sample shall not exceed 3 mm.

Thickness of wearing layer - The thickness of wearing layer measured from the top of the chequeres shall not be less than 6 mm. The thickness of the wearing layer shall be measured at several points along the fracture line of the tile that was tested for wet transverse strength.  The arithmetic mean of the two measurements which yielded the lowest value shall be the minimum thickness of the wearing layer.

8. Special shape and size - Shapes and sizes of tiles other than those specified in 6.1 may be manufactured when agreed upon between the supplier and the purchaser but the depth of the grooves shall not be less than 3 mm.  The tiles shall also meet all the requirements of the standard.

Note: In rectangular tiles, the requirements for the difference in the length of sides as specified in 7.1 shall be applicable both to the length and width of the tiles.

9. General quality - Unless otherwise specified, the tiles shall be supplied with initial grinding and grouting of the upper layer.  The upper layer of the tiles shall be-free from projections, depressions, cracks (hair-cracks not included), holes, cavities and other blemishes.  The edges of the tile may be rounded.

10. Finish - The colour and texture of the wearing layer shall be uniform throughout its thickness.  No appreciable difference in the appearance of the tiles, from the point of view of colour of aggregate, its type and its distribution on the surface of the wiring layer shall be present.

11. Physical requirement - The tests on tile shall not be carried out earlier than 28 days from the date of manufacture.

Flatness of the tile surface - The tiles when tested according to the procedure laid down in 16, the amount of concavity and convexity shall not exceed 1 mm.

Perpendicularity – When tested in accordance with the procedure laid down in 17, the longest gap between the arm of the “square’ and the edge of the tiles shall not exceed 2 percent of the length of the edge.

Straightness – When tested according to the procedure given in 18, the gap between the thread and the plane of the tile shall not exceed 1 percent of the length of the edge.

Water absorption – When tested according to the procedure laid down in 19 the average percent of water absorption shall not exceed 10.

Wet transverse strength - When tested according to the procedure, the average wet transverse strength shall not be less than 3 N/mm.2

Resistance to wear – When tested in the manner specified, the wear shall not exceed the following value: a) Average wears 2 mm   b) Wear on individual specimen      2.5 mm

12. Marking - Tiles shall be legibly and indelibly marked on the back with the identification of the source of manufacturer.

13. Packing - The tiles shall be packed according to the usual trade practice and adequately protected.

14. Sampling and criterion for conformity - The consignment of Chequered cement concrete flooring tiles shall be divided into a number of lots in accordance with 14.1.1.  Each lot shall be inspected separately for ascertaining its conformity to the requirements of this specification.

14.1.1. Lot - All the Chequered cement concrete flooring tiles in a consignment which are of same type, shape and size and manufactured by a single manufacturer from identical raw materials, under identical conditions of manufacture shall be grouped together to constitute a single lot.

The sample of tiles for inspection and testing shall be chosen from a lot at random.  For guidance in procedure of random selection IS 4905: 1968 may be referred.

Number of samples and criterion for conformity – For each characteristic the number of sample tiles to be selected form a lot and the criterion for determining the conformity of the lot on the basis of the test results on those samples, shall be in accordance with inspection level I in Table I and AQL 6.5 percent in Table 3 of IS: 2500 (Part I)-1992.

If the sample drawn for testing one characteristic can be utilized for testing any other characteristic, without introducing any prejudice in the test results of the latter, it would not be necessary to take fresh samples for the latter characteristics.

15. List of referred Indian standards (Clause 2)

IS No

Title

IS No

Title

44-1991

Iron oxide pigment for paints (second revision)

1489 (Part 2)- 1991

Portland pozzolana cement: Calcined clay based (third revision)

50 -1980

Lead and scarlet chromes (third revision)

2500 (Part 1)- 2000

Sampling inspection tables:  Part 1 inspection by attributes and by count of defects (second revision)

54-1988

Green oxide of chromium for paints (second revision)

3178-1996

Abrasive emery grain

55-1970

Ultramarine blue for paints (first revision)

3574 (Part 1) -1965

Organic pigments for paints: Part 1 Azoic pigments

56-1993

Prussian blue (iron blue) for paints (first revision)

3574 (Part 2) -2000

Organic pigments for paints: Part 2 Phthalooyanines

269-1989

33 grade ordinary Portland cement (fourth revision)

4905- 1968

Methods for random sampling

383-1970

Coarse and fine aggregates from natural sources for concrete (second revision)

8041- 1990

Rapid hardening Portland cement (second revision)

411-1991

Titanium dioxide, anatase, for paints (third revision)

8042: 1989

White Portland cements (second revision)

1237-1980

Cement concrete flooring tiles (first revision)

 

 

1489 (Part 1)- 1991

Portland pozzolanic cement: Part 1 Fly ash based (Third revision)

 

 

16. Method of determination of flatness of tile surface (Clause 11) - Six full size tiles selected in accordance with clause14 shall be tested in the manner specified in 2 to 4.

The flatness of the tile surface is tested by means of a metal ruler, whose length is not less than the tile diagonal.

For testing surfaces that are concave, the ruler is placed on the surface of the tile along one of the diagonals so that the ruler touches the tile at not less than two points.  The largest gap is measured and the test is repeated along the second diagonal.  The larger gap is the amount of concavity.

For testing surfaces that are convex, the ruler is placed on the surface of the tile along one of the diagonals so that the distances between the ruler and the tile, at the ends of the diagonal, are equal. 

The largest gap is measured between the ruler and tile and the test is repeated along the second diagonal.  The larger gap is the amount of convexity.

17. Method of the determination of perpendicularity (Clause 11) - Six full size tiles selected in accordance with clause 14 shall be tested in the manner specified below.

One arm of a ‘square’, the arms of which are longer than the sides of the tile, is placed along one of the edges of the tile, so that the corner of the ‘square’ touches the corner of the tile.  The distance between the other arm of the ‘square’ and the other edge is measured at the end of the tile.  The test is repeated such that two opposite edges shall be tested.

The largest gap between the arm of the ‘square’ and the edge of the tile shall be reported.

18.  Method for determination of straightness (Clause 11) - Six full size tiles selected in accordance with clause14 shall be tested in the manner specified below.

Two corners of the tile surface shall be connected with a fine thread alongside one of the edges and the largest gap between the thread and the plane is recorded.  The test is repeated alongside each of the other edges.  The gap between the thread and the plain of the tile shall not exceed 1 percent of the edge length.

19. Method for determination of water absorption (Clause 11) - Six full size tiles selected in accordance with clause14 shall be used for the test.  They shall be immersed in water for 24 hours, then taken out and wiped dry.

Each tile shall be weighed immediately after saturation and wiping.  The tile shall then be dried to a constant weight in an oven maintained at 110 ± 50C, cooled to room temperature and reweighed

The water absorption for each tile shall be determined as follows:

Water absorption,

Where M1 = mass in a g of the saturated specimen and

            M2 = mass in g of the oven-dried specimens

The average value shall be reported.

Annexure 14-A.12

SPECIFICATIONS FOR PVC ASBESTOS FLOOR TILES (Extract of IS: 3461-1980)

0.1. PVC floor coverings have been in use in the country for more than a decade.  They provide dust free, noise absorbing, resilient and decorative surface for buildings of various types.   The floor coverings are available in different shades and designs.

0.2. There are two kinds of PVC flooring.  One is flexible which normally available in sheet form, and the other is rigid which available in standard tile sizes.  Flexible PVC covering is suitable for comparatively lighter traffic, either for rigid floors such as concrete and stone flooring or for flexible floors such as timber flooring.  Asbestos PVC flooring tiles are rigid, comparatively more suitable for heavy traffic, and for rigid floors such as concrete and stone flooring.   PVC floor coverings are not suitable for areas and surfaces exposed to sunlight and rain.

0.3. This Annexure is prepared duly incorporating improvements found necessary in the light of the usage of the standard and the suggestions made by the various bodies implementing it.  Experience shows that the modular size of the tiles, which was specified in the earlier version, are not being manufactured in the country.  But the Sectional Committee responsible for preparation of the standard felt that the difficulties experienced by the manufacturers to produce tiles of modular size could be overcome by adjusting the manufacturing practice gradually and with this aspect in view the dimensionally coordinated sizes have been retained.  But due to large consumer demand, the size of tiles, which are actually manufactured, and which form the bulk of current production in the country has also been included.  It has been seen that PVC tiles shrink due to long and short storage and it is due to the volatile matter present in the composition of such tiles.  A larger tolerance on the size of the tiles has therefore been permitted to take into account the presence of such volatile matter. The water absorption, surface spread of flame, and ageing characteristics of the tiles have been found to be not of much help in controlling their quality and as such they have been removed from the present revision. The word ' Vinyl ' which was used in the title as well as in the text of the earlier version has also been deleted since the word is the trade abbreviation of PVC and does not recommend any property of the tiles in particular.   The requirement for deflection and indentation characteristics has also been modified which was felt necessary due to improvements made by the industry.  The fire behavior characteristics of such tiles are being investigated and the requirement would be added in the standard as and when the information is available.

0.4. In the formulation of this standard due weightage has been given to the international co-ordination among the standards and practice l prevailing in different countries in addition to relating it to the practices in the field in this country.

1. Scope - This Annexure lays down the requirements for smooth surfaced homogeneous PVC asbestos floor tiles.

Note: This Annexure does not cover laminated floor tiles and floor tiles having an embossed surface.    

2. Materials - The floor tiles shall consist of a thoroughly blended composition of thermoplastic binder, asbestos fibre, fillers and pigments.  The thermoplastic binder shall consist substantially of one or both of the following: (a) Vinyl chloride polymer, and (b) Vinyl chloride copolymer.

The polymeric material shall be compounded with suitable plasticizers and stabilizers.

Note: Chrysotile type of asbestos is preferable for manufacturing PVC asbestos floor tiles.

3. Dimensions and tolerances - The standard size of the tiles shall be 200 and 250 mm square.

The thickness of the tiles shall be 1.5, 2.0, 2.5 and 3.00 mm.

Note: Tiles of size and shape other than those specified in this standard may be supplied if agreed between the purchaser and the supplier.

The permissible tolerances on the dimensions specified in 3 shall be as follows:

Dimensions

Tolerances mm

On 200 mm

± 0.4

On 250 mm

± 0.5

On thickness

± 0.15

Note: A tolerance on length and width of ± 0.2 percent shall be taken for tiles other than specified in 3. 

The tiles shall be of two grades (see Sl. No. (x) of Table 1)

4. Colour and finish

The tiles shall be plain or mottled.  The colour, finish and mottling shall match a sample agreed by the purchaser and the supplier.  Plain tiles shall have the colour uniformly distributed throughout the tile. Mottled tiles shall have the colour distributed at random throughout the thickness of the tile.

Note - In normal manufacture tiles from different batches may vary somewhat in shade of the colour.  A variation in mottling is characteristic of the material.

5. Physical requirements

The tiles shall conform to the requirements given in col. 3 of Table 1 when tested in accordance with the provisions given in col. 4.

6. Tests

6.1. The tests shall be of three categories as given in 6.1.1 to 6.1.3.

6.1.1. Type tests - Tests carried out to prove conformity to the requirements of this specification.  These tests are intended to check the general qualities and design of the tile.

Table 1 Requirements of PVC asbestos floor tiles

Sl. No.

Characteristic

Requirement

Method of test, ref to relevant clause  of IS: 3464-1986

i

Squareness

Gap between the sides of the tile and the arms of the metal jig shall not be greater than 0.15 mm for last 50 mm towards the farther end from the junction of the arms

4

ii

Dimensional stability

Change in any linear dimension shall not exceed 0.25 percent

5

iii

Colour fastness to daylight

Shall not be inferior to that of No.5 of the 8 standard patterns of the blue dyed woollen fabric specified in IS: 686-1985

6

iv

Volatile matter

Loss in weight shall not exceed 1 percent

7

v

Curling

Shall not exceed 0.75 mm

8

vi

Indentation

 

9

a

At 27 ± 20C

Average indentation at the end of one minute shall not exceed 0.38 mm and no individual reading shall deviate from the average by more than 0.05 mm.  In relation to the one minute indentation figures, the average indentation at the end of 10 minutes shall not exceed the value given in Table 2 and no individual reading shall deviate from the average by more than 0.05 mm

 

b

At 46 ± 20C

Average indentation shall not exceed 0.82 mm and no individual reading shall deviate from the average by more than 0.05 mm

 

vii

Residual indentation

Shall not exceed 0.15 mm

10

viii

Resistance to various substances (see Note)

After immersion in various substances and when tested the width of the scratch on the surface shall not exceed 3 mm.  The colour of the treated test piece shall show no significant change when compared with the untreated test piece

11

ix

Deflection

Shall deflect at least 25 mm without breaking

12

x

Impact

Grade A type shall not suffer a fracture and Grade B type shall not break but may contain a crack extending within a circle of 40 mm radius around the point of impact

13

xi

Abrasion resistance

To be agreed between the purchaser and the supplier

20

Note: This requirement is related to the situation of use and the purchaser shall specify the substances to which PVC asbestos floor tiles shall have resistance when tested by the method given in IS: 3464-1986.

Table 2 Indentation limits at 27 ± 20C

[Table 1, Item 6(a)]

Indentation at one minute

Corresponding maximum indentation at ten minutes

mm

mm

0.18

0.27

0.20

0.31

0.23

0.35

0.25

0.38

0.28

0.41

0.30

0.44

0.33

0.47

0.36

0.50

0.38

0.52

6.1.2. Acceptance tests - Tests carried out on tiles selected from a lot for purposes of acceptance of the lot.

6.1.3. Routine tests - Tests carried out on every tile to check the requirements, which are likely to vary during production.

6.2. Categories of tests

6.2.1. Type tests - The following shall comprise the type tests (see 6.1.1):

(a) Colour and finish, (b) Dimensions and tolerances; (c) Squareness, (d) Dimensional stability,(e) Deflection,(f) Impact, (g) Colour fastness to daylight, (h) Volatile matter,(i) Curling,( j) Indentation,(k) Residual indentation, and (l) Resistance to various substances.

6.2.2. Acceptance tests - The following shall comprise the acceptance tests (see 6.1.2).   Acceptance tests shall be carried out on samples selected from each lot in accordance with the sampling procedure detailed in Appendix A:

(a) Dimensions and tolerances, (b) Squareness, (c) Dimensional stability, (d) Deflection, (e) Impact, and (f) Indentation.

6.2.3. Routine tests - The test on colour and finish shall comprise the routine test (see 6.1.3) and shall be carried out on every tile.

7. Packing

The tiles shall be packed in cardboard or corrugated boxes.  Each box shall be marked with the following information:

(a) Name of the manufacturer or his trademark, (b) Size and thickness, (c) Manufacturer's batch number, and (d) Quantity in m

8. Marking

Tiles shall be legibly marked on the back with the name of the manufacturer or his trade-mark and manufacturer's batch number.

Each box may also be marked with the ISI Certification Mark.

Note: The use of the ISI Certification Mark is governed by the provisions of the Indian Standards Institution (Certification Marks) Act and the Rules and Regulations made there under. The ISI Mark on products covered by an Indian Standard conveys the assurance that they have been produced to comply with the requirements of that standard under a well-defined system of inspection, testing and quality control which is devised and supervised by ISI and operated by the producer.  ISI marked products are also continuously checked by ISI for conformity to that standard as a further safeguard. 

Details of conditions under which a licence for the use of the ISI Certification Mark may be granted to manufacturers or processors, may be obtained from the Indian Standards Institution.

APPENDIX A

SAMPLING AND CRITERION FOR CONFORMITY

A-1. Lot - All the tiles of the same type, size and from the same batch of manufacture, in one consignment shall constitute a lot.

A-2. Selection - The number of the tiles to be selected at random from the lot shall depend upon the size of the lot and shall be in accordance with col 1 to 4 of Table 3.

The tiles shall be selected at random from the lot, and in order to ensure the randomness of selection, random number tables may be used. In case random number tables are not available, the following procedure may be adopted for the selection of tiles.

Starting from any tile in the lot count them as 1, 2, 3, …r and so on in one order.  Every rth tile thus counted may be selected till the requisite number of tiles for the sample is obtained, r being the integral part of N/n, where N is the number of tiles in the lot and n is the number of tiles to be selected in the sample.

Table 3 Sample size and criterion for conformity

No. of tiles in the lot

Sample

Sample size

Cumulative sample size

Acceptance number

Rejection number

Up to 300

First

13

13

0

2

Second

13

26

1

2

301 to 500

First

20

20

0

2

Second

20

40

1

2

501 to 1000

First

32

32

0

3

Second

32

64

3

4

1001 to 3000

First

50

50

1

4

 

Second

50

100

4

5

3001 and above

First

80

80

2

5

Second

80

160

6

7

A-3. Criterion for conformity - The number of tiles in the first sample (see col. 2 and 3 of Table 3) shall first be subjected to the acceptance tests (see 6.2.).  If in the first sample the number of defective tiles, that is, those failing to satisfy anyone or more of the acceptance tests is less than or equal to the corresponding acceptance numbers ( col. 5 of Table 3 ), the lot shall be considered as conforming to the requirements of the acceptance tests.  If the number of defective tiles in the first sample is more than or equal to the corresponding rejection number r (col. 6 of Table 3), the lot shall be considered as not conforming.  If the number of defective tiles in the first sample lies between the corresponding values of a and r, a second sample (see col. 2 and 3 of Table 3), shall be selected and subjected to the acceptance tests.  If in the combined sample, the number of defective tiles is less than or equal to the corresponding acceptance number a, the lot shall be considered as conforming, and if the number of defective tiles is more than or equal to the corresponding rejection number r, the lot shall be considered as not conforming.

14.37. SPECIFICATIONS FOR SPECIAL FLOORS AND FLOOR COVERINGS

General - The following Indian Standards cover the use of various types of special floors and floor coverings

(a) Magnesium oxychloride composition floors – IS: 658-1982. (b)Bitumen mastic flooring – IS: 1196-

1978. (c ) Rubber floors – IS: 1197-1970 (See Annexure 14 A.10) (d) Linoleum floors – IS: 1198-1982 (See Annexure 14 A.8) (e) Chemical resistant mortar, Silicate type – IS: 4441-1980.(f) Chemical resistant mortar, Sulphur type – IS: 4442-1980 (g) Chemical resistant mortar, Resin type – IS: 4443-1980 (h) Epoxy resin floor toppings – IS: 4631-1986 (i) Flexible PVC sheet and tile flooring – IS: 5318-1969 (j) Parquet flooring – IS: 5389-1969 and IS: 9472-1980.

14.37.1. Magnesium oxychloride composition floors

14.37.1.1. General - Magnesium oxychloride composition consisting of mixture of calcined filler and pigments provides a good floor if proper ingredients are mixed in correct proportions and skilled labour is employed in laying the floor.  Too wet a mix with excess magnesium chloride results in sweating of the floor surface.  Mineral oils, greases or vegetable oils do not affect the floor.  The flooring is not seriously affected by alkalis, but strong alkalis, such as, soda or harsh cleaning agents tend to attack the protective dressing and thus exposing the flooring to action of water.  However, the finished floor tends to be protected from excessive water or moisture by periodic applications of wax – polish or oil at regular intervals.

Magnesium oxychloride flooring should not be used in any situation where it would be exposed to damp conditions for long periods, unless other suitable protective measures are taken; it should not be used in places where it will be exposed to acids or salts continuously.

14.37.1.2. Types

a)  General purpose floor (Trowel finish) – This type of floor shall contain an adequate amount of calcined magnesite,  fillers such as, talc, saw dust and asbestos ; and fine aggregates which with magnesium chloride of suitable strength make a product which may be trowelled to a dense smooth glossy finish.  The composition may be applied monolithically. It has wearing properties which make it adaptable for service conditions in offices, ship decking, railway carriages, hospital rooms and wards, residential and industrial floors.

b)  Heavy duty floor (Trowel finish) - This type is closely related to the general purpose floor.  The principal difference is that the quantity of fillers used in minimum and the proportion of aggregates is increased, the aggregates being of hardness similar to crushed granite.  It is adapted for special service conditions in industrial and restaurant kitchens, light industrial plants, corridors, lobbies and business establishment having the large usage.

c)  Non-spark static discharging floor (Trowel or ground finish) – This type of floor is similar to heavy duty floor except that the aggregates used are not siliceous and do not contain materials which will produce a spark when struck with any object.  This type of floor is suitable for hospital operation theatre, ammunition and chemical plants or other areas subject to explosion hazards.

d)  Non-slip floor (General purpose) – This type of floor is similar to heavy duty floor except that certain proportion of the aggregates is of abrasive type.  This floor is specially adaptable to areas, such as, entrance lobbies, ramps, stair treads, landings, etc.

e)  Mosaic or Terrazzo floor (Ground finish) – The matrix in this case is the same as in general purpose, non-sparking or non-slip floors but the aggregate used in marble chips with each 100 kg of the dry mix, 125 to 200 kg of coarse aggregate is used.  The floor is adaptable for places where a highly decorative effect coupled with wear resistance is required.

f)  Industrial granolithic floor – This type of floor is essentially the same as mosaic or terrazzo floor in which the matrix is the same as in the heavy duty floor and the coarse aggregate consists  of granite chips or similar hard stone chips.  With each 100 kg of dry mix, 200 to 225 kg of coarse aggregate is used.  This type of floor is recommended for the most severe and abrasive service conditions.

g)  Base coat – This type has the maximum resilience and is employed as a light-weight base for the types of oxychloride floors as mentioned.  Two sub-types are generally employed

Sub-type: 1 – General purpose base coat, and Sub-type: 2 – Heavy duty base coat.

14.37.1.3. Materials

a) All materials used in the manufacture of magnesium oxychloride floor finish should comply with IS: 657-1982. The test limits for calcined magnesite in this standard are based on a notional mix of calcined magnesite and saw dust gauged with magnesium chloride and do not obviate the need to check compliance with IS 658-1982.  Materials for magnesium oxyflouride composition floors shall be supplied in two parts namely, dry mix and magnesium chloride.

b) Dry mix

1) Dry mix for all types of floors – The dry mix shall consist of an intimately mixed composition of dry ingredients.  If talc is used as filler it shall not exceed 5 per cent by weight of dry mix.

2) Dry mix of non-spark static discharge floors – The dry mix for non-spark static discharging floor shall contain only such materials in its composition which are free from substance capable of producing a spark when struck or abraded with a steel tool.

3) Dry mix for non-slip floor – About 35 per cent  by weight of the aggregates used in the dry mix for non-slip floors shall be of non-rusting natural (emery) or manufactured (fused alumina) product, the particles of which are of irregular shape and of slightly open texture.

14.37.1.4. Properties of magnesium oxychloride floors

  1. Magnesium oxide floor should not be exposed to action of sea water; and is not recommended where it may be exposed to high humidity or damp conditions; damp proof course should be incorporated if the base is in direct contact with the ground.
  2. Floor finish should be selected by sample size of 300 mm x 300 mm x 20 mm which finished work should conform in hardness (as per IS: 658-1982) near to colour, texture, number and thickness of coats.

c)  Resistance to chemical attack

  1. The floor finish, if not adequately protected by oiling or waxing gradually disintegrates under continuous exposure to water.
  2. The floor finish is not affected by alkalis but strong alkalis such as soda or harsh cleaning agents attack the protective dressing and exposure the floor finish to the action of water.
  3. The floor finish is subject to attack by acids.  Adequate protection against occasional contact with dilute acids may be obtained by oiling or waxing.
  4. The floor finish is subject to attack by continuous exposure to salts; under normal conditions of use, some protection may be obtained by oiling or waxing.
  5. It should not be slippery when treated as described.  Special non-slip surfaces may be obtained by incorporating abrasive grit in the floor finish.
  6. Sweating of magnesium oxychloride floor finish is characterised by beads of magnesium chloride solution forming on the surface in humid atmospheres and is not merely the result of the condensation of moisture on a cold surface.  The tendency to sweat is inherent in the material, since magnesium chloride takes up readily moisture from damp air.
  7. If the ingredient of the floor finish mixes with free lime tends to cause expansion. The floor finish is likely to crack or lift if laid on light weight concrete base or on a dense screed which not firmly bonded to the base.
  8. The thickness of floor finish shall be not less than 10 mm.
  9. Contamination of the floor finish mixes with free lime tends to cause expansion.  The floor finish is likely to crack or lift it laid on light weight concrete base or on a dense screed which h is not firmly bonded to the base.
  10. Coves and skirtings can be formed with magnesium oxychloride finishing material.  Contact between the oxychloride mix and the wall plaster should be avoided by the use of an intervening fillet of wood or other suitable material. Sand cement rendering on the wall surface is desirable as a backing.
  11. Metalwork, such as, partitions, or gas, water and electrical services in contact with a magnesium oxychloride floor finish is liable to corrode and should be isolated from the floor finish, by not less than 25 mm of uncracked dense concrete or protected by a coating of bitumen or coal tar composition or by a suitable material.

14.37.1.5. Application

14.37.1.5.1. Preparation of the base - The base shall be rigid, sound, free from rising damp and not unduly porous.  Highly absorbent materials, such as, pumice concrete, breeze or clinker concrete and aerated concrete shall not be used unless a layer of damp-proof course is laid between the base and the main floor.

a)  New cement concrete base – The base shall be true and even and slightly coarsened by stiff brush or broom.  A steel trowel finish is not desirable.  The cover to steel of base concrete shall not be less than 25 mm, since the reinforcement would be damaged by magnesium oxychloride compound.  New concrete should age for 28 days before receiving the flooring.  No lime admixture shall be allowed in concrete.

b)  Existing concrete base – The existing concrete base should be roughened to a suitable degree by chiseling, picking or by any other suitable process before oxychloride composition is laid.  Absorption may be checked and if porous screed may be spread on the base.

c) Timber base – A suitable mechanical key should be provided between timber base and floor finish, such as dovetailed wooden battens or galvanized wire netting firmly screwed to the base at approximately 200 mm centre.  An equal number of galvanized clout nails should be used at 200 mm centres and be left proud of the base.

14.37.1.6. Preparation of floor finish mixture - Magnesium chloride both before and after it is dissolved should not be allowed to come into contact with any floors and walls.   The solid chloride should be broken up and dissolved in water tight vessel by covering the same with clean water, that is, clean and free from deleterious acids, alkalis, salts or organic material and stirring the same from time to time.  The solutions should be allowed to stand over night so that the residue, dust, impurities, etc, may settle to the bottom.  The clean concentrated solution shall be well stirred after each dilution.  The solution shall be prepared sufficiently early so that it is cooled to room temperature before use.  The specific gravity of the solution should be maintained at the value selected from the table given below.  This value will depend on the type given of work, the nature of the base and ambient and temperature conditions.

Floor finish mix

Baume (BE) scale

Specific gravity

Single coat and top coat

20 degree to 24 degree

1.16 to 1.20

Bottom coat, coves and

Skirtings

18 degree to 20 degree

1.14 to 1.16

14.37.1.7. Proportions of dry materials - The proportions of dry materials may be varied within certain limits in order that the properties of the finished product may be suited to the conditions of use.  Proportions shall be by weight and the dry material should be thoroughly mixed by machine.

a)  Proportion of chloride solution – A strong floor finishing material may be formed by addition of any sufficient magnesium chloride solution to make the dry mixed materials damp.  For single coat and top coat some additional solution is usually required to enable the mix to be placed and brought to a smooth finish.  The extra chloride does not improve the strength of the mixture and the use of excessive amount will have harmful effects.

b)  The amount of solution required for a given weight of dry mix cannot be stated accurately; however, the following guidelines may be used;

1)  Bottom coat floor finish mixes – Bottom coat finish mixes should be gauged to a damp but not plastic consistency; just sufficient solution should be used to enable the mix to bind together when thoroughly compacted by tamping.  As a guide, a mix from which liquid can be squeezed by hand should be considered as suitable.

2)  Bottom coat mixes for coves and skirtings – These mixes should be gauged to a consistency just sufficiently plastic to allow the mix to be spread on the wall.

3)  Single coat and top coat mixes – These mixes should be gauged with no more solution than is needed to produce a stiff mix which is just sufficiently plastic to be spread with a trowel.

14.37.1.8. Final mixing - The final mixing of the chloride solution with the dry mix shall be done in a container and not on the floor.  The quantity of mix should be sufficient to be laid in one batch before it sets; no solution should be added during laying.  If the mix is too stiff it should be discarded.

14.37.1.9. Laying the floor finish

  1. Size of bay will depend on the temperature conditions generally; the controlling factor would be the time taken to obtain adequate compaction of the floor finish.
  2. Joints shall be provided if the floor dimensions are more than 5 m in either direction.  The joints may be mastic insertions or strips of hardwood, vulcanite, non-ferrous metal or other suitable material, 5 mm wide, bedded flush with the surface of the flooring material.  These joints should coincide with the joints of the base, if any.
  1. The concrete base should be dampened before laying; excessive flooring should be avoided. The dampening should be done either with a solution of magnesium chloride which should not be weaker than 12 degree BE nor stronger than 14 degree BE; or a wash composed of a 14 degree BE magnesium chloride solution and magnesia mixed to the consistence of cream and brushed over the base.
  1. If a thickness of 40 mm or more is required, additional coats may be laid, each of which should not be more than 20 mm thick.
  2. For skirting on sand cement rendering, the mix may be applied in a single coat not less than 5 mm thick; then the backing is un-rendered. The mix should be applied in two coats to a total thickness of not less than 15 mm.
  3. Each coat should be thoroughly compacted ensuring no formation of laitance.
  4. When the top coat has hardened sufficiently, its surface shall be felt finished after trowelling. Scraping shall be undertaken on ornamental work such as mottled finishes.

14.37.1.10. Curing - Rapid drying of floor shall be avoided at least for 24 h after laying the floor.

It should be allowed to set and harden at least for 3 days before opening it to traffic.  It should not be allowed for heavy traffic for some weeks till it is fully dried and hardened.  During hardening it should not be exposed to sun or rain.

14.37.1.11. Surface treatment - The floor finish should be washed with clean warm water changed frequently and wiped dry at regular intervals until the efflorescence has ceased. At this stage the finish may be treated with a mixture of linseed oil (double boiled) (see IS: 77-1977) and turpentine (see IS: 533-1973) in equal volumes or with a suitable wax or drying oil.  For mottled floor finish, the finish

should be laid in two coat work.

14.37.1.12. Testing - Testing shall be carried out on samples mixes from three different parts of the vessel.  The tests should be done as per IS: 658-1982.

14.37.1.13. Maintenance - The floor surface shall be cleaned with warm water only.  Mild house soap free from alkali may be used occasionally; but strong household cleaning powders, soda, etc., should not be used.

14.37.1.14. Protection of metal work - Metal work may receive anti-corrosive treatment; suitable materials are bituminous coal tar composition with or without added fillers, intended for hot application.  For cold application a solution of bitumen or of coal tar in a volatile solvent with or without added fillers but excluding bituminous paints with drying oils may be used.

14.37.2. SPECIFICATIONS FOR BITUMEN MASTIC FLOORING

14.37.2.1. General - Bitumen mastic is a dustless, odourless, joint less flooring and impervious to the transmission of moisture, either in liquid or vapour form.  The surface is easily cleaned, noiseless under traffic conditions and resilient. While it may carry heavy loads, application of concentrated point loads may cause indentation.  Bitumen mastic is, therefore, suitable for a variety of uses under a wide range of climatic and service conditions, except as detailed below

a) The surface of bitumen mastic is liable to become gradually softened by prolonged contact with greases, fats and oils.  Contamination with such materials shall be avoided.

b) Susceptibility of bitumen mastic floor finishes to chemical attack is given in Table below

Susceptibility of bitumen mastic floor finishes to chemical attack

Sl.No.

Agency

Susceptibility to attack

1

Acids and vegetable extracts

Normal grades subject to attack by acids, special grades can withstand attack by dilute solutions.

2

Alcoholic liquors

Normal grades are subject to attack by certain alcoholic liquors. Special grades may be used in breweries and distilleries.

3

Alkalis

Not affected by low concentration alcoholic solutions.

 

 

Alcoholic solutions above 38 degree C will affect.

4

Brine (sodium and calcium chloride) and sulphate salts

Unaffected under normal circumstances

5

Complex industrial liquors

Conduct tests to choose the grade of bitumen mastic.

6

Radio active materials

Special grades of bitumen

are used.

7

Dairy products and milk

Normal grade where hygienic conditions are maintained (see Part 3)

8

Mineral, animal and vegetable oils, fats and greases.

Subject to attack

9

Sugar syrup, sugar

Unaffected by low concentration sugar solutions syrup, molasses, etc. will affect at all temperatures.

10

Water

Unaffected unless the water is hot, for which high temperature mastic may be used.

14.37.2.2. Materials

a) Bitumen mastic shall conform to the requirements given in IS: 1195-1978.

b) Special types of metal armoring may be incorporated in bitumen mastic flooring for industrial purposes to increase resistance to abrasion (see Part 3).

14.37.2.3. Preparatory work

Base

a) The base shall be adequately strong to receive the bitumen mastic and to carry the anticipated load over it.  The base shall be true, even and dry surface which has been slightly roughened by means of a stiff broom or wire brush and should be free from ridges and hollows.  A steel trowelled finish is not desirable.  The levels of the base should be such that the specified thickness of bitumen mastic may be applied uniformly.

b) The total thickness to which bitumen mastic should be laid depends on the traffic conditions to which the floor will be subjected.

c) Usually bitumen mastic should be laid in one coat, but two-coat work may be used depending on the thickness of floor finish.  As a general guide the thickness given below are recommended.

Light duty      15 mm to 20 mm thick

Medium duty  20 mm to 25 mm thick

Heavy duty    25 mm to 30 mm thick

d) There may be a slope of not less than 1 in 75, in the base, if the finished floor is likely to have water or industrial liquors upon it.  Channels should be provided to ensure adequate drainage.

e) The base may be treated in any of the following ways;

1) A screed bed of cement concrete or lime concrete not less than 25 mm thick;

2) An isolation membrane or underlay or

3) On metal floors, a thin priming coat of bitumen paint applied over a clean and dry surface.  The paint should be dry before the mastic is laid.

Isolating membrane - An isolating membrane conforming to IS: 1322-1993 is normally used where bitumen mastic up to 20 mm in thickness is laid where the base is in direct contact with the ground ; glass fibre felt  (see IS: 7193-1974) may be used as an alternative.  Thickness of bitumen mastic exceeding 20 mm on new concrete is usually laid without an isolating membrane.  Isolating membranes should be laid loose.

Underlay - The underlay, when required, should be laid loose. Remolding of broken bitumen mastic blocks is permitted.

14.37.2.4. Laying

When the material is sufficiently molten to be workable, it should be carried in flat mortar pans, to the point of laying.  To prevent sticking of mastic to the pans, inorganic dust may be sprinkled on the pans. Bitumen mastic should be generally laid in bays of one coat.  It should be spread to the specified thickness by means of hand tools.  Bitumen mastic should then be floated to a uniformly level surface by a heavy wooden float and should be free from roughness and imperfection.  If ‘blowing’ occurs, the bubbles should be punctured and the area affected shall be made good while the mastic is still hot.

Two –coat of single-coat work, but care should be taken to arrange that the joints in successive layers are staggered.

Surface finish

Surface Finish could be either matt finish or polished finish, or as desired.

Immediately after laying, the bitumen mastic shall be protected from damage till it cools to the surrounding temperature.  Bitumen mastic should be allowed for traffic after the material has cooled.  Frequent polishing, should be avoided as it will become slippery.

Bedding - Special care shall be taken to effect proper bond between new and old sections of work.  The contact edges of the previously laid work should be cleaned and warmed by additional applications of hot mastic.  This procedure also should be adopted for joints between the floor finish and skirts and coves or fillets.

Skirting should be executed in not less than two-coat particular care being taken to ensure proper adhesion of the first coat to the base.  Special care shall be taken at external angles to ensure the full thickness of material.

Maintenance - Bitumen mastic surface requires relatively little maintenance.  Superficial dirt may normally be removed by washing with warm water and suitable detergents.  After the dirt is removed, the floor should be mopped with clean water.

Repairs - The correct method, to remove damaged area, is to place hot mastic around and over the area concerned and after this has softened the area concerned, it should be cut away and made good.

14.37.3. SPECIFICATIONS FOR RUBBER FLOORS

14.37.3.1. General - Rubber floor coverings are mainly suitable for use in domestic buildings and those of a non-industrial character, such as, schools, hospitals, offices, where traffic is expected to be essentially pedestrian and also in buses and ships.  It provides a resilient and noise –free floor surface.  The life of rubber floor is related to its thickness, since it is not possible to be specific about wear resistance.  Provision of mats will reduce the amount of abrasive grit carried to the floor.  The durability of rubber floor is increased if the material is laid correctly and maintained carefully.  IS: 809-1992 (Annexure 14 A.9) lays down the requirements for rubber flooring materials both in sheet and tile form. (See also Annexure 14 A.10)

Flooring made of natural rubber is not recommended in situations where it may came into contact with fat, grease, oil or petrol, as these substances may cause swelling, softening or other deterioration.  To meet such situations, flooring made from various kinds of synthetic rubber may be utilized.

14.37.3.2. Preparatory work

Sub–floor and base

a)  New concrete floors – In the case of newly concrete floors in contact with the ground, a damp-proof membrane or a bitumen mastic layer shall be incorporated in the thickness of the floor and it shall be properly joined with the damp-proof course in the walls.  Special precautions, such as, tanking may be necessary against water pressure and to prevent the entry of moisture into floors below ground level.

b)  Existing concrete floors – If the floor surface is not smooth and true, it shall be well hacked to provide key for the screeding.  It shall then be brought to an even surface with a screeded bed at least 25 mm thick.  Concrete floors which are in contact with the ground but have been damp-proofed shall be covered with a bed of at least 15 mm thick bitumen mastic conforming to IS: 1195-1978.  Over the bitumen mastic 40 mm thick cement concrete shall be laid.

c)  New timber floor – Timber floors shall be constructed with tongued and grooved boarding and shall be adequately ventilated to prevent dry set.  There should not be any gap between the planks which may permit air to penetrate from bottom and affect the bonding of the rubber flooring material with the timber base.  Where plywood is used as a base, it shall be of the moisture proof grade.

d)  Existing timber floors – Damaged and worn floors should be repaired and brought to an even and smooth surface; an underlay also may be used.

e)  Metal floors – The surface of metal floors shall be smooth. Screws, bolts, etc, used in the flooring shall be of counter sunk type.  When they project above the surface, the metal floor on level before the rubber flooring is laid on.  The metal floors should be rust free and a rust proof coating should be applied before the rubber flooring is used.

Underlay - An underlay shall be used where the base is of timber.  It may also be used when it is necessary to make the flooring quieter, warmer and more resilient.  Underlay shall be either fibre-based saturated bitumen felt (Type I) conforming to IS: 1322-1993 or other suitable material.

The underlay shall be butt joined and so laid that the joints are at 45 degree to the principal joints in the rubber flooring.  The underlay shall be secured by a suitable adhesive except on a timber base in which case it may be nailed.

14.37.3.3. Laying and fixing of rubber flooring

a) The sub-floor shall be cleaned with dry cloth.

b) The lay out of the rubber flooring shall be first laid on the sub-floor to be covered and should be marked with guidelines.  The rubber flooring shall be first laid for trial without using the adhesive according to the layout.

c) The adhesive shall then be applied by using a notched trowel, to the sub-floor and to the backside of the rubber sheet or tile flooring.  When set sufficiently for laying, the adhesive will be tacky to touch, but will not mark fingers.  In general, the adhesive will set in about half an hour; but it should not be left for too long a period as the adhesive properties will be lost owing to dust film and other causes. It is preferable to avoid laying the flooring under high humidity conditions so as to prevent condensation.  The area of adhesive to be spread depends on the local circumstances; in a small room the area can be covered at one stretch.

d) When the adhesive is tack free, the rubber flooring sheet shall be carefully  taken and placed in position  from one end onwards slowly so that air will be completely squeezed out between the sheet shall be pressed with suitable roller to develop proper contact with the sub-floor.  The next sheet with it backside applied with adhesive shall be laid edge to edge with the sheet already laid so that there is a minimum gap between joints.

e) Alignment should be checked and if not perfect, the sheets may be trimmed.

f) The tiles should be laid in exactly the same manner as the sheet.  Any adhesive contaminating the face of the rubber shall be removed as the work proceeds within 24 h.  A minimum period of 24 h shall be allowed for proper development of bond and no traffic should be allowed.  Thereafter the flooring shall be cleaned with a wet cloth, soaked in warm soap solution (two spoons of soap in 5 1 of warm water).

g) In case of stairs, where rubber nosing are to be laid as separate units and are of heavier gauge, the difference in thickness shall be made up in design, or by screed or with plywood or bitumen mastic.  Rubber in sheet form is not used for coves and skirting; suitably moulded units should be used.

h) Rubber shall not be cleaned by soft soaps, soaps containing essential oils, soaps with free alkalis, pastes or powders containing coarse abrasives, scrubbing brushes or petrol benzene, naphtha and similar solvents.

i) A wax-polish shall be used for polishing rubber floors; polishes containing organic solvents shall not be used.

14.37.4. SPECIFICATIONS FOR LINOLEUM FLOORS

14.37.4.1. General - Linoleum provides a satisfactory floor for residential and public buildings, railway coaches, ships, etc.  It is also suitable for most type of non-industrial floors.  In light industry, such as, electronic industry linoleum may be used, as the risk of damage by cutting, to which linoleum is vulnerable, is small.  However, if it gets wet, it expands and eventually rots.

Linoleum is not suitable for locations subjected to rising damp, external exposure, exposure to traffic with indentations from heels or static loads, and where high polish is required because it becomes slippery.

14.37.4.2. Materials

Flooring material shall conform to IS: 653 -1992. (See Annexure 14-A.7)

Underlay shall be as below;

For timber

Plywood at least 4 mm thick

Sub-floors

Hardboard at least 3 mm thick

 

Fibre based bitumen felt atleast 1 mm thick to IS: 1322-1993

Concrete floors

Bitumen mastic to IS: 1195-1978

Adhesives shall be as per recommendations of the manufacturer.

14.37.4.3. Preparatory work

Sub-floor - Sub-floors should be thoroughly dry before laying of linoleum since entrapped moisture cannot escape.  It should also be even to ensure thorough bonding with the linoleum.

a)  Timber sub-floors – A timber sub-floor should be sound, rigid and dry.  It should be well ventilated to discourage fungal attack.

In case of new constructions, tongued and grooved boarding shall be used.  All nails shall be punched down and timber floor made even.

In existing floors, when it is not possible to obtain an even surface, use of diagonal boarding is recommended, after removing and replacing badly affected boarding; alternatively plywood may be used to get an even surface.

b)  Concrete sub-floor – Concrete sub-floor may be finished as mentioned in Para 2, to give an even and dry surface.  Rising damp may be protected by using bitumen mastic, 15 mm thick, conforming to IS: 1196-1978 as described.

c)  Other sub-floors – They should be dry and even.

14.37.4.4. Laying (See Annexure 14-A.8)

a) Linoleum should be stored at room temperature of not less than 20 degree C for at least 48 h before unrolling; after unrolling, it shrinks in length and expands in width.  When two widths of linoleum are to meet, they shall be left with an overlap until the expansion has stopped and then cut to fit.

b) The linoleum should be laid either loose or fixed to the sub-floor by means of suitable adhesives.  Any priming coat should be allowed to dry before the adhesive is spared. Adhesives should be spread evenly as per manufacturers’ instructions. Naked light should be avoided, if the adhesives having low flash solvent (containing petroleum and naptha) are used.  The area shall be well ventilated and smoking shall be prohibited.

c) The underlay shall be fixed to the sub-floor in such a way that a smooth surface is available.  The finished underlay shall be cleaned of all dirt and dust, chemicals, paints, etc.  The linoleum shall be firmly pressed into the adhesive spread over the underlay.  To ensure good bond, the surface can be rolled with a roller of 70 kg weight, washing from centre to the walls.  If necessary, sand bags may be placed at some points.

When laid on concrete floors it is desirable to prime the back of linoleum with the adhesive.  Cork tiles should be fixed with the adhesive.

Normally 4.5 and 3.2 mm thick linoleum can be used for commercial and institutional buildings respectively; for domestic buildings 1.6 mm thick linoleum may be used.

d) The surface, after cleaning of all debris, etc, may be wax-polished or a coat of emulsion polish may be applied. No traffic shall be permitted till the completion of all related works.

e) All surfaces shall be swept clean and washed with a cloth dampened with an aqueous solution of neutral detergent.

14.37.5. SPECIFICATIONS FOR EPOXY RESIN FLOOR TOPPINGS

14.37.5.1. General - Epoxy resins are suitable for use on industrial floors, such as, in chemical plants manufacturing fertilizers, pharmaceuticals, acids and solvents, in dairy industry, tanneries, breweries, garages, service stations, warehouses, metal plating and pickling areas.  They have good qualities of adhesion and chemical resistance, hardness, abrasion resistance; physical properties, such as, compressive, impact and flexural strength, negligible shrinkage, dimensional stability and adhesion to cured concrete, metals and other surfaces.

14.37.5.2. Materials

(a) Epoxy resin shall conform to IS: 9197-1979,(b) Hardness shall conform to IS: 9197-1979,(c) Accelerator shall conform to IS: 9197-1979,(d) Plasticizers and non-reactive diluents shall conform to IS: 9197-1979, (e)Liquid coal tar shall conform to IS: 9197-1979, and (f) Aggregates shall conform to IS: 9197-1979. ) (See also Annexure 14 A.11)

14.37.5.3. Types of epoxy resin toppings - There are two types of epoxy resin floor toppings :

a)  Trowel type – This is usually heavily filled with sand or other suitable aggregates and the compound is applied by trowel.  Such compounds are often referred to as mortars or screeds. 

b)  Flow type – This is usually a solventless compound containing filler and pigment and the mixture is poured directly on to the surface when the blend will flow and level itself with little assistance to form a smooth continuous coating. 

Terrazzo floors - The Portland cement in conventional terrazzo is replaced by epoxy resin binder.  Such flooring formulations serve the dual purpose of providing a good appearance and chemical resistance. 

Non-skid floors - This type of floor may be prepared by sprinkling a suitable grit on an epoxy resin floor topping when the latter is still in a tacky state. 

The following minimum thicknesses are recommended: trowel type – 4 mm for normal use and 6.5 mm in areas of thermal shock and heavy traffic on horizontal surfaces.

(a) Flow type - 2 mm  (b) Terrazzo floors - 10 mm.

14.37.5.4. Preparatory work

Concrete surfaces shall be properly cured and dried and kept rough.  Laitance shall be removed.  All cracks and broken areas of an existing base shall be sealed, fresh concrete applied and cured.  Grease and oil shall be removed with solvents, such as, acetone or a suitable detergent. 

The concrete surface shall be even.

Mild steel and cast iron surfaces shall be washed with a suitable solvent or detergent solution to remove grease or oil.  The surface shall then be sand blasted or abraded with emery cloth, abrasive disc or with wire brushes. 

14.37.5.5. Laying

Mixing of epoxy resin blend - The mixing shall be carried out at the site as follows:

  1. The constituents required shall be mixed in the correct proportions as specified by the formulator.
  2. Unless otherwise specified, the order of addition of the constituents shall be resin, hardener and aggregate. 
  1. Aggregates, when required, shall be added to the blend in a mixer in dry condition.
  2. The duration of mixing shall be adequate to ensure thorough mixing, the quantity mixed at one time shall be such that a uniform thickness of epoxy resin topping may be applied over the whole floor. 

Application

  1. The blended epoxy resin mix shall be applied uniformly, over the area prepared, to a uniform thickness.
  2. For some areas where heavily filled trowelling compound is to be applied, the prepared area shall be first covered with a tack coat of unfilled resin-hardener mix applied by brush which shall be allowed to cure to a tacky stage. 
  3. Where heavily filled trowelling compound is used, it is advisable to apply a seal coat of unfinished resin to ensure that pores, if any, are sealed adequately.
  4. As mild steel tools are liable to cause stains on light coloured surfaces, it is recommended that stainless steel, chromium on rigid PVC tools should be used after laying of epoxy resin floor toppings.
  5. After application of the epoxy resin topping, the floor shall be allowed to set without disturbance for a minimum period of 24 h.  the floor can be brought to normal use after a period of 7 days at a temperature of 20° C and above though light traffic may be permitted after 24 h of laying the floor topping.  Below 20° C special hardeners may be used as recommended by the formulator in order to obtain proper setting of the floor topping. 
  6. Expansion joints to coincide with those in the base concrete should be provided in epoxy resin toppings.  The expansion joints in the epoxy topping shall be filled with flexible putty that shows appropriate water and chemical resistance as recommended by the formulator. 

Safety precautions - Epoxy resins cause irritation to persons having sensitive skin.  Good ventilation is necessary and the most effective precaution is the use of rubber or polyethylene gloves.  It is preferable to wear thin cotton gloves underneath for comfort.  Other methods recommended are regular washing hands, arms and face with soap and luke warm water followed by thorough drying with a clean towel and the use of a barrier cream.  Splashes on skin should be removed immediately by washing with soap and luke warm water.  On no account should a solvent be used for this purpose. 

Polyamide hardeners should be used where floors are exposed to frequent impact stress and fluctuations in temperature.  The performance of floor will, however, depend on whether the chemical and mechanical stress occurs simultaneously.  Variations in temperature would also affect the performance of the floor topping.

Maintenance - Very little maintenance is required for epoxy floor toppings.   However, the following precautions would prolong the service life of the topping.  (a)Usual house hold detergents, soap and warm water (up to 60° C) may be used for cleaning the floor.  Use of powerful oxidizing agents should be avoided. (b)The resin flooring tends to develop cracks when subjected to quick thermal cycles.  Hence frequent use of alternate cold and hot water hosing should be avoided. (c)  Dragging of heavy.

14.37.6. SPECIFICATIONS FOR CHEMICAL RESISTANT MORTARS

14.37.6.1. There are three types of chemical resistant mortars for different end uses, covered by the following Indian Standards:

(a)Use of Silicate Type by IS: 4441-1980. (b)Use of Sulphur Type by IS: 4442-1980, and (c) Use of Resin Type by IS: 4443-1980.

14.37.6.2. A mortar suitable for a particular environment is unsuitable for another.

a) Chemically setting silicate type of mortars are resistant to most acids and have been found to be satisfactory against nitric, chromic, sulphuric and hydrochloric acids.  They are used for acid proof bricks or tiles.  These mortars are not suitable for hydrofluoric and concentrated orthophosphoric acids.  They are also not resistant to alkalis, boiling water or steam and are likely deteriorate by continuous exposure to water or frequent washing with water.  In view of the fact that silicate types of mortars develop chemical resistance by physical bond formed by the chemical action of the acid with the mortar, the acid should have a pH value of 4 or less.  Manufacturer should be consulted regarding usage of these mortars. 

b) Sulphur mortars have good resistance against most of the acids except for concentrated oxidizing acids, but have very poor resistance to alkalis.  The Sulphur mortar shall always be used at less than 90°C.  Where conditions are questionable, specific recommendations of the manufacturer shall be obtained. 

c) Resin mortars have fairly good resistance to non-oxidizing mineral acids but have a poor resistance to oxidizing mineral acids.  They are fairly resistant to inorganic alkalis.  Manufacturer should be consulted on the usage of these mortars. 

14.37.6.3. Clauses 14.37.7, 14.37.8 and 14.37.9 would over the use of these mortars, namely, silicate type, resin type and Sulphur type.

14.37.7. SPECIFICATIONS FOR SILICATE TYPE CHEMICAL RESISTANT MORTARS

14.37.7.1. Material - Silicate type mortar shall conform to IS: 4832 (Part I)-1969.

14.37.7.2. Mortar - The chemically setting silicate type chemical resistant mortar is an intimate mixture of chemically inert solid filler, a setting agent usually contained in the filler and a liquid silicate binder.  When the filler and binder are mixed at ordinary temperatures, a trowel able mortar is formed, which subsequently hardens by the chemical reaction between setting agent and the liquid silicate binder. 

14.37.7.3. Storage - The filler shall be protected from water during storage.  The filler shall be kept in the containers if it cannot be protected otherwise.  The liquid binder shall be protected from freezing during storage until used.  Under unavoidable circumstances liquid binder that has frozen may be used, provided the liquid binder is thawed and thoroughly re-mixed before use and it can be restored to its original consistency. 

14.37.7.4. Mixing - Unless otherwise specified by the manufacturer, two to three parts by weight of filler to one part by weight may be used.  The optimum proportions might vary slightly due to climatic conditions, but it is important to have a mortar that is fluid enough to be workable and sufficiently stiff for the masonry unit to retain its position without slipping or sliding or without the mortar being exuded from the joint after the masonry unit has been placed in position. 

  1. Weigh the filler and binder in separate containers according to the recommended proportion.
  2. Add approximately three-fourths of the filler to the liquid binder in a clean container and mix with a trowel until all the filler has gone into paste.  Add the remaining filler to the paste and continue mixing until the mortar is uniform. In any batch only that quantity of mortar that could be used before it starts setting shalki be mixed.
  3. Mortar that has begun to set shall not be tempered by adding liquid binder or water but shall be discarded before preparing fresh batches. 
  4. Portland cement or water shall not be added to the silicate type of mortar.  Care shall be taken that the mortar does not come into contact with cement concrete surface. 
  5. Special precautions shall be taken when silicate mortars are exposed to temperatures below 10° C or above 27° C during mixing, application or setting. 

14.37.7.5. Application

a)  Surface preparation – The surface on which bricks to IS: 4860-1968 or tiles to IS: 4457-1982 are to be laid shall be free from dirt and dampness and shall be properly cured and dried.

b)  Application of membrane – A coat of bitumen primer conforming to IS: 3384-1986 be applied, and then covered with a coat of bitumen conforming to IS: 1580-1991.  If the bedding material is epoxy or polyester resin, the tiles or bricks may be laid directly on the surface without application of bitumen primer.  In case of furane, cashewnut shell liquid and phenolic types resins, a coat of bitumen primer conforming to IS: 3384-1986 shall be subject to service conditions.  Other membranes such as lead, polyisobutane and fibre reinforced plastics may also be used. 

c)  Mortar application with the same bedding and jointing materials

1)  For floors – Spread the silicate type of mortar 6 to 8 mm thick on the back of the tile or brick.  Smear two adjacent sides of the unit with 4 to 6 mm thick mortar.  Press the unit into the bed and push the unit until the joint in each case is 2 to 3 mm thick.  Trim off excess mortar and allow it to harden fully.  Cure the joints as given in 14.37.8.6 (b).

2)  For walls – Spread the silicate mortar 6 to 8 mm thick on the back of the unit.  Smear the two adjacent sides of the unit with 4 to 6 mm mortar.  Press the unit against the wall until joint in each case is 2 to 3 mm thick.  Trim off excess mortar.  While carrying out the jointing allow sufficient time to avoid the joints at bottom getting disturbed and sliding of the unit.  Only one course of unit shall be laid during the initial setting.  Cure joints as given in 14.37.8.6 (b).

d)  Mortar application with different bedding and jointing materials – when the job has to come into contact with water weaker acid solutions and alkalis, silicate type of mortar may be used for bedding and resin type of mortar for jointing.  The job shall be carried out with only class I bricks, if used. 

1)  On floors – Spread on two adjacent sides of the tile or brick the silicate type of mortar 6 to 8 mm thick.  Press the unit on the bed until the joint in each case is not more than 6 mm.  Before the silicate mortar sets completely, remove the mortar in the joints to a depth of 20 mm.  Cure the joints as in 14.37.8.6 (b) and fill the joints full with jointing mortar taking care to full up the entire length of the joint.  Trim off the excess mortar and make the joints smooth and plane. 

2)  On walls – Spread on to the back and two adjacent sides of the unit the silicate type of mortar 6 to 8 mm thick.  Press the unit against the wall until the joint in each case is not more than 6 mm.  Only one course of the unit shall be laid during the initial setting time to avoid the joints at the bottom getting disturbed and sliding of the unit.  Cure the joints as given in 14.37.8. 6 (b) and fill the joints full with the jointing mortar to fill up the entire length of the joint.  If Sulphur mortar is used, seal the vertical and horizontal joint with a strip of gummed paper 25 mm wide to prevent the flow of Sulphur mortar from the joints.  Strip off the gummed paper after the mortar has set.  Trim off excess mortar to make the joints smooth and plane. 

14.37.7.6. Acid–curing

a) Acid-curing shall be carried out as per manufacturer’s instructions, using safety precautions normally used when handling such acids.  The operators shall be provided with suitable aprons, gloves, boots, etc.  The mortar joints shall be cured with 20 to 25 percent hydrochloric acid or with 30 to 40 percent sulphuric acid no sooner than 2 days and not later than 6 days after the masonry units have been bonded with the mortar.  The curing time shall be at least 60 min.  If the constructed unit is designed to contain a liquid, it may be  filled with acid of the type and concentration stated above, with the time interval stated, in lieu of washing the joints.  In no case shall the acid solution be made by partially filling the tank with water and then adding acid.  When sulphuric acid is used for curing, the solution shall not be prepared inside the unit. 

Note: (a) 20 percent hydrochloric acid can be made by mixing 3 parts by volume of commercial 20° Baume hydrochloric acid with 2 parts by volume of water.  Forty percent sulphuric acid can be made by mixing 2 parts by volume of commercial 66° Baume sulphuric acid with 5 parts by volume of water. 

(b) When the bedding material is silicate type mortar and the jointing material is epoxy resin type or polyster type or Sulphur type mortar, no acid curing is required.  When the bedding material is silicate type and the jointing material is phenolic resin type or furane type or cashew nut shell liquid type, the joints shall be cured as in 14.37.8.6 (a) before applying the jointing material. 

14.37.7.7. Chemical resistance of silicate type mortars - A general guide for chemical resistance of silicate type of mortars to various substances is given in Table 11.  The ratings are for immersion service at ambient temperature and may be usually upgraded for spillage only.  The chemical resistance of silicate type of mortars shall be determined by IS: 4456 (Part I)-1967. 

14.37.8. SPECIFICATIONS FOR RESIN TYPE CHEMICAL RESISTANT MORTAR

14.37.8.1. Material - The resin shall conform to the requirements laid down in IS: 4832 (Part 2)-1969.

14.37.8.2. Storage - The resin shall be stored in a clean dry place away from open flame and under roof with containers tightly closed.  The resins could be generally stored without deterioration at 27 ±2° C for periods not exceeding the values given below.  The filler or resin that has become wet shall not be used. 

Type of resin

Storage period in months

i)

Cashewnut shell liquid

9

ii)

Epoxy

12

iii)

Furane

12

iv)

Phenolic

3

v)

Polyester

3

14.37.8.3. Safety precautions -  Both the liquid and powder ingredients may contain materials that may affect the skin.  Therefore either gloves or barrier cream shall be used while handling these materials.

Vapour is present in most of the resin mortars and same produce gases during curing.  Adequate ventilation shall be provided in the mixing and working areas.  Under confined areas like vessel lining, etc, forced air draught may be used. 

Resin mortars, labeled as inflammable by manufacturers shall be used with adequate safety precautions against fire.  Solvents used for cleaning tools are generally inflammable.  Fires shall be kept away from the area in which such solvents are used and ‘No Smoking’ sign shall be posted in these areas. 

14.37.8.4. Mixing

  1. For hand mixing required quantity of liquid resin shall be poured into a basin. The powder shall then be added gradually and the mixture shall be well stirred working out all lumps and air bubbles.  The mortar shall be mixed to the proportion as specified by the manufacturer for a particular type of job.  A stainless steel spatula may be used for mixing purposes. 
  2. Only such quantity of mortar that could be consumed within 15 to 20 min shall be prepared unless otherwise recommended by the manufacturer.

14.37.8.5. Handling

  1. Resin mortars cure slowly at low temperatures.  If the work is to be carried out at temperature below 15° C, to masonry units should be warmed and the area of work shall be enclosed and heated to above 15° C by using infrared lamp, to obtain proper curing.
  2. Mixed mortar, that has become unworkable shall not be re-tempered with liquid resin, but shall be discarded.

14.37.8.6. Application

a)  Surface preparation – The surface on which bricks conforming to IS: 4860-1968 or tiles conforming to IS: 4457-1982 is to be laid shall be free from dirt and dampness and shall be properly cured and dried. 

b)  Application of membrane – A coat of bitumen primer conforming to IS: 3384-1986 shall be applied on the prepared surface.  A uniform coat of bitumen conforming to IS: 1580-1991 shall then be applied.  If the bedding material is epoxy or polyester resin, the tiles or bricks can be laid directly on to the surfaces without application of bitumen primer.  In case of furane, cashew nut shell liquid and phenolic resin, a coat of bitumen primer shall be used subject to service conditions.  Other membranes, such as, rubber, lead, polyisobutane and fibre-reinforced plastics can be used in place of bitumen primer.  

c)  Mortar application with the same bedding and jointing materials

1)  On floors – Spread the resin type of mortar 6 to 8 mm thick on the back of the unit.  Smear two adjacent sides of the unit with 4 to 6 mm thick mortar.  Press the unit into the bed and push against

the floor and the unit until the joint in each case is 2 to 3 mm thick.  Trim off excess mortar and allow it to harden fully.  Cure with acid as given in 14.37.9.7, except for epoxy and polyester resins. 

2)  On walls – Spread the resin type mortar 6 to 8 mm thick on the back of the unit.  Smear two adjacent sides of the unit with 4 to 6 mm mortar.  Press the unit against the wall until the joint in each case is 22 to 3 mm thick.  Trim off excess mortar and allow it to harden fully.  While carrying out the jointing allow sufficient time to avoid the joints at the bottom getting disturbed and sliding of the unit.  Only one course of tile or brick shall be laid during the initial setting.  Cure with acid as in 14.37.9.7 except for epoxy and polyester resin.  

d)  Mortar application with different bedding and jointing materials

1)  On floors – Spread on to the back and two adjacent sides of the unit the silicate type mortar 6 to 8 mm thick.  Press the unit on the bed until the joint in each case is 3 to 6 mm thick.  Before the silicate mortar sets completely, the jointing material is removed to a depth of 20 mm.  The material thus removed may be used for bedding providing it is trowelable and has not hardened.  After the bedding mortar is properly set cure the joints as given in 14.37.9.7 and fill the joints full with resin type mortar taking special care to fill up the entire length of the joint.  Trim off excess mortar to make the joints smooth and plane. 

2)  On walls – Spread to the back and two adjacent sides of the tile or brick the silicate type mortar 6 to 8 mm thick, press the unit against the wall until the joint in each case is 3 to 6 mm thick.  Only one course of the unit shall be laid during the initial setting time to avoid the joints at the bottom getting disturbed and sliding of the unit.  Before the silicate mortar sets completely, the jointing material shall be removed to a depth of 20 mm which may be used for bedding provided it is trowelable and has not hardened.  Cure the joints as given in 14.37.9.7 and fill the joints full with resin type of mortar taking care to fill the entire length for the joint.  Trim off excess mortar to make the joints smooth and plane. 

14.37.8.7. Acid-curing - Except for epoxy and polyester resins, cure the joints for a minimum period for 72 h with 20 to 25 percent hydrochloric acid or with 30 to 40 percent sulphuric acid before applying the resin type of mortars.  After acid-curing, wash the free acid in the joints with clean water and allow sufficient time for thorough drying.  Resin mortars shall then be filled into the joints. 

Resin mortars are normally self curing and do not generally require an auxiliary curing.  They should not be put to use before 48 h in the case of furane, epoxy and polyester resin type mortars.  They may be put to use after 48 h provided the setting temperature is at least 20° C.  in the case of phenolic and cashew nut shell liquid resin and for lower temperatures the period of curing shall be extended as recommended by the manufacturer.  Without any heat treatment phenolic resin and the cashew nut shell liquid resin shall not be put to use for 7 to 28 days respectively.  With the treatment phenolic resin and the cashew nut shell liquid resin may be put to use after 2 to 6 days respectively.  The construction shall be protected from weather and water and from accidental mechanical damage until the mortar is cured.  Heat treatment may be given with infrared lamp. 

14.37.8.8. Chemical resistance of resin type mortars - As a general guide the chemical resistance of resin type mortars to various substances is as given in Table 12.  The ratings are for immersion service at ambient temperature and may be upgraded for spillage only.  Manufacturer’s instructions shall generally be followed.  IS: 4456 (Part 1)-1967 may be used for testing. 

14.37.9. SPECIFICATIONS FOR SULPHUR TYPE CHEMICAL RESISTANT MORTAR

14.37.9.1. Material - Sulphur type mortar shall conform to IS: 4832 (Part 3)-1968.

14.37.9.2. Storage - Sulphur mortar shall be kept in a dry place prior to use.  The mortar shall not deteriorate during storage.

14.37.9.3. Safety precautions

a) Sulphur mortar is melted and poured between bricks or tiles.  If overheated, it ignites and burns with a low blue flame.  When the blue flame is observed, heating shall be stopped and the vessel shall

be covered with a tight fitting lid or wet gunny bags until the fire is extinguished.  When applying Sulphur mortar in a confined space, each pail or molten material shall be checked to ensure that the mortar is not burning.  The blue flame shall be checked in a dark place. 

b) All Sulphur coming into contact with molten Sulphur mortar shall be kept dry.  Adequate safety precautions shall be taken during melting and pouring of Sulphur mortars.  The operators shall be provided with leather aprons, asbestos gloves, asbestos boots, goggles and masks.  The areas where melting and pouring is carried out shall be checked for flammable or explosive a gases and a flame permit shall be issued before the fires are lit or molten Sulphur mortar is carried into the area.  Soda acid type fire extinguisher and wet cloth shall be made available for extinguishing fire or preventing its spread.  Water shall be kept away from molten Sulphur mortar in order to avoid foaming.  Adequate ventilation should be provided wherever Sulphur mortars are used.

Table 12 - Chemical resistance of resin type mortars

Sl

No

Substance

Epoxy

Polyester

Phenolic

Furnae

Cashew

Nut Nutshell

Liquid

 

Acids

 

 

 

 

 

i

Acetic acid 10%

R

R

R

R

R

ii

Chromic acid 10%

N

R

L

N

L

iii

Hydrochloric acid (conc)

R

R

R

R

R

iv

Hydrofluoric acid (see Note)

N

N

R

R

R

v

Lactic acid 2%

R

R

R

R

R

vi

Nitric acid (10%)

L

N

L

N

L

Vii

Nitric acid (conc)

N

N

N

N

N

Viii

Phosphoric acid 10%

R

R

R

R

R

ix

Sulphuric acid 10%

R

R

R

R

R

x

Sulphuric acid 40%

R

R

R

R

R

xi

Sulphuric acid (conc)

N

N

L

N

N

 

Alkalis

 

 

 

 

 

i

Ammonia 0.880

R

N

L

R

R

ii

Sodium hydroxide 40%

R

N

L

R

L

ii)

Sodium carbonate

R

L

R

R

R

iv

Calcium hydroxide

R

N

R

R

R

 

Salt solutions

 

 

 

 

 

i

Salt solution (acidic)

R

R

R

R

R

ii

Salt solution (alkaline)

R

L

R

R

R

 

Solvents

 

 

 

 

 

i

Aliphatic hydrocarbons

R

R

R

R

N

ii

Aromatic hydrocarbons

L

N

R

R

N

iii

Alcohols

R

R

R

R

R

iv

Ketones

L

N

L

R

R

v

Chlorinated hydrocarbons

L

L

R

R

N

 

Wet gases (oxidizing)

N

N

N

N

N

 

Wet gases (reducing)

R

R

R

R

R

 

Mineral oils

R

R

R

R

L

 

Vegetable oils and fats

R

R

R

R

L

R = Generally recommended.  L = Limited use.  N = Not recommended.

Note: Carbon and graphite fillers should be used for hydrofluoric acid service.

14.37.9.4. Melting and pouring

  1. The mortar shall be melted in a clean vessel made of cast iron, or steel, or aluminium.  It shall be filled with dry Sulphur mortar to not more than one half and heated slowly until the mortar has melted to a black, smooth liquid with a mirror bright surface and the liquid is almost as free flowing as water, while stirring frequently with a steel ladle.  The Sulphur mortar must be dry at the time of use to avoid foaming.  The mortar shall be heated to a temperature of about 135° C.  Below 130° C some of the liquid will congeal over the top or around the sides of the vessel.  If the mortar is heated much above 135° C, the viscosity increases until the mortar thickness and loses its mirror like appearances.
  2. If the mortar thickens on overheating, it should be allowed to cool and stirred until thin; then more cold mortar may be added, if necessary, overheating for long periods may permanently damage the mortar.  Care shall be taken that water or damp mortars do not get into the heating vessel so as to avoid foaming. 
  3. The molten Sulphur mortar shall be taken in galvanized bucket.  The nose of the bucket shall be directed towards the joint and the hot and viscous mortar is poured slowly into the joint without air entrapment.  Any entrapped air should be removed while the mortar is hot by poking with a thin mild steel rod. 

14.37.9.5. Application

a)  Surface preparation – The surface to receive the acid resistant bricks and tiles shall be free from dirt and dampness and shall be cured and dried. 

b)  Mortar application with same bedding and jointing materials

1)  On floors – Spacer chips with a surface area of about 1 cm2 and 6 mm thick and made of Sulphur mortar conforming to IS: 4832 (Part 3)-1968 shall be made available.  The chemical resistant brick or tile shall be placed on spacer chips, 3 chips being used under each tile.  Between the floor and tile or brick 6 mm space shall be provided.  The molten Sulphur mortar shall be poured in a maximum of two operations in spaces between floor and the units avoiding air pockets till it completely fills the joints.  Trim off excess mortar to make the joints smooth and plane using a hot trowel. 

2)  On walls – The chemically resistant unit shall be placed 6 mm away from the wall and the adjacent unit using spacer chips with a surface area of 1 cm2 and 6 mm thick and made out of Sulphur mortar.  The vertical and horizontal joints are sealed with gummed strip of paper 25 mm wide to prevent molten Sulphur mortar flowing from the joints.  The mortar shall be filled leaving a gap of 25 mm from the top and avoid air entrapment.  A further course of the unit shall be laid in the same way immediately thereafter.  The gummed paper can be stripped off as soon as the Sulphur mortar has hardened. 

c)  Mortar application with different bedding and jointing materials

1)  On floors – Spread on to the back and two adjacent sides of the unit the silicate type of mortar 6 to 8 mm thick.  Press the unit on the bed and push against the floor and the unit until the joint is not more than 6 mm thick.  Before the silicate mortar sets completely, the jointing material is removed to a depth of 20 mm.  The material thus removed may be used for bedding provided it is trowelable and has not hardened.  Cure the joints with acid for a minimum period of 72 h and dry.  If the bedding material is silicate mortar, the laying and curing shall be done as per 14.37.9.6.  Fill up the joint completely to its entire length with Sulphur mortar.  Trim off excess mortar to make the joints smooth and plane with a hot trowel. 

2)  On walls – Spread on the back and two adjacent sides of the unit, silicate mortar 6 to 8 mm thick.  Press the unit against the wall and with the adjacent unit until the joint in each case is not more than 6 mm thick. Only one course of the unit be laid during initial setting time to avoid the joints at the bottom getting disturbed and the unit getting slided. Before the mortar sets completely remove the jointing material to a depth of 20 mm.  The material thus removed may be used for bedding provided it is trowelable and has not hardened.  After the bedding mortar has set, cure the joints with resin for a minimum period of 72 h and dry.  If the bedding material is silicate type the laying and curing shall be as per 9.6.  Seal the vertical and horizontal joints with a strip of gummed paper 25 mm wide to prevent the flow of Sulphur mortar from the joints.  Fill up the joints completely with molten Sulphur mortar avoiding air entrapment.  Strip off the gummed paper after the mortar has hardened.  Trim off excess mortar with a hot trowel to make the joints smooth and plane. 

d)  Protecting the units from mortar – Various methods are available for masking the masonry units to prevent Sulphur mortar from adhering to them.  Paraffin wax, paper, etc, may be used to cover the masonry units.  The paraffin wax or paper shall be removed after use. 

e)  Floors laid with Sulphur mortar shall not be put into service before 8 hours of laying. 

14.37.9.6. Chemical resistance of Sulphur type mortars

A general guide for chemical resistance of Sulphur type mortars is given in Table below.  The ratings are for immersion service at ambient temperature and may usually be upgraded for spillage.  The chemical resistance of Sulphur type mortar shall be determined in accordance with the method described in IS: 4456 (Part 2)-1967.

Chemical resistance of Sulphur type mortar

Sl.No

Substance

Chemical resistance

 

Acids

 

i

Hydrochloric acid (concentrated)

R

ii

Sulphuric acid (70%)

R

iii

Sulphuric acid (above 70%)

L

iv

Nitric acid (40%)

R

v

Nitric acid (above 40%)

N

vi

Organic acid

L

vii

Hydrofluoric acid (40%) (see Note)

R

 

Alkalis

 

i

Sodium hydroxide (1%)

R

ii

Sodium hydroxide (above 1%)

N

iii

Sodium carbonate (concentrated)

R

iv

Salt solutions (acidic)

R

v

Salt solutions (alkaline)

L

 

Solvents

 

i

Aliphatic hydrocarbons

L

ii

Aromatic hydrocarbons

L

iii

Alcohols

R

iv

Ketones

L

v

Chlorinated hydrocarbons

L

 

Fats and Oils

L

R = Generally recommended, L = Limited use, N = Not recommended.

Note: Graphic and carbon filler should be used for hydrofluoric acid service.

14.37.10. SPECIFICATIONS FOR PARQUET FLOORING

14.37.10.1. General – Parquet flooring is covered by the following Indian Standards:

IS: 5389-1969             Hardwood parquet and wood block floors

IS: 9472-1980             Mosaic parquet flooring

a) Parquet flooring are used in auditorium, squash courts, skating rinks, dancing halls, etc.

b) Mosaic parquet floors consists of many small pieces of (slats) which are liable to compensate very successfully the inevitable warping of wood due to variations in humidity without resulting in gaps so

objectionable in strip parquet; at the same time gluing also remains perfect.  New patterns may be provided with mosaic parquet which are not possible with conventional strip parquet. 

14.37.10.2. Materials

a)The species of timber for hardwood parquet and wood block floors are given in Annexure 14-A.3 along with the indentation index, compared to teak as 100.   The sawn timber shall be non-refractory and the thickness of floor blocks and parquets shall be 25 to 40 mm.  Nails used shall be diamond pointed (see IS: 723-1972).

b) The percentage indentation for hardness shall be not less than 55 so as to withstand constant wear and tear. 

c) Timber shall be seasoned as per IS: 1141-1993 and thereafter treated with preservatives as per IS: 401-1982.  In case water soluble preservatives are used, timber shall be seasoned a second time after preservation.  Termite control and damp proofing shall be as per specifications.

14.37.10.3. Classes of mosaic parquet flooring - They shall be of two classes.

Class I: Slats may be quarter, half quarter or rectangular sawn provided that the number of tangential sawn slats does not exceed 30 per cent of the slats in each panel. 

Face shall be free from sound knots exceeding 2 mm in diameter and loose knots exceeding 1 mm in diameter.  Knots up to 5 mm diameter may be permitted in the back. 

Class II: Only one of the defects mentioned from i) to v) below, apart from sound knot is permitted on the face of a slat; back may exhibit knots and other defects of a larger size. 

(i) Sound knots, of a colour very nearly approaching that of adjoining wood; ½ width of slat. 

(ii) Loose knots, of a colour contrasting with that of adjoining 1/5 of width of slat.

(iii) Cross gain, (iv) Waned wood; maximum 1/25 width of slat, and (v) Stains.

14.37.10.4. Parquet floor patterns - They shall be as given in Figure 15 and Figure 16.

Fig. 15 Different designs of panel for parquet flooring

14.37.10.5. Wood Block flooring Patterns (Types of blocks and wood block floor)

They shall be as given in Fig.17, Fig. 18 and Fig. 19.

14.37.10.6. Mosaic parquet panel - It shall be as In Fig. 20.

14.37.10.7. Dimensions - Mosaic parquet floors shall be of 6, 8 and 10 mm thickness; 6 mm thickness is not suitable for softwood and softer grades of hardwood; width shall be 18 to 25 mm.  Length shall be 100 to 165 mm.

Fig 16 Parquet floor laid in panels

14.37.10.8. Fabrication and laying

a) Parquet floor shall be consisting of the following:

1)  Sub floor – The sub-floor shall be planed of timber boarded floor 50 to 75 mm thick (see IS: 3670- 1989 or Part 5).  The sub-floor may also be of cement concrete. 

Fig. 17 Patterns of wood block flooring

Fig. 18 Different types of wood blocks

1) Panels – These shall be generally 30 to 35 cm2.

2) Square edged hardwood battens – These shall be generally 15 to 50 cm in length, 5 to 10 cm in width and 5 to 10 mm in thickness.

Fig 19 Wood floor block

Fig. 20 Typical illustration of Mosaic parquet panel

b) The laying of parquet floor shall be done as below:

1) Border shall be fitted first to a width of 60 cm and the area is laid and fitted dry. 

2) Every individual piece of parquet is taken up in turn and placed in position with mastic;

3) Before the mastic hardens, nails are driven in;

4) The floor is scraped or planed to an even surface and sand papered; and

5) The nail holes punched in area filled with putty and the floor is polished with the use of power-driven machines.

c) The wood block floors shall be in herring-bone or basket patterns.  The blocks shall of the types given below:

  1. Simple square end block with dove-detailed grooves on the bottom,
  2. Tongued and grooved,
  3. Tongues on the ends, and
  4. Dovetailed groove on the bottom and with a narrow groove. 

d) Laying of woodblock floor shall be done as below :

1) Sub-floor shall consist of cement concrete flooring of 5 to 7.5 cm thick, finished smooth. 

2) The wood blocks, sizes from 25cm X 7.5 cm to 30 cm X 7.5 cm, shall be dipped in liquid mastic composition adhering to cement. 

3) The centre of the floor shall be laid first with the border cut and fitted to it.  Generally two rows of wood blocks shall be laid longitudinally to serve as border.  The floor is scraped and planed to an even surface and sand papered.

4) The pores in the floor shall be sealed by an appropriate floor seal. 

e) Mosaic parquet floors shall be laid as below:

1) Adhesives for gluing parquet shall be of solvent and dispersion type, such as, epoxy resin or phenolic resin (resorcinol formaldehyde), or urea formaldehyde synthetic adhesives.  All parquet adhesives are diluted (mixed) with various mineral components; they are applied by means of a toothed steel trowel as thin as possible.  Only a limited area shall be primed in order to prevent setting. 

2) Mosaic parquet are laid over battened floors which are even.  The mosaic parquet shall be laid diagonally to the direction of battens.  In old and uneven battened floors, plywood or other boards may be inserted between the floor and mosaic parquet.  The boards may be glued or nailed to the floor and the old batten floor be made even. 

3) Adhesive shall be applied on the prepared and dry surface and the back of parquet.  Apply pressure on the parquet panel to get a good bond.  Joints shall be very thin and fine.

4) Mosaic parquet floors shall be finished as in section on finishes of wood work. 

14.38. SPECIFICATIONS FOR TIMBER FLOORS

14.38.1. General - Timber floors are provided in auditoria, gymnasia, dancing halls, squash courts, public balconies, galleries, skating rinks, etc, for noise retardant floor finish and in hilly areas as thermal insulating floor finish.  These floors may also be used in timber framed construction to serve as structural floors.

14.38.2. Materials - The species of timber recommended for floor board shall be as given in Annex B   with their percentage of indentation for hardness, taking teak as 100.

a) Species of timber selected for girders, binders and projecting joists shall be as given below

1) For spans of 12 m and greater, all the species of Group ‘Super’ specified in IS: 3629-1986.

2) For spans greater than 6 m but less than 12 m, all the species of Group ‘Standard’ specified in IS: 3629 -1986.

3) For spans up to and including 6 m, all the species of Group ‘Ordinary’ specified in IS: 3629 - 1986.

b)  Timber selected for construction of floor boards and supporting members shall conform to the following;

1) The species should be non-refractory; 2) The thickness of boards shall be from 25 to 40 mm.

3) For joists, binders and girders the modulus of elasticity should be not less than 5.625 N / mm2 and the extreme fibre stress should be not less than 8.5 N / mm2.

Nails conform to IS: 723-1972 and diamond pointed.

All timber shall be seasoned as per IS: 1141-1993 and preserved as per IS: 401-1982. If water preservatives are used, it shall be seasoned a second time.  Proper anti-termite measures shall be adopted for use in buildings.  Damp-proofing, where necessary, shall be done described in Section 10 of KBS.

14.38.3. Types of timber floors - Timber floors are generally of the following types

  1. Single joisted floors having bridge joist only ;
  2. Double joisted floors having bridge joists supported on binders ;
  3. Triple joisted floors having bridging joists supported on binders and framed into girders ;
  4. Solid timber floors/wood block floor ; and
  5. Purpose made floor / parquet floors, etc.

14.38.4. Construction 

14.38.4.1. Single joisted timber floor - This type is constructed on ground floor, generally in theatres where dance and drama performances are regularly held.  Also they are suited for buildings in hilly regions and damp areas. The construction sequence is as below

a) Clear the site of vegetation, etc.

b) Honey-combed dwarf walls are built, preferably half brick thick at intervals of 2 m to a suitable height.

c) In case of basement floors, particularly, for theatres, the space between the dwarf walls may be filled with dry sand up to DPC level as shown in Fig. 21

d) Over the DPC on dwarf walls longitudinally wooden members, or wall plates, are solidly bedded level by means of suitable lime or cement mortar.

e) The timber floor joists (bridging joists) are mailed to these wall places see Fig.22

f) Proper ventilation should be ensured to prevent dry rot of timber.

g) There should be a gap between the underside of every joists/girder of the ground floor and top surface of sand filling or site concrete.

h) Wall plates and ends of joists should not be built into the side walls.  Spacing of joists may be between 300 to 450 mm.

i) On properly fixed joists, wooden boards 25-30 mm thick, 100-150 mm wide and 3 m long generally widened by tongued and grooved joints shall be laid and fixed by screw/nails.

j) The surface of the boards are leveled and rubbed smooth.

Timber floors for upper floors. The details are as in Fig.  22

14.38.4.2. Double joisted timber floor - These are used for longer spans between 3.5 m and 5 m.  To make it more sound proof the construction procedure is as follows.

a) The bridging joists, instead of spanning from wall to wall, are supported by larger horizontal members (binders) at suitable intervals, between 2 m to 5 m in the shorter direction of the room.

b) Floor boards are supported on bridging joists.

c) The binders shall not be placed over door window openings unless designed as lintels.  Ends of binders should not touch masonry.

d) Ceilings may be fixed to the bottom of the binders.

14.38.4.3. Triple joisted timber floor - The details are as in BIS

14.38.4.4. Solid timber floors - The details are as in Fig. 23.

14.38.4.5. Purpose–made floors - These are not generally made solid; they are primarily hollow floors.  They are named according to purpose they serve, namely, Skating-rink floor, Badminton floor, Squash floor, etc.  Some details are as in Fig. 24.

14.38.5. Timber floor boards - The timber floor boards, 25 to 30 mm thick, 100 to 150 mm wide and 2 to 3 m long are joined by widening joints listed in order of efficiency as given below (see Fig. 25)

Fig 21 Basement timber floor

Fig 22 Single joisted upper floor

Fig 23 Room showing sub-flooring of cement concrete and wooden fillets

Fig 24 Typical detail of fixing of floor joist and timber floor

Fig 25 Different types of joints in timber flooring boards

14.39. SPECIFICATIONS FOR LYING OF FLEXIBLE PVC SHEET AND THE FLOORING

14.39.1. PVC flooring material manufactured in different patterns to match and suit any decorating scheme is normally used for covering floors from decorative point of view in residential and office buildings and also in railway coaches.  The material gives a resilient and non-porous surface which can be easily cleaned with a wet cloth as dust and grime do not penetrate the surface.  Since a burning cigarette will damage the neat surface of the PVC sheet, special care should be taken to prevent burning cigarette stumps to come in contact with the PVC flooring material.

The performance of the PVC flooring depends very much on the preparatory treatment given to the sub-floor, the selection of an appropriate adhesive for fixing, the care being taken in laying the flooring material on the sub-floor and the maintenance of the finished floor.  Special care should be taken in preparing the sub-floor and making the base permanently dry so that the PVC flooring after laid will not be affected by absorption of moisture by the sub-floor.  Hot sealing of joints between adjacent PVC flooring to prevent creeping of water through the joints is under study as the method is likely to increase the life of the floor.

For the purpose of this specification, the following definitions shall apply.

Flooring – The resilient PVC flexible sheet or tile or PVC (vinyl) asbestos tile flooring material.

Screed topping – A bed of cement mortar (1 cement: 3 sand) applied to a sub-floor and brought to a defined level.

Sub-floor – The surface on which the flooring is to be laid.

Underlay – A layer of sheet material or in situ filling on the sub-floor or the screed topping to provide a smooth level surface to receive the flooring.  Underlay may be in the form of sheet underlay or trowelled underlay.

Material: Flooring – The flooring shall comply with the requirements specified in IS: 3461-1966 and IS: 3462-1966.The thickness of the flooring shall depend on the service conditions.

Underlay - Underlay shall be compatible with the flooring and adhesive to be used.  Underlay for use on concrete sub-floor shall be the screed topping. Underlay for use on uneven and rough wood sub-floor shall be 3 mm thick BWR grade plywood conforming to IS: 303-1960.

Adhesives – Rubber based adhesives are suitable for fixing PVC flooring over concrete, wooden and metal sub-floors.  PVA based adhesives may be used for concrete and wooden sub-floors.  PVA based adhesives are not suitable for metallic surfaces and also for locations where there is constant spillage of water.

Necessary information - For efficient planning and execution of the work, the following points shall be taken into account:

 Area of floor;

(a)Type of sub-floor and underlay; (b)Type and thickness of screened bed, if any; (c)Curing and drying time for concrete bed and screed;(d)Damp-proofing treatment provided; (e)Evenness of the finished floor;(f)Type, quality and thickness of flooring;(g)Services passing through flooring; (h)Treatment of skirting;(i)Treatment of junction with adjacent flooring;(j)Type of ventilation provided to wood sub-floor;(k)Any dressing or polishing required; and (l)Protection of completed flooring.

Preparation of sub-floors

14.39.1.1. The PVC flooring gives good service when laid on a firm base.  Evaporation of moisture from the sub-floor cannot take place once the PVC flooring is laid.  Therefore, it is important that sub-floor and underlay should be thoroughly dry before laying the PVC flooring.  An irregular sub-floor surface creates poor adhesion between the sub-floor and the PVC flooring; therefore, the sub-floor surface should be leveled.  Recommended treatments for different sub-floors shall be as specified.

14.39.1.2. Timber

In the case of new construction, seasoned and treated timber shall be used and shall preferably be of tongued and grooved boarding.  Boards should be narrow and of equal width.  Boards of very unequal width have various degrees of shrinkage.  Before fixing the PVC flooring, all nail heads on the timber sub-floor shall be punched down, irregularities planed off and holes filled with suitable fillers.  High spots on the timber sub-floor produce spots of rapid wear in the flooring.  In case of suspended timber floor which is properly designed and is well ventilated, covering the floor with PVC flooring does not result in the growth of fungus.  In the case of badly ventilated timber floor, any impervious covering like the PVC flooring reduces the already deficient ventilation and allows the moisture content of the timber to increase sufficiently to encourage fungal attack.  Because of the risk of fungal attack, wood blocks and boarded floor over concrete laid on the ground shall not be covered with PVC flooring unless an efficient damp-proof membrane in the concrete below the blocks has been provided.

In the case of an existing timber floor, covered with boarding when it is not possible to obtain an even surface or in cases of fungal attack, the use of diagonal boarding is recommended, after removing and replacing some of the badly affected boarding and filling in cracks with plastic wood or similar filler and after disinfecting the floor.  Alternatively, plywood topping in accordance with 3.2.1.2 on the existing boarding also gives an even surface.  It is important to see that floor is well ventilated.

14.39.1.3. Concrete

A concrete sub-floor on the ground intended for fixing PVC flooring shall contain an effective damp-proof course, shall be finished with a trowel and shall be left long enough for the concrete above the damp-proof course to dry out.  The damp-proofing treatment shall be given in accordance with the approved methods.  

The concrete sub-floor shall be laid in two layers.  The top of the lower layer of concrete shall be painted with two coats of bitumen, conforming to IS: 1580-1969 applied at the rate of 1.5 KG/M2.  The surface of the lower layer shall be finished smooth while laying the concrete so that bitumen can be applied uniformly.  The bitumen shall be applied after the concrete has set and is sufficiently hard. 

Bitumen felt conforming to IS: 1322-1967 shall be sandwiched in the sub-floor concrete laid in two layers.  The surface of the lower layer shall be finished smooth while laying the concrete so as to provide an even surface and thus prevent damage to the surface of the bitumen felt water proofing membrane.

Where it is expected that the dampness may find its way from the surrounding walls, the same shall also be effectively damp-proofed up to at least 150 mm above the level of the sub-floor and the damp-proof treatment below the floor shall be extended over the walls.  The basement floor shall be damp-proofed according to the recommendations of IS: 1609-1966.

Before PVC flooring is laid, ample time shall be allowed for the water to dry completely from the concrete floor.  It is difficult to specify the period required as it depends on weather and on the quality and thickness of the concrete, but a period of at least 4 to 8 weeks shall be allowed for drying under normal conditions.  The time may be reduced if the building is well ventilated.

In new work, the finish required for laying PVC flooring shall be produced with a trowel on a screed applied to the sub-floor concrete.  The finish may, however, be produced on the sub-floor concrete itself by using a power-float.  With old concrete, the surface shall be scrapped free of all foreign material and swept clean.  The surface shall be kept wet for 24 hours by sprinkling water and then screed topping of 3 mm thickness shall be provided over the concrete.  If the existing concrete surface is even, the sub-floor shall be cleaned and made free of grease, oil, paint and other deleterious materials.  A separate layer of screed topping may not be necessary in this case.

14.39.1.4. Metal floors – Metal floors shall be made free from rust and scale by chipping and/or vigorous wire brushing and cleaning.  Metal floors shall be free from undulations due to welded joints.  The welded joints which may come in contact with the PVC flooring shall be ground smooth.  Paint and grease shall be removed by caustic soda washing followed by thorough rinsing with fresh water.  Suitable putty compatible with the adhesive shall be used for filling metal surfaces to obtain a smooth, uniform and free from indentations and protrusions.

14.39.2. Laying and fixing of PVC flooring - Prior to laying, the flooring shall be brought to the temperature of the area in which it is to be laid by stacking in a suitable manner within or near the laying area for a period of about 24 hours.

Where air-conditioning is installed, the flooring shall not be laid on the sub-floor until the conditioning units have been in operation for at least seven days.  During this period the temperature shall neither fall below 20oC nor exceed 30oC.  These conditions shall be maintained during laying and for 48 hours thereafter.

Before commencing the laying operations, the sub-floor shall be examined for evenness and dryness.  The sub-floor shall then be cleaned with a dry cloth.  The PVC flooring shall not be laid on a sub-floor unless the sub-floor is perfectly dry.  Methods of testing for dryness are given in 14.39.9. 

The layout of the PVC flooring on the sub-floor to be covered should be marked with guidelines.  The PVC flooring shall be first laid for trial without using the adhesive according to the required layout.

The adhesive shall be applied by using a notched trowel (see fig. Below) to the sub-floor and to the back side of the PVC sheet or tile flooring.  When set sufficiently for laying, the adhesive will be tacky to the touch, but will not mark the fingers.  In general, the adhesive will require about half an hour for setting, it should not be left after setting for too long a period as the adhesive properties will be lost owing to dust films and other causes. 

Care should be taken while laying the flooring under high humidity conditions so that condensation does not take place on the surface of the adhesive.  It is preferable to avoid laying under high humidity conditions.

The area of adhesive to be spread at one time on the sub-floor depends entirely upon local circumstances.  In case of a small room adhesive may be spread over the entire area but relatively small areas should be treated in a larger room.

When the adhesive is just tack free, the PVC flooring sheet shall be carefully taken and placed in position from one end onwards slowly so that the air will be completely squeezed out between the sheet and the background surface.  After laying the sheet in position, it shall be pressed with suitable roller to develop proper contact with the sub-floor.  The next sheet with its back side applied with the adhesive shall be laid edge to edge with the sheet already laid and fixed in exactly the same manner as the first sheet was fixed.  The sheets shall be laid edge to edge so that there is minimum gap between joints.

The alignment should be checked after laying of each row of sheet is completed.  If the alignment is not perfect, the sheets may be trimmed by using a straight edge.

The tiles shall be fixed in exactly the same manner as for the sheets.  It is preferable to start laying of the tiles from the centre of the area.  Care should be taken that the tiles are laid close to each other with minimum gap between joints.  The tiles should always be lowered in position and pressed firmly on to the adhesive.  Care should be taken not to slide them as this may result in adhesive being squeezed up between the joints.  PVC tiles after laying shall be rolled with a light wooden roller weighing about 5 kg to ensure full contact with the underlay.  Any undulations noticed on the PVC surface shall be rectified by removing and relaying the tiles after thorough cleaning of the underside of the affected tiles.  The adhesives applied earlier in such places shall be thoroughly removed by using proper solvents and the surface shall be cleaned to remove the traces of solvents used.  Work should be constantly checked against guidelines in order to ensure that all the four edges of adjacent tiles meet accurately. 

Any adhesive which may squeeze up between sheets or tiles should be wiped off immediately with a wet cloth before the adhesive hardens.  If, by chance, adhesive dries up and hardens on the surface of the sheet or tile, it should be removed with a suitable solvent.  A solution of one part of commercial butyl acetate and three parts of turpentine oil is a suitable solvent for the purpose.

A minimum period of 24 hours shall be given after laying the flooring for developing proper bond of the adhesive.  During this period, the flooring shall not be put to service.  It is preferable to lay the PVC flooring after the completion of plastering, painting and other decorative finish works so as to avoid any accidental damage to the flooring.

When the flooring has been securely fixed, it shall be cleaned with a wet cloth soaked in warm soap solution (two spoons of soap in 5 liters of warm water).

14.39.3. Protection edging - Where the edges of the PVC sheets or tiles are exposed, as for example, in doorways and on stair treads, it is important to provide protection against damage of the flooring material.  Metallic edge strips may be used and should be securely fastened to the sub-floor to protect edges of the flooring.

14.39.4. Maintenance - PVC flooring subject to normal usage may be kept clean by mopping with soap solution using a clean damp cloth.  Water shall not be poured on the PVC flooring for cleaning purposes as the water may tend to seep between the joints and cause the adhesive to fail.  To maintain a good wearing surface and a good appearance, the flooring may be periodically polished.  When polish is applied frequently, a thick layer builds up which collects dirt and dust and is tacky to walk on.

If the traffic is light, the floor shall be given frequent brushing; regular polishing and an application of new polish every 4 to 6 weeks.  Under moderate traffic conditions the floor shall be given an occasional wash with a wet mop but no detergents shall be used so that the polish is not removed.  Application of polish may be done every one to three weeks.  PVC flooring should not be over-waxed; when this condition develops, the coatings should be cleared off with white spirit or paraffin and a light even coat of polish applied.  When the PVC flooring has been polished, it will remain bright for a considerable period if dry mop is applied each day.  It is this daily ‘dry polish’ that maintains the glossy surface.  After exceptionally heavy traffic, PVC flooring should be swept with a hair groom, rubbed with a mop or cloth frequently rinsed in clean water, and finally rubbed dry. 

14.39.5. Determination of sub-floor dryness.

14.39.5.1. General - Three tests for determining concrete sub-floor dryness are given in the Appendix.  It is intended that the first test should be carried out as a preliminary test as it is an approximate method only, and, while adequate to separate very wet slabs from those which are dry or nearly dry, will not discriminate

Satisfactorily between the latter two conditions.  Should this preliminary test indicate that the floor is ‘dry’ confirmatory tests should be made by one of the other two procedures given in 14.39.9.3 and 14.39.9.4.

14.39.5.2. Preliminary test

14.39.5.2.1. Materials – The following materials are required:

a) A sheet of glass about 30 x 30 cm or rubber mat or a sheet of polyethylene (not less than 0.1 mm thick) or the PVC flooring material of about 60 x 60 cm; and

b) Putty, adhesive plasticize or other suitable mastic for sealing the edges of the sheet material.

14.39.5.2. 2. Procedure - A sheet of glass, rubber or plastics material shall be placed on the concrete floor slab to be tested, and sealed thoroughly around all edges, using the mastic material.

After a period of not less than 24 hours, the covered portion of the concrete slab shall be inspected for signs of dampness.  If this area is even slightly darker in colour than the remainder of the slab, the floor shall be considered too wet.  A careful inspection is required, as in conditions of good ventilation; the difference in colour may rapidly disappear after the sheet has been lifted.

The test shall be made in several places on the slab, and repeated at regular intervals until no sign of dampness appears.  The floor should then be tested at several points by either the surface hygrometer method or the electrical resistance method until satisfactory results of floor dryness are obtained before the floor should be considered sufficiently dry.

14.39.5.3. Hygrometer test

Apparatus – A hygrometer is so constructed that when sealed to the floor with mastic or by other suitable means, the relative humidity of a small quantity of air confined between the slab and the case of the instrument is measured.

Procedure – The case of the hygrometer shall be carefully sealed to the slab and left for a period not less than 16 hours.  The relative humidity reading shall then be taken.

Results – The dryness of the concrete slab shall be considered satisfactory for conditions of laying the PVC flooring, if the relative humidity reading does not exceed 70 percent.

Electrical resistance test

Apparatus – The apparatus shall comprise the following:

a) Resistance meter – One of suitable range to enable it to be calibrated in terms of the moisture content of the slab in the range of 4 to 8 percent and having sufficient sensitivity to clearly distinguish changes of 0.5 percent.

b) Electrodes – Suitable to be inserted into 25 mm deep holes drilled in the concrete slab at a fixed distance apart.

c) A suitable contact medium of conductive jelly – For placing into the electrode holes.

Procedure – After drilling holes 25 mm deep in the concrete slab at a fixed distance, set the electrodes in the holes using the conductive jelly and connect to the electrical resistance meter.  The moisture content of the floor shall then be read off to the nearest 0.5 percent from the resistance meter.  Readings shall be taken from several widely distributed locations on the concrete slab.

Results – The concrete slab shall not be considered sufficiently dry if any one of the readings taken exceeds the following:

(a)Ploughed and tongued joints ; (b) Splayed, rebated, tongued and grooved joints ;(c)Rebated, tongued and grooved joints ; (d)Tongued and grooved joints ; (e)Rebated joints ; (f)Rebated and fitted joints ; (g)Splayed joints ; and  (h) Square butt joints.

For all these joints, screws shall be driven from top of floor boards to the joists below and then concealed by putty.

The pores of timber floor shall be sealed with a floor seal.

Annexure 14-A.1

ABRASION TEST FOR CONCRETE HARDENING COMPOUNDS (Clause 14.4.1)

Preparation of sample - 25 mm cylinder shall be prepared in ratio 1:2 (1 cement:  2 graded stone) aggregate 6 mm nominal size by weight one each with and without the admixture of concrete hardening compound shall be used in the proportion by weight of cement as recommended by the firm. The cylinder shall be placed inside a damp box for 24 hours and then cured in water for 27 days.  After that, they shall be subject to abrasion test on ‘Avery Abrasion Testing Machine’, using Emery Powder No.80 as the abrasing medium under the condition given below

Conditions of test

a) Area of rubbing surface shall be same in both the cylinders.

b) Age of cylinder - 28 days

c) Duration of Test  - 60 minutes

d) Total distance transverse during rubbing - About 2.4 km

e) Pressure on rubbing surface. - 0.04 kg/cm2

Results of tests - The following observations shall be made in both the cases

Composition of the Test specimen

Mean thickness rubbed away

Percentage loss in weight

Remarks - Percentage loss in weight in the case of cylinders with concrete hardening compound should not be more than 40% of the percentage loss in the case of cylinder without concrete hardening compound.

Annexure 14-A.2

TEST REQUIREMENTS AND PROCEDURE FOR TESTING PRECAST CEMENT CONCRETE / TERRAZZO TILES (Clause 14.11.1 & 14.12.1)

Sampling - The tiles required for carrying out test described below shall be taken by ‘random sampling’.  Each tile sample shall be marked to identify the consignment from which it was selected.

Minimum quantity of tiles for carrying out the test and frequency of test shall be as specified in the list of Mandatory Test.  The number of tiles selected for each mandatory test shall be as follows;

a) For conformity to requirements on shape and dimensions,

   wearing layer, and general quality. - 12 tiles

b) For wet transverse strength test  - 6 tiles

c) For resistance to wear test - 6 tiles

d) For water absorption test - 6 tiles

Note:1) The tests on the tiles shall not be carried out earlier than 28 days from the date of manufacture.

(2) The tiles selected for (a) may as well after verification of requirements, be used for (b).

Wet transverse strength test - Six full size tiles shall be tested for the determination of wet transverse strength.  When tested according to the procedure laid down in Appendix ‘E’ of IS: 1237, the average wet transverse strength shall not be less than 3 N/mm2 (30 kgf/cm2).

Resistance to wear test - Not less than twelve specimens shall be prepared as described.  From the tiles selected in accordance with B.1.  When tested in the manner as specified their average wear shall not exceed 3.5 mm and the wear on any individual specimen shall not exceed 4 mm.

Preparation of test specimens - The test specimens shall be square in shape and of size 7.06 cm x 7.06 cm (i.e., 50 sq. cm in area).  They shall be sawn off one only from each tile, preferably from the central part of the tile.  The deviation in the length of the specimen shall be within ± 2 per cent. The surface to be tested shall be ground smooth and filling removed.

Apparatus and accessories

Abrasion testing machine - The abrasion test of specimens shall be carried out in a machine conforming essentially to the requirements described in IS: 1237-1980 (Appendix “F”).  The abrasive powder used for the test shall conform to the specification given below

The abrasive shall have an aluminium oxide content of not less than 95 per cent by weight. The grains shall be of rounded shape and shall generally pass through IS Test Sieve 25 and be retained on IS test Sieve 20. The combined content of larger grains retained on IS Tests Sieve 25 and of smaller grains who’s finest is not limited, shall not exceed 10 per cent.  The specific gravity of the grains shall be between 3.9 and 4.1.  The grains shall generally have a hardness of 9 in Mohr’s scale.

Measuring instruments - A suitable instrument capable of measurement to accuracy of 0.01 mm shall be used for determining the change in the thickness of the specimen after abrasion.

Procedure of test - The specimen shall be dried at 110 degree C for 24 hours and then weighted to the nearest 0.1 gm. The specimen after initial drying and weighing shall be placed in the thickness measuring apparatus with its wearing surface upper most of the reading of the measuring instrument taken.

The grinding path of the disc of the abrasion testing machine shall be evenly strewn with 20 gm of the abrasive powder. The specimen shall then be fixed in the holding device with the surface to be ground facing the disc and loaded at the centre with 30 kg. The grinding disc shall then be put in motion at a speed of 30 rpm. After every 22 revolutions, the disc shall be stopped, the abraded powder shall be removed from the disc and fresh abrasive powder in quantities of 20 gm applied each time.  After 110 revolutions, the specimen shall be turned about the vertical axis through an angle of 90 degree and then the test continued under the same conditions until 220 revolutions have been completed altogether. The disc, the abrasive powder and the specimen shall be kept dry throughout the duration of the test.  After the abrasion is over, the specimen shall be re-weighed to the nearest 0.1 gm.  It shall then be placed in the thickness measuring apparatus once again in the identical manner and the reading taken with the same position and setting of the dial gauge as for the measurement before abrasion.

Determination of wear - The wear shall be determined from the difference in readings obtained by the measuring instrument before and after the abrasion of the specimen.  The value shall be checked up with the average loss in thickness of the specimen obtained by the following formula.

            (W1 – W2) V1

t = 10 x ---------------------------------

               W1 X A

Where

t = Average loss in thickness, in mm;

W1 = Initial weight, in gm of the specimen;

W2 = Final weight, in gm of the abraded specimen

V1 = Initial volume, in C. C., of the specimen, and

A = Surface area, in sq. cm of the specimen.

Water absorption - At the time of delivery to the site of the work, not less than six full tile specimens, selected in accordance with B1, shall be prepared and then tested as described below, their average percentage of water absorption shall not exceed ten.

Preparation of specimen - Full size tiles shall be used for this test.  They shall be immersed in water for 24 hours, then taken out, wiped dry and tested for water absorption.

Procedure of test - Each tile shall be weighed immediately after saturation and wiping.  The tile shall be oven dried at a temperature of 65 ± 1 degree C for a period of 24 hours, cooled to room temperature and re-weighed.

Determination of water absorption - The water absorption per cent by weight for each tile shall be determined as follows

On oven dry basis water per cent by weight =   (W1 – W2) x 100

                                                                          -----------------------

                                                                                     W2

Where

W1 = Weight in gm of the saturated specimens, and

W2 = Weight in gm of the oven dried specimen

The average value for percentage water absorption shall be calculated for the whole number of tiles tested.

Annexure 14–A.3

SPECIES OF TIMBER RECOMMENDED FOR SLATS, FLOOR BOARDS AND PARQUET FLOORS (Clause 14.37.10)

Name

Hardness

Name

Hardness

1

Gurjan

135

14

Kindal

95

2

Rohini

130

15

Pali

90

3

Padauk

130

16

Kokko

90

4

Satinwood

130

17

Rosewood

90

5

Maniawga

125

18

Kassi

85

6

Axlewood

120

19

Sissoo

85

7

Kala Siris

120

20

Piney

85

8

Bijasal

100

21

Jarul

80

9

Laurel

100

22

Hollock

75

10

White chuglam

100

23

Anjan

70

11

Teak

100

24

Fir

65

12

Lendi

95

25

Cypress

60

13

White Cedar

95

26

Machillus

55

Annexure 14-A.4

SPECIFICATIONS FOR DETERMINATION OF SUB-FLOOR DRYNESS (Clause 14.25.3.)

General - These tests for determining concrete sub-floor dryness are given in this appendix. It is intended that the first test should be carried out as preliminary test as it is an approximate method only, and is adequate to separate very wet slabs from those which are dry or neatly dry, but will not discriminate satisfactorily between the latter two conditions. Should this preliminary test indicate that the floor is ‘dry’ confirmatory test should be made by one of the other two procedures as given.

Preliminary test - The following materials are required

a) A sheet of glass about 30 x 30 cm or rubber mat or a sheet of polyethylene (not less than 0.1 mm thick) or the PVC flooring material of about 60 x 60 cm and

b) Putty adhesive plasticine or other suitable mastic for scaling the edges of the sheet material.

Procedure - A sheet of glass, rubber or plastic materials shall be placed on the concrete slab shall be placed on the concrete floor slab to be tested, and sealed thoroughly around all edges, using the mastic material.

After a period of not less than 24 hours, the covered portion of the concrete slab shall be inspected for signs of dampness. If this area is even slightly darker in colour than the remainder of the slab, the floor shall be considered too wet. A careful inspection is required, as in conditions of good ventilation; the difference in colour may rapidly disappear after the sheet has been lifted.

The test shall be made in several places on the slab, and repeated at regular intervals until no sign of dampness appears. The floor should then be tested at several points by either surface hygrometer method or the electrical resistance method until satisfactory results of floor dryness are obtained before the floor should be considered sufficiently dry.

Hygrometer test

Apparatus - A hygrometer is so constructed that when sealed to the floor with mastic or by other suitable means, the relative humidity of a small quantity of air confines between the slab and the case of the instrument is measured.

Procedure - The case of the hygrometer shall be carefully sealed to the slab and left for a period not less than two hours. The relative humidity reading shall then be taken.

Results - The dryness of the concrete slab shall be considered satisfactory for conditions of laying the PVC flooring, if the relative humidity reading does not exceed 70 per cent.

Note: The instrument shall be so placed that sunlight does not fall on it, as this may produce a false low reading.

Electrical resistance test

Apparatus - The apparatus shall comprise the following

  1. Resistance Meter -  One of suitable range to be calibrated in terms of the moisture content of the slab in the range of 4 to 8 per cent and having sufficient sensitivity to clearly distinguish changes of 0.5 per cent.

Annexure 14-A.5

SPECIFICATIONS FOR BITUMEN MASTIC FOR FLOORING FOR INDUSTRIES HANDLING LPG AND OTHER LIGHT HYDROCARBON PRODUCTS (Extract of IS: 13026-1991)

1.  Scope

1.1. This Annexure specifies requirements of bitumen mastic flooring for industries handling LPG and other light hydrocarbon products.

1.2. This Annexure is also applicable for explosive and crackers manufacturing factories, ordinance factories, ammonia depots, etc.

1.3. This Annexure is not applicable for less volatile materials such as kerosene, diesel and lubricating oil.

2.  References - The Indian standards listed in 8 are necessary adjuncts to this standard.

3. Terminology - For the purpose of this standard terminologies given in IS: 334-1982 shall apply.

4.  Materials

4.1. Bitumen- Properties of bitumen conforming to IS: 702 -1988 shall be as specified below

Physical properties of bitumen (Clause 4.1)

Sl. No.

Characteristic

Requirement

Method of test

i

Softening point ( ring 65 to 1000 c and ball method )

65 to 1000 C

IS: 1205-1978

ii

Penetration at 270 C in 100 cm

10 to 40

IS: 1203-1978

iii

Loss on heating, % Max

0.3

IS: 1212-1978

iv

Solubility in CS2, % Min

99

IS: 1216-1978

v

Dctility at 270C, Min

2

IS: 1208-1978

4.2. Aggregates and fillers - Aggregates and fillers used in preparing bitumen mastic should be lime stone and other carbon black / graphite materials.   The lime stone should have calcium carbonate content of maximum 75 percent.  The combined grading of aggregates shall be as specified below

Grading of Aggregates and Fillers

Sieve Designation

Percentage by Mass

Passing IS Sieve

Retained on IS Sieve

90 microns

-

45 to 55

212 microns

90 microns

10 to 30

600 microns

212 microns

10 to 30

2:36 mm

600 microns

6 to 20

-

2:36

Nil

5.  Composition - Bitumen mastic composition is made by adding suitable materials like carbon black / graphite of conducting type. The bitumen content shall be between 13 and 18 percent by mass of the total mastics. Carbon black / graphite content shall be finer than 90 micron IS sieve with certain content more than 60 percent by mass.

5.2.   Preparation of bitumen mastic - The aggregates and fillers shall be heated in a mastic cooker to a temperature of 120 to 1500C and then the required quantity of bitumen heated to 170 to 1800C added to it.  These shall be mixed and cooked for about 3 hours until the homogeneous mass is obtained taking care t hat the temperature does not exceed 2050C at any time.

6.  Properties - The hardness number of bitumen mastic as laid and tested as per method described in 9 shall be 4 to 12 at 350C. The resistance to products after being manufactured according to 5.2 and when tested in accordance with 7 shall have electrical resistance between 5 x 144 ohms and 2x106 ohms.

7.  Test procedure for measuring electrical resistance

7.1. Preparation of sample - In preparing sample for test, mastic as laid shall be filled directly from the mixer at the time of laying, into moulds which re not less than 100mm in diameter or 100mm square and float finished. The sample, which shall be taken in duplicate, shall be molded to a thickness of 25 mm.  Where it is necessary to perform test on samples taken out from the floor, special precautions should be taken to ensure that the base is level and the sample is of uniform thickness.  The sample should not be re-melted.

7.2. Preparation of the Surface - The surface to be used in test shall be cleaned by rubbing with dry Fuller's earth using a clear pad of cotton wool, care being taken to avoid straining the material.

7.2.1. After all traces of the powder have been cleaned away, the surfaces shall be wiped over with a pad moistened with distilled water and rubbed dry with a clean cloth.

7.3. Test procedure - Immediately after the preparation of the surface, liquid electrodes and metal contacts as described in 10 shall be applied as given in 11.  It shall then be kept at a temperature of 27 ± 20C at a relative humidity of less than 70 percent, and the resistance test as specified shall be carried out after a period of not less than 15 minutes or more than two hours.  As some materials are sensitive to moisture, great care shall be taken to avoid breathing on the samples prior to and during the resistance test.

8. List of referred Indian standards  (Clause 2.1)

IS No.

Title

IS No.

Title

334-2002

Glossary of terms relating to bitumen and tar

( second revision )

1208-1978

Methods of testing tar and bituminous materials : Determination of ductility

( first revision )

702-1988

Industrial bitumen

( second revision )

1212-1978

Methods of testing tar and bituminous materials : Determination of loss on heating  ( first revision )

1203-1978

Methods of testing tar and bituminous materials: Determination of penetration

( first revision )

1216-1978

Methods of testing tar and bituminous materials: Determination of solubility in carbon disulphide or trichloro-ethylene ( first revision )

1205-1978

Methods of testing tar and bituminous materials: Determination of softening point ( first revision )

 

 

9. Method for determining hardness number (Clause 6.1)

9.1. Definition of Hardness Number - The hardness number is the figure denoting the depth, in hundredths of a centimeter, to which a flat-ended indentation pin in the form of a steel rod 6.35 mm in diameter will penetrate the mastic under a load of 317 N, applied for 1 minute, the temperature being maintained at 350 ± 0.50C.  This load is equivalent to 10 N/mm2 and is conveniently applied by means of a lever giving a suitable mechanical advantage.

9.2. Apparatus

The apparatus employed should be capable of fulfilling the above requirements accurately.  One convenient form of apparatus is shown in Fig.1

A – Yoke, stalk and tray

J – Indicating needle

B – Weight (central hole)

K – Beam support yoke

C – Weight (slotted)

L – Support bracket

D – Indentor pin spindle

M – Calibrated dial

E – Lock lever

N – Water bath

F – Spindle head

P – Control for water stirrer

G – Adjusting nut

R – Control for heater blade and thermostat

H – Beam

S – Bath illuminator

Fig 1 A type of apparatus for hardness testing

9.3. Method

9.3.1. In order to ensure that the test results are reproducible, particular attention is called to the points given in 9.3.2 to 9.3.5

9.3.2. Samples - In preparing samples for test, the mastic as laid shall be filled directly from the mixer at the time of laying, into moulds which are not less than 100mm in diameter or 100mm square and float finished.  The samples, which shall be taken in duplicate, shall be moulded to a thickness of 25 mm.  Where it is necessary to make a test on samples cut from the floor, special precautions should be taken to ensure that the sample is of uniform thickness and that the base is level.  The samples should not be remitted.

9.3.3. Test temperature - For the purpose of this standard, the sample shall be cooled for not less than three hours in air or not less than one hour in cold running water.  It shall then be immersed in water at a temperature of 35 ±  0.50 C for at least one hour immediately prior to testing and shall be maintained at that temperature during the test.

9.3.4. Adjustment of pin - Before the load is applied, the indentation pin shall be adjusted lightly but firmly in contact with the surface.  The pressure should not be greater than necessary to prevent lateral movement of the specimen.

9.3.5. Testing - The requisite load shall then be applied for exactly 1 minute and the depth of indentation recorded in hundredths of a centimeter.

9.3.6. Test results - Test points shall be not less than 25mm apart and not less than 25mm from the edge.  At least five readings shall be taken and the results averaged.  If any result differs from the mean by more than two hardness’s determined, except that if there are fewer than four results to be averaged the sample shall be discarded and the test shall be made on another samples.

10. Liquid electrodes and contacts and testing instruments (Clause 7.3)

10.1. Liquid electrodes - Liquid electrodes shall be formed on the surface by means of a conducting liquid. This shall consist of:

Anhydrous polyethylene glycol of mol wt 600 - 800 parts

Water - 200 parts

Soft soap - 1 part

Potassium chloride - 10 parts

The electrode area shall be completely wetted and remain so until the end of the test.

Clean metal contacts shall be applied to the wetted areas so that the contact area is approximately of the same size as but not greater than the wetted area.  The surface of the product shall not be deformed either during the application of the contacts or during the test.

10.2. Testing instruments - The test shall be carried out with an insulation tester having a nominal open circuit voltage of 500 V d.c. or, with any suitable instrument known to give comparable results.  For values of resistance above 106 ohms, an instrument with nominal open circuit voltage of 1000 V d.c may be used. The instrument shall be sufficiently accurate to determine the resistance within 5 percent and shall not dissipate more than 3 W in the specimen.  The voltage shall be applied for no longer than is necessary to carry out the test in order to reduce the risk of overheating the test piece.

11. Tests for electrical resistance for bitumen mastic floor (Clause 7.3)

Procedure - The test is performed on one surface.  Apply liquid electrodes to two areas, each approximately 25 mm2, located on the same surface to be tested and situated so that the dry distance between the facing edges is 50 ± 6 mm.  Apply the metal contacts to the wetted areas and measure the resistance. This test shall also be performed on the sample to measure the electrical resistance across the surface. 

Annexure 14-A.6

SPECIFICATIONS FOR LAYING OF BITUMEN MASTIC FLOORING FOR INDUSTRIES HANDLING LPG AND OTHER LIGHT HYDROCARBON PRODUCTS (Extract of IS: 13074-1991)

1.  Scope

1.1. This Annexure lays down the procedure for laying bitumen mastic flooring for industries handling LPG and other light hydrocarbon products.

2.  Reference - The Indian standard IS: 13026-1990 ' Specification for bitumen mastic flooring for industries handling LPG and other light hydrocarbon products ‘is a necessary adjunct to this standard.

3. Design consideration - Bitumen mastic is jointless and impervious to the transmission of moisture.  In designing the bitumen mastic flooring for hydrocarbon services, consideration shall be given to the anticipated service conditions as specified in IS: 13026-1990

4.  Thickness - The total thickness to which bitumen mastic should be laid shall be 20 mm to 25mm or as mutually agreed upon by both parties depending on actual conditions.

5.  Material - Bitumen mastic shall conform to the requirements given in IS: 13026-1990

5.2. The bitumen mastic may be delivered to the site in the molten state and immediately laid.

6.  Equipment - The equipment shall consist to bitumen boiler, a mechanically agitated mastic cooker and other accessories.  The equipment shall be used near the site, so as to prevent cooling of the molten material.

7. Construction - The base on which the bitumen mastic is to be laid shall be stable to receive the mastic and to sustain the anticipated load on it.

7.2. Preparation of the Base - The base shall have an even and dry surface which has been roughened with stiff broom or wire or coir brush and should be free from ridges and hollows.  The base may be provided with suitable slope if needed for drainage of rain water etc.,

7.3. Laying

7.3.1. Transport of Molten Material - The molten mastic shall be carried in flat mortar pans.  The pans are sprinkled with lime stone dust, to prevent sticking of mastic.  Grease or oil shall not be used.

7.3.2. Spreading - Bitumen mastic should be laid in bays in one or more layer.  The specified thickness is maintained by suitable hand tools, gauges, straight edges, band levels, etc. The bubbles formed during laying should be punctured and the area rectified while mastic is hot. Multi-layer work should be treated in same manner as that of single-layer, care being taken to arrange that the joints in successive layers are staggered.

7.3.3. Protection of the surface - The laid surface shall be protected from damage due to movement of heavy load, spillage of oils, etc.  Bitumen mastic surface should not be used for preparation of cement concrete mixes or mortars.

7.3.4. Opening to traffic - The mastic flooring should not be opened to traffic until the material has cooled down to ambient temperature of the surrounding atmosphere.

8.  Repairs - Damaged area shall be cut rectangular and replaced with new mastic.  Blow lamp techniques to remove damaged layer are preferred.

9.  Maintenance - The bitumen mastic flooring requires little maintenance.  Dirt and dust should be periodically removed with lukewarm water and detergent.  Oils, fats and grease spilled, should be removed immediately.

Annexure 14-A.7

SPECIFICATIONS FOR LINOLEUM SHEETS (Clause 14.37.4)

Materials - Linoleum shall consist of a composition pressed on Hessian backing. There shall be adequate Hessian between the composition and the Hessian backing. The composition shall contain oxidized or polymerized, linseed oil conforming to IS: 75 specification for linseed oil or other suitable drying oiler with necessary driers, fossil and /or resin intimately mixed with ground cork or wood flour or both and pigments. The Hessian used for the backing shall have not less than 43 ends and 33 shots per decimeter. A piece 90 x 100 cm will weigh not less than 220 gram. Unless specified otherwise, the paint when used for painting the Hessian backing shall conform to IS:  640.

Dimensions - The linoleum shall be manufactured to the following thickness

Thickness (mm)   Type

6.7                          All

6.0                  Plain and Marble

4.5                         All

3.2                         All

2.0                         All

1.6               Moire and Jaspe

Measurement and thickness - The thickness of linoleum shall be measured with a micrometer gauge or a dial micrometer gauge having a flat foot and capable of reading up to 0.01 mm. The foot of the micrometer gauge shall exert a pressure of 1.5 kg/cm2 on the linoleum surface.  The measurement shall be made at least at 16 points and the mean value shall not vary by more than 0.1 mm from the specified thickness.

Width - Unless otherwise, the width of the linoleum shall be 2 m with a tolerance of ± 1.5 mm.

Length - Unless specified otherwise, all types of linoleum of all thicknesses other than 6.0 and 6.7 mm thicknesses shall be supplied in rolls of length of not less than 5.5 m.  In case of 6.0 and 6.7 mm thicknesses linoleum, the length shall be not less than 3 m.  The length shall be measured to the nearest centimeter.

Colour - The composition of plain linoleum shall be of uniform colour extending evenly throughout the thickness from the surface to the Hessian backing to form a sheet of approved colour.

In moire, jaspe and marble sheet linoleum portion of the mix shall be of different colours and shall be compressed into a single sheet.  The several colours shall extend from the surface to the base in random relation to form a variegated surface showing an approved pattern.

Finish - The surface of the linoleum shall be smooth, uniform and free from indentations and protrusions. The Hessian backing shall be unpainted unless otherwise specified.

Annexure14-A.8

SPECIFICATIONS FOR LAYING, FIXING AND MAINTENANCE OF LINOLEUM FLOORS

(Extract of IS: 1198-1982) (Clause 14.37.4.4)

0.1. Linoleum provides a satisfactory floor for residential and public buildings, railway coaches, ships, etc. It is also suitable for most types of non-industrial floors. In light industry such as in electronic industry, linoleum flooring may be used, as the risk of damage by cutting, to which linoleum is vulnerable, is small. However, if linoleum gets wet, it expands and eventually rots. This standard has been prepared with a view to guiding the users in regard to laying, fixing and maintenance of linoleum floors.

0.2. This IS standard has incorporated improvements found necessary in the light of usage of the standards and the suggestions made by various bodies implementing it. In this separate clause on suitability of linoleum for various conditions of use has been added and the materials used as underlay for aspects like preparation of sub floors, fixing of under lays, laying of linoleum has been dealt with, in detail. This also suggests the laying and fixing method of linoleum in tile form.

1. Scope

1.1. This Annexure recommends details of work necessary for laying, fixing initial treatment, and subsequent maintenance of linoleum flooring in sheet and tile form.

2. Terminology

2.1. Sub-floor - The surface on which flooring is to be laid.

2.2. Underlay - A layer of prefabricated material or in-situ filling on the sub-floor to provide a smooth level surface to receive the flooring.

3. Necessary information

3.1. For the efficient planning and execution of the work, detailed information with regard to the following is necessary:

(a) Purpose for which the floor is to be used; (b) Floor area to be covered; (c) Location and size of

openings and ducts, drainage outlets, if any, to be left out; (d) Details of the sub-floor, (e) Type of soil in the sub-base and any seepage problem.

3.2. All the information stated in 3.1 shall be made available by the appropriate authority responsible for the construction of the whole building to those who are entrusted with the work of laying linoleum

floor finish before the work is started. Necessary drawings and instructions for preparatory work shall also be given where required.

3.3. Arrangements shall also be made for the proper exchange of information between those engaged in laying the floor and all others whose work will affect or will be affected.

4. Suitability

4.1. Linoleum is suitable for use in domestic buildings, and those of non-industrial character where the traffic is expected to be essentially pedestrian. However, the following factors must be considered before it is being laid. The thicknesses recommended are 4.5 and 3·2 mm for commercial and institutional buildings respectively and 1.6 mm for domestic or where traffic is low.                                   

4.1.1. Resistance to rising damp - Linoleum requires an adequately dry sub-floor. If inconveniences of damp proofing are not acceptable, linoleum should not be used.

4.1.2. Exposure to weather - Linoleum is not suitable for installation except where it is wholly inside a building.

4.1.3. Resistance to chemicals - Linoleum is resistant to oils, fats and greases. Thicker gauges shall be used where heavy traffic is expected.

4.1.4. Indentation resistance - Linoleum is not resistant to indentations particularly from heels or static load. Cork tile will withstand heavy foot traffic but indents if heavy objects are left in one position for some time or pushed.

4.1.5. Slip resistance - Linoleum when highly polished or wet can become dangerously slippery. The polish with a reduced tendency to slipperiness may be used. The cork tile flooring provides a slip resistant surface except when liquid wax polish is applied over a seal.

5. Material

5.1. Flooring - The flooring shall comply with the requirement specified in IS: 653-1981.

5.2. Underlay - The underlay may be as given below:

a) For Timber Sub floors:

i)  Plywood at least 4 mm thick (see IS: 303-19751)

ii) Hardboard at least 3 mm thick see IS: 1658-19771)   and

iii)  Fibre based bitumen felt I mm thick (see IS: 1322-1970)

b) For Concrete Sub floors:

i)  Bitumen mastic (see IS: 1195-1978) and

ii)  Bitumen (see IS: 1580-1969).

5.3. Adhesives - The type of adhesive to be used and the manner of use shall be those recommended by the floor covering manufacturer and the adhesive shall be compatible with the floor covering and suitable for bonding the floor covering to the underlay or sub-floor. Adhesives shall not

be considered effective as damp-proof membrane. Information on types of adhesives is given below.

5.3.1. Vegetable and casein glues - Vegetable  (starch) glue is usually in the form of a paste, and casein glue usually in the form of a powder which is mixed with water before use Both the types are spread on the base and the linoleum is pressed on to it Vegetable adhesives are effective but take some time to harden. They are unsuitable for situations where a lot of water is likely to be spilt on the linoleum. These glues are liable to attack by fungi.

5.3.2. Lignin pastes

5.3.2.1. Lignin, a by-product of paper manufacture is mixed with clay to form an adhesive which is applied thinly to the base and the linoleum pressed on to it. It resembles starch and casein glues but it is more resistant to water.

5.3.3. Gum-spirit adhesives - Adhesives made from gum or resin, filler and methylated spirit are characterized by their strong smell. The adhesive is spread on the base previously rendered dry. As the spirit evaporates, a skin forms on the surface; the linoleum is pressed into the adhesive before the skin becomes too thick. The linoleum can, therefore, be spread only a few square metres at a time.

Any excess of spirit evaporates slowly through the linoleum or is absorbed by the sub-floor. Gum-spirit adhesives are resistant to damp but are likely to be attacked by dilute alkaline solutions such as those that rise through wet concrete.

5.3.4. Bitumen-rubber emulsions - This type of adhesive is a dark coloured emulsion of rubber and bitumen or coal-tar pitch in water. There is no smell of solvent in this case. The water in the adhesive must evaporate before the linoleum is laid, as there is a risk of blistering if the linoleum absorbs the water. The evaporation is noted by the colour of the adhesive, which changes from chocolate to black. When the colour is black, it is safe to lay the linoleum. This type of adhesive and the solution type described under A-5 are what may be called 'one-chance' adhesives; when the linoleum is placed on them it is fixed and cannot be slid into position. The bitumen-rubber emulsions are resistant to water and, when set, are water-repellent. When used as adhesives they should not, however, be taken to serve as damp-proof courses.

5.3.5. Bitumen-rubber solution - Bitumen-rubber solution adhesive is dark coloured, of thick consistency and is recognizable by the strong smell of petroleum solvent.  The solution is applied both to the back of the linoleum and to the floor and the solvent allowed to evaporate before the linoleum is laid. During this period, as a precaution against fire, the room shall be well-ventilated and no smoking or naked flame shall be allowed. As adhesives, they are resistant to water and are water-repellent but do not serve as damp-proof courses. 

6. Preparation of sub floors

6.1. The linoleum flooring gives maximum, service if laid on a firm base. Evaporation of the moisture from the sub floor cannot take place once linoleum is laid. Therefore, it is important that sub floors should be thoroughly dry before laying of the linoleum. An irregular, sub floor surface creates poor adhesion between the sub floor and the linoleum. Therefore, the sub floor should always be smooth and level. Recommended treatments for different sub floors are given under 6.2 to 6.4.

6.2. Timber - All timber sub floors shall be sound, rigid, level and dry. The timber should be at equilibrium moisture content at the time it is covered with the underlay or the floor covering. A timber floor should always be well ventilated, to discourage fungal attack.

6.2.1. New timber floors - In the case of new construction, seasoned and treated timber shall be used and shall be of tongued and grooved boarding. Boards shall be narrow and of equal width (say 100mm). Boards of unequal width have various degree of shrinkage. Before fixing the linoleum, all nail heads on the timber sub floor shall be punched down, regulations planned off and the holes filled with plaster, plastic wood or similar fillers. After the boards have been nailed to the joists, the floor is usually firm enough for direct laying of the linoleum, but however, under lays such as plywood or hardboard or fibre based bitumen felt may be used prior to fixing of the linoleum to prevent any movement in the boards. Suspended timber floor shall be adequately ventilated with a minimum air gap below the underside of the joist to stop the growth of rot. Wood blocks and boarded floor on concrete on the ground shall not be covered with linoleum unless an efficient damp-proof membrane in the concrete below the blocks or boards has been provided.

6.2.2. Existing timber floor - In the case of an existing timber floor, covered with boarding when it is not possible to obtain an even surface or in cases of dry rot, the use of diagonal boarding is recommended, after removing and replacing some of the badly affected boarding and filling in the cracks with plastic wood or similar filler and after disinfecting the floor. Alternatively, plywood topping on the existing boarding also gives an even surface. It is important, however, to see that the floor is well ventilated, and if it is a ground floor, by means of air-ducts in the outer walls and sleeper walls with honeycombed pattern for free circulation of air.

6.3. Concrete - All concrete sub floors may be finished with cement and sand or fine concrete screed laid according to the recommendations of IS: 2571-1970. The sub floor surface shall be smooth and flat. Concrete is not completely impervious. As moisture either in liquid or in vapour form and rising damp may cause damage to linoleum, concrete sub floor intended as a base for linoleum shall contain an effective damp-proof course. The damp-proof course shall be laid in any one of the ways given below.

6.3.1. The most effective treatments for existing floors to protect it against rising damp is a layer of bitumen mastic not less than 15 mm thick laid over the sub floor according to the recommendations given in 1S:1196-1978.

6.3.2. For new work the sub floor shall be laid as per the recommendation given in IS: 2571-1970. Information on the limitations of damp-proof materials is given below.

A

Water proofing materials

Properties / limitations

1.

Bitumen mastic laid according to IS: 1196-1978

Impervious to the transmission of moisture.  May be used as floor finish or as an underlay; where concrete is laid direct to earth, an isolating membrane should be used.

B

Sandwich Membranes

 

1

Bitumen mastic

Impervious to moisture

2

Bitumen felts

When joints are properly sealed, it is impervious

3

Hot applied bitumen

When laid on a primed surface with suitable thickness it may be regarded as impervious; care shall be taken to avoid pin holes

4

Cold applied bitumen, bitumen rubber emulsion

Repeated application can form an impervious layer; care in workmanship and maintenance is needed.

6.3.3. Waterproofing materials mixed with concrete do not produce an effective barrier against rising damp.

6.3.4. Before linoleum is laid, ample time shall be allowed for the water to dry from both suspended and ground concrete floors. It is difficult to specify the period required as this depends on weather and on the quality and thickness of the concrete, but a period of 4 to 8 weeks at least shall be allowed for drying under normal conditions. This time may be reduced if the building is heated and if the ventilation is good.

6.3.5. In new work, the finish required for laying linoleum should be usually produced with a steel trowel on a screed applied to the base concrete. The finish may, however, be produced on the base concrete itself if a power-float is used. With old concrete, if the surface is only slightly uneven, the holes shall be filled with a skim layer of proprietary bitumen-cement or latex-cement leveling coat. For rougher surfaces, an underlay of asphalt, bitumen-cement or latex-cement is necessary. Of these, latex-cement can be used in the least thickness. If sub-floors are dusty, it is a-safe practice to use a primer such as bitumen emulsion before using an adhesive. Concrete hardeners or densities may also be used with advantage to bind the surface of the screed.

6.4. Other sub floors - Some bases such as clay tiles, concrete tiles or terrazzo are unaffected by dampness, but may be sufficiently porous to allow moisture to pass through to the back of the floor finish. These bases shall be damp-proofed when necessary by using under felt. Bases such as magnesium oxy chloride in good conditions are suitable for receiving linoleum but are adversely affected by dampness rising through concrete from the ground and shall not be covered with a damp-proof layer. Unless it can be established that there is an effective damp course below these materials, they shall be removed before laying the Linoleum. Bitumen mastics are excellent bases to receive linoleum but solvent type adhesives may soften the mastic and mastics, which are soft and are likely to be dented, are not suitable for linoleum.

7. Laying

7.1. General - Linoleum should be stored in room temperature of not less than 200C for at least 48 hours before it is unrolled. It shall be laid out flat for several days before it is cut to size because, after being unrolled, it shrinks in length and expands in width. As the humidity in the room is usually greater than that at which the linoleum was rolled, it absorbs moisture and being unrestrained, expands. If the linoleum is cut to fit closely round the skirting, it will often be found necessary after a time to retrim the material. When two widths of linoleum meet, they shall be left with one overlapping the other until expansion has stopped and then cut to fit. Cork tile should be dimensionally stable in the condition of use. In order to achieve this, tiles should be removed from the cartons at least 48 hours before lying is to commence and be distributed in the room in humidity and temperature conditions similar to those likely to prevail in occupation.

7.1.1. Before starting to lay the linoleum, the position and depth of cables, water pipes in the floor screed, etc, should be ascertained and all preliminary work should be completed. The sub floor should be firm and dry and tested for dampness as given in 7.1.1.1 to 7.1.1.4.  Dusty sub floor should be swept and porous sub floors should be primed as recommended by the adhesive manufacturer.

7.1.1.1. The tests as prescribed shall be conducted to determine the dampness of floor while laying linoleum.

7.1.1.2. Rubber test - Place one square meter of rubber matting and place it loosely, with the smooth side down, on the floor to be tested. The matting shall be left for twenty-four hours for ordinary floors and forty-eight hours for unusually smooth floors. If, after this period, on removing the matting the concrete shows a dark patch, it is an indication that the floor is not sufficiently dry to receive linoleum.

7.1.1.3. Anhydrous copper sulphate test - This test is much more rigorous than the rubber test and is thus more certain. Take an ordinary piece of window glass about 40 cm square, lay the glass on the area of the floor to be tested and mark the floor round the glass with pencil. Remove the glass and lay an even heading 12 mm thick, of well-worked putty inside the pencil line. Spread evenly one tea spoonful of anhydrous copper sulphate powder inside the putty and cover immediately with the glass, pressing the glass firmly into the putty, so that the copper sulphate is kept air-tight. The copper sulphate should be white when it is put in position; if after six hours it has turned green or blue it is clear indication that the concrete is still too damp to receive linoleum.

7.1.1.4. Moisture meter test - Floors may be tested for dampness by means of a pocket hygrometer placed in contact with the floor. The edges shall be sealed with putty if the floor is rough. The humidity of the enclosed air is read directly on the scale of the hygrometer. The air usually takes not less than the instrument in position overnight and takes the reading in the morning. As a general rule, a value of 70 to 75 shall be below 80 before it can be assumed that the concrete above the damp course has dried sufficiently for it to be suitable for the fixing of linoleum.

7.2. Adhesives - The linoleum shall be laid either loose or fixed to the sub floor by means of suitable adhesives. Any priming coat should be allowed to dry before the adhesive is spread. Adhesives are spread with a closely notched trowel as recommended by the manufacturer to ensure even the coverage of the sub floor to the correct thickness. It is essential that where low flash solvent adhesive (containing petroleum or naphtha) are used, the use of naked lights should be prohibited in the vicinity of the laying operations. The area shall be well ventilated even when non-flammable solvents are used in the adhesives. Smoking shall be prohibited.

7.3. Fixing of under lays - Plywood, hardboard shall be securely fixed to the sub floor in the form of sheets using staple, and nails. Fixing shall start at the centre of the sheet and secured at 100mm intervals around the side. All nail heads shall be finished flush with the surface. Joint lines shall be staggered and every effort shall be made to prevent coincidence in joints in the sheet and timber base. A suitable gap shall be left between the sheets for possible expansion due to atmospheric changes. Except where recommended, hardboard may be laid with the smooth face uppermost. When a felt underlay is used all surfaces to be covered shall be thoroughly cleaned free from dust and dirt. No surface shall be cleaned with water as dryness is essential.

Bitumen felts shall be cut to size and fixed with the adhesives as recommended by the manufacturer. It shall be butt jointed and laid across the boards so that the joints run in a direction at right angle to the joints in linoleum. The joints shall not coincide with those in linoleum sheets. After fixing, the felt shall be smoothed down and well rolled. Bitumen mastic shall be laid in accordance with the recommendations as given in IS: 1196-1978, where the mastic is used as underlay and damp-proof coarse, care shall be taken to connect it with the damp proof course in the walls. Other underlay as given in 5.2 should be laid as per the recommendations of the manufacturer.

7.4. Fixing - The base over which the linoleum is to be fixed shall be thoroughly cleaned free from dirt and dust, chemicals, oils, paints, etc. The adhesive shall be spread evenly with a trowel as recommended by the manufacturer. The linoleum shall be firmly pressed into the adhesive within the recommended setting time of adhesive. To give maximum adhesive contact and to secure a bond, the material shall be well rolled with a floor roller weighing approximately 70 kg working from centre to the walls. If necessary the linoleum may be loaded with sand bags at various points until the adhesive has gripped. When laid directly on concrete, it is desirable to prime the back of the linoleum with the adhesive. Cork tiles shall be fixed with the adhesive, which should be spread evenly with the trowel in sufficient quantity for laying only a few square meters at a time. Each tile shall be carefully placed in position to exclude air beneath the tile and also to attain proper joints between the tiles. It is advisable to use headless steel pins in conjunction with the adhesive in order to maintain contact between sub floor or screed and tile. The pins shall be driven below the surface of the tile with a hammer. If the sub floor or screed is too hard for pins, it may be necessary to weight down any lipping tiles.

7.4.1. Coving and skirting - Linoleum coving and skirting shall be formed from sheet material on the job in grades up to 3.2 mm thick. First, cove stick shall be fixed in the angle between floor and wall to give the correct contour to the cove. The linoleum, in the lengths up to 2.5 m is turned 15 cm up the wall and runs 15 cm on to the floor. It is a skilled operation and even the best craftsman may have difficulty with angles. For thicker materials, some floor layers make their coving in the workshop in 2-m lengths but each coving is purpose-made for a job. Radius of curvature of coving and skirting shall not be less than 12 .5 cm.

7.5. Finish - After laying and fixing, all traces of adhesive shall be removed from the surface as the

Work proceeds within the setting time. Care shall be taken to avoid the severing of adjacent surfaces. The surplus adhesive shall never be allowed to remain longer than 24 hours. The surface may be finished with a wax polish recommended by the manufacturer. Alternatively a coat of emulsion polish may be applied. The joints in case of cork tiles shall be lightly sanded with a fine grade abrasive paper. All traces of adhesives and dirt should be removed and the surface brushed clean. After brushing, the surface shall be wiped with a clean damp cloth to remove any further traces of dust or dirt when dry the surface may then be treated with two coats of concentrated paste wax polish as recommended by the manufacturer.

7.6. Protection - When laying and finishing are completed, the flooring shall be protected with hardboard or other sheeting till completion of the building.

8. Maintenance

8.1. General - A period of at least seven days should elapse after installation of the flooring before the start of the maintenance work. During this time the flooring shall be covered and protected from the effect of other contract work in progress in the site. Preventive measures are essential part of flooring maintenance and since dirt and dust are mainly trafficked into a building from the outside it is important to remove these materials by use of dust retaining mats at all door entrance extending to the full width of the door and of sufficient length. The practices stated below should be avoided:

(a) Incorrect use of cleaning agents,(b) Application of polishes and seals on dirty and wet surfaces, (c) Attempts to build up high thickness of polish or seal by reducing the number of applications, and (d) Excessive use of water.

8.2. Linoleum sheet or tiles - The linoleum sheet or tile surfaces shall be swept clean preferably using a mop sweeper and then washed with a cloth dampened with an aqueous solution of neutral detergent. When dry the surface shall be buffed using suitable pad and two coats of dry bright water-based emulsion polish shall be applied. The surface shall be regularly maintained by sweeping, washing with neutral detergent solution, followed by polishing with a coat of water-based emulsion polish.

8.3. If the traffic is light, the floor shall be given frequent brushing, regular polishing and an application of new polish every three to six weeks. Under moderate traffic conditions, the floor shall be given an occasional wash with a wet mop but no detergents shall be used so that the polish is not removed. Application of polish shall be done every one to three weeks.

Linoleum should not be over waxed; when this condition develops, the coatings should be cleared off with white spirit or paraffin and a light even coat of polish or two of liquid dressing applied. When the linoleum has been polished, it will remain bright for a considerable period if a dry mop is applied each day. It is this daily 'dry polish' rather than the frequent application of polish itself that maintains the glossy surface. After exceptional heavy traffic, the linoleum should be swept with a hair broom, rubbed with a mop or cloth frequently rinsed in clean water, and finally rubbed dry. Washing is seldom necessary more than once every three or four months, when only mild soaps or soaps less detergent should be used. Exceptionally heavy dirt may be removed with a cloth soaked in paraffin.

8.4. Cork tiles - The cork tiles shall be swept with a mop and then cleaned with a cloth dampened with an aqueous solution of neutral detergent and allowed drying. Apply a thin and even coating of solvent-based liquid wax. When dry the surface shall be buffed using a fibre brush and a further coat of solvent based liquid wax shall be applied. The cork tiles shall be regularly swept and dry buffed frequently, when necessary the surface shall be cleaned with solvent-based wax remover and rewaxed.

Annexure: 14-A.9

SPECIFICATIONS FOR RUBBER FLOORING MATERIALS FOR GENERAL PURPOSES

(Extract of IS: 809-1992) (Clause 14-37.3.)

1. Scope - This annexure lays down the composition, minimum requirements, workmanship and

prescribes tests  for rubber flooring material suitable  for covering floors of domestic and public  buildings, cinemas,  hospitals,  large stores,  ships,  transport  vehicles,  etc.  This standard does not cover the requirements for special types of rubber flooring used for electrical insulating purposes, conductive or antistatic flooring or rubber flooring having chemical and oil-resistant properties.

2. References - The Indian Standard listed in are necessary adjuncts to this standard.

3. Composition

The flooring shall be made from a compound of natural or synthetic rubber which may also contain reclaim rubber and suitable fillers. All colouring matter shall be of good quality, insoluble in water, resistant to alkalies and direct sunlight or artificial light.

Suitable cotton sheeting shall be used as backing.  The cotton sheeting shall be impregnated with a  high   grade  rubber compound. The Hessian used for the backing shall conform to Type II Hessian as specified in IS: 2818(Part 2)-1971. The Hessian shall be impregnated with a high grade rubber compound.

4. Workmanship

4.1. Appearance - The rubber flooring material shall be of first class workmanship, satisfactorily vulcanized, free from Sulphur bloom and objectionable odour and blisters, cracks and embedded foreign matter to the extent that it complies with the intended design. There shall be no porosity on the surface or throughout the thickness of the sheet. The surface finish of the flooring shall be either glossy or mat. The base stratum may be of any colour.  The underside of the floor covering shall be either furnished with a cloth impression or be buffed smooth. The edges and ends shall be cut true and square.

4.2. Colour - The colour of the flooring shall not be permanently affected by cleaning with water and a washing soap or by treatment with a suitable floor polish. The colour of the flooring shall not bleed into an adjacent piece of rubber.

5. Dimension

5.1. Thickness - The nominal thickness of the rubber flooring shall be one of the following:

3 mm, 4 mm, 5 mm, 6 mm

For all flooring the overall thickness when measured in the manner described in Annex B, shall not differ from the declared nominal value by more than 0-3 mm at any of the twenty measuring points.

If cloth / Hessian marking is present, the thickness of the flooring shall also be measured, using the apparatus described in Annex B, at three measuring points taken at one end of the roll. The cloth / Hessian marked side shall then be buffed down until the work just disappears. After buffing, the thickness at any one of the three measuring points shall not differ from the original un-buffed thickness at the respective point by more than 0-6 mm.

5.2. Tile sizes and squareness - Rubber flooring, when supplied in the form of tiles, shall be of any thickness (in the case of ribbed or fluted rubber flooring, the thickness refers to the thickness of the base) specified in 5.1 and of the following sizes:

200 mm x 200 mm, 300 mm x 300 mm, 500 mm x 500 mm

The length of side shall not vary from the nominal value by more than 0.15 percent when tested according to the method described in Annex C. There shall be no gap greater than 0.15 mm between any side of the tile and the arm of the jig when the tile is tested according to method described in Annex D.

5.3. Sheet width - Sheet material shall have one of the following widths: 0.9 m, 1.2 m, 1.5 m, 1.8 m, 2.0 m, and 2.1 m

The width of the sheet at any point shall not be less than the nominal value, and shall not exceed the nominal value by more than 6 mm.

The sponge-backed rubber flooring shall have a wearing surface of solid rubber at least 3 mm thick on a sponge rubber base of 3 mm thickness.

6. Performance requirements

6.1. Hardness - The hardness when tested in accordance with IS: 3400(Part 2)-1980 shall be neither less than 65 IRHD (International Rubber Hardness Degree) nor greater than 96 IRHD.

6.1.1. Tolerances on hardness -The tolerances on nominal hardness shall be as described below.

Tolerance in hardness

Nominal Hardness

IRHD

Tolerances on hardness

IRHD

65  to  76

±5

Over 76  to  86

±4

Over 86  to  96

±3

6.2. Water absorption - The rubber sheets and tiles shall not absorb water by weight more than 0.5 percent of the original weight when tested in the manner described in Annex E.

6.3. Compression set - The compression set shall not exceed 15 percent when test pieces in new condition and test pieces in new condition aged in accordance with Annex F are tested in the manner described in IS: 3400 ( Part 10 )-1977, the duration and temperature for the test being 24+0 hours and 27±1°C respectively.

The test pieces shall show no sign of cracking after the test is conducted. 6.4 Resistance to Abrasion

(Optional) When tested in accordance with IS: 3400 (Part 3)-1987 the abrasion resistance shall be as agreed between the purchaser and the supplier.

7. Packing and marking

7.1. Packing

Rubber flooring sheets shall be wrapped on spool of suitable, dimensions with the backside of the sheet in contact with the barrel of the spool.

Rubber tiles shall be wrapped in Hessian cloth and packed in wooden crates. The extreme end tiles shall be faced back to avoid damage to the surface of the tile. The dimensions of wooden boxes shall be as given below.

Size of wooden boxes containing rubber tiles

Size of rubber tiles

500 x 500 mm

300 x 300 mm

200 x 200 mm

Inside dimensions of wooden box

530 x 530 mm

330 x 330 mm

230 x 230 mm

7.2. Marking - Unless otherwise specified, each sheet, roll or tile shall be legibly and indelibly marked with the following:

(a) Indication of the source of manufacture; (b) Thickness, width and length of sheets and rolls, and thickness and size for tiles; and (c) Year of manufacture.

The flooring sheets, rolls or tiles may also be marked with the Standard Mark.

8. Sampling and criteria for conformity - Representative samples for various tests shall be drawn according to the method and scale of sampling described in Annex G. The criteria for conformity for sheets and tiles shall be in accordance with Annex G.

9. List of referred Indian standards (Clause 2)

IS. No.

Title

180-1984

Specifications for cotton sheeting (second revision)

2818 (Part 2)-1971

Specifications for Indian Hessian: Part 2 305 and 229 g/m2 at 16 percent contact regain (first revision)

3400 (Part 2)-2003

Methods of test for vulcanized rubbers: Part 2 Hardness (first revision)

3400 (Part 3)-1987

Methods of test for vulcanized rubbers: Part 3 Abrasion resistance using a rotating cylindrical drum device (first revision)

3400 (Part 10)-1977

Methods of test for vulcanized rubbers: Part 10 compression set at constant strain (first revision)

4905-1968

Methods of random sampling

10. Measurement of thickness (Clauses 5.1)

10.1. Apparatus - Carry out thickness measurements by means of a dial micrometer gauge, capable of reading to the nearest 0.02 mm, the foot of which exerts a pressure of the rubber of not less than 0.01 N/mm2 and not more than 0.021 N/mm2

10.2. Procedure - Proceed according to 10.2 as appropriate.

For sheet, materials measure the thickness at twenty scattered points along the edges and ends of the roll. For tiles, take the five tiles in the sample and for each tile measure the thickness at four scattered points.

11. Measurement of size of tiles (Clause 5.2)

11.1. Carry out the measurement with an instrument capable of measuring to accuracy of 0.02 mm. Measure each tile for length and width at three quarter points in each direction.  The average of the three measurements in each direction shall be regarded as the dimension of the tile in that direction.

12. Measurement of squareness of tiles (Clause 5.2)

12.1. Apparatus - The apparatus shall be an L-shaped metal jig compressing two arms each of length greater than the side of the tile to be tested and of approximately the same thickness, set in shape of a true right angle on a metal base plate. This plate shall be perfectly flat and free from surface defects.

12.2. Number of test piece - Five tiles shall be used for the test.

12.3. Procedure - Place the tiles against the jig, each corner in turn being inserted into the right angle

and one side of the tile held against one side of the Jig with light pressure. Measure any gap between each side of the tile and the other metal arm with a feeler gauge or microscope.

13. Determination of water absorption (Clause 6.2)

13.1. Procedure - The test specimen, 100 mm x 100 mm with clean cut edges, shall be weighed to the nearest mg (P1) and immersed in distilled water at a temperature of 27 ± 2°C for 24 hours. It shall then be removed, superficially dried with filter paper and immediately weighed (P2). The absorption of water expressed as percentage increase in weight shall be computed from the following formula:

(P2 – P1)

------------ x 100

14. Accelerated ageing (Clause 6.3)

Procedure - The test pieces shall be placed in a thermostatically controlled air oven maintained at a temperature of 70 ± 1°C. The specimens in the oven shall be stationary, free from strain, freely exposed to air on all side and not exposed to light. The total volume of specimens shall not exceed 10 percent of the air space of the oven. Air at 70 ± 1°C shall be passed into the oven at a uniform rate, which will ensure that the atmosphere in the oven is completely changed about three times in an hour. The specimen shall be aged in this manner for a continuous period of 240 hours and there after shall be kept for at least 24 hours at 27 ± 2°C in darkness before being tested.

Note: In view of the influence of exposure of samples to light in the course of accelerated ageing all such exposures should be as nearly identical as possible in tests intended for comparison. The preferable practice in all tests is to protect samples as completely as possible from the earliest moment against exposure to light.

15. Sampling and criteria for conformity of rubber flooring materials (Clause 8.1)

15.1. All the sheets or tiles of the same type and thickness and from the same batch of manufacture shall be grouped together to constitute a lot. Each lot shall be tested separately for determining its conformity or otherwise to the requirements of the specification.

15.2. Representative samples for various tests shall be drawn at random from a lot.  The number of sheets or tiles to be selected for the samples shall be in accordance with Tables 1 and 2.   For the randomness of selection of the sample the procedure as laid down in IS: 4905-1968 shall be followed.

15.3. Number of tests and criteria for conformity for sheets

All the sheets selected in accordance with 15.2 shall be inspected for appearance and dimensions.  Any sheet found to be defective for any one or more of the requirements shall be considered as defective. The lot shall be considered having satisfied the requirements of the specification for appearance and dimensions if the number of sheets found defective in the sample is less than or equal to the permissible number of defective sheets given in col. 3 of Table 1.

The lot having been found conforming to the requirements of appearance and dimensions shall be tested for hardness, water absorption and compression set test. For this purpose a number of sheets in accordance with Table 1 from among those which have been found conforming under 15.3. Shall be selected at random. Number of specimens in accordance with relevant methods of tests shall be taken out from each of the sheets and tested for all these requirements.  A sheet shall be considered as defective if the test specimens from the sheet fail to satisfy the requirements of any one or more of the tests. The lot shall be considered having satisfied the requirements. All the sheets selected shall be inspected for appearance and dimensions. Any tile found to be defective for any one or more of the requirements shall be considered as defective. The lot shall be considered having satisfied the requirements of the specification for appearance and dimensions if the number of tiles found defective in the sample is less than or equal to the permissible number of defective tiles given in Table 2 of these tests if the number of defective sheets in the sample is less than or equal to the permissible number of defective given in col. 5 of Table 1.

15.4. Number of sheets and criteria for conformity for tiles - The lot having been found conforming to the requirements of appearance and dimensions shall be tested for hardness, water absorption and compression set tests. For this purpose a number of tiles in accordance with Table 1 from among those which have been found conforming shall be selected at random. Number of specimens in accordance with relevant methods of tests shall be taken out from each of the tiles in the sample and tested for all these requirements. A tile shall be considered as defective if the test specimens from the tiles fail to satisfy the requirements of any one or more of the tests. The lot shall be considered having satisfied the requirements of these tests if the number of defective fifes in the sample is less than or equal to the permissible number of defective given in Table 2.

Table 1 Sample size and permissible number of defective for sheet

No. of sheets in the lot For appearance and dimensions For Hardness, water absorption and compression set tests
No. of sheets to be selected for the sample Permissible No. of defectives No. of sheets to be selected for the sample Permissible No. of defectives
Up to 25 5 0 2 0
26 to 50 8 0 3 0
51 to 100