WATER SUPPLY -1



WATER SUPPLY

SPECIFICATIONS FOR WATER SUPPLY WORK
13.1. General

13.1.1. Any damage caused to the building, or to electric, sanitary water supply or other installations etc. therein either due to negligence on the part of the contractor, or due to actual requirements of the work, shall be made good and the building or the installations shall be restored to its original condition by the contractor. Nothing extra shall be paid for it, except where otherwise specified.

13.1.2. All water supply installation work shall be carried out through licensed plumbers.

13.1.3. It is most important to ensure that wholesome water supply provided for drinking and culinary purposes, is in no way liable to contamination from any less satisfactory water. There shall, therefore, be no cross connection whatsoever between a pipe or fitting for conveying or containing wholesome water and a pipe or fitting for conveying or containing impure water or water liable to contamination or of uncertain quality of water which has been used for any purpose. The provision of reflux or non-return valves or closed and sealed valves shall not be construed a permissible substitute for complete absence of cross connection.

13.1.4. Where a supply of wholesome water is required as an alternative or stand by to supply of less satisfactory water or is required to be mixed with the latter, it shall be delivered only into a cistern, and by a pipe or fitting discharging into the air gap at a height above the top edge of the cistern equal to twice its nominal bore, and in no case less than 15 cm.

13.1.5. No piping shall be laid or fixed so as to pass into, through or adjoining any sewer, scour outlet or drain or any manhole connected therewith nor through any ashpit or manure-pit or any material of such nature that would be likely to cause undue deterioration of the pipe.

13.1.6. Where the laying of any pipe through fouled soil or previous material is unavoidable, the piping shall be properly protected from contact with such soil or material by being carried through an exterior cast iron tube or by some other suitable means. Any piping or fitting laid or fixed, which does not comply with the above requirements, shall be removed and re-laid in conformity with the above requirements.

13.1.7. The design of the pipe work shall be such that there is no possibility of back flow towards the source of supply from any cistern or appliance whether by siphonage or otherwise, and reflux or non-return valves shall not be relied upon to prevent such back flow.

13.1.8. All pipe work shall be so designed, laid or fixed, and maintained as to be and to remain completely watertight, thereby avoiding waste of water, damage to property and the risk of contamination of the water conveyed.

13.1.9. In designing and planning the layout of the pipe work, due attention shall be given to the maximum rate of discharge, required economy in labour and materials, protection against damage and corrosion, protection from frost, if required, and to avoidance of airlocks, noise transmission and unsightly arrangement.

13.1.10. To reduce frictional losses, piping shall be as smooth as possible inside. Methods of jointing shall be such as to avoid internal roughness and projection at the joints, whether of the jointing materials or otherwise.

13.1.11. Change in diameter and in direction shall preferably be gradual rather than abrupt to avoid undue loss of head. No bend or curve in piping shall be made so as to materially diminish or alter the cross-section.

13.1.12. Underground piping shall be laid at such a depth that it is unlikely to be damaged by frost or traffic loads and vibrations. It shall not be laid in ground liable to subsidence, but where such ground cannot be avoided, special precautions shall be taken to avoid damage to the piping. Where piping has to be laid across recently disturbed ground, the ground shall be thoroughly consolidated so as to provide a continuous and even support.

 

13.1.13. Where the service pipe is of diameter less than 50 mm the stop valves shall be of the screw-down type and shall have loose washer plates to act as non-return valves. Other stop valves in the service line may be of the gate type.

13.1.14. In flats and tenements supplied by a common service pipe a stop tap shall be fixed to control the branch each separately occupied part.  In large buildings a sufficient number of stop valves shall be fixed on branch pipes, and to control groups of ball valves and draw off taps, so as to minimize interruption of the supply during repairs, all such stop valves shall be fixed in accessible positions and properly protected from being tampered with, they may be of the gate type to minimize loss of head by friction.

13.1.15. Water for drinking or for culinary purposes as far as possible shall be on branch pipes connected directly to the service pipe.

13.1.16. Pumps shall not be allowed on the service pipe as they cause a drop of pressure on the suction side thereby affecting the supply to the adjoining properties. In cases where pumping is required, a properly protected storage tank of adequate capacity shall be provided to feed the pump.

13.1.17. Service pipes shall be so designed and constructed as to avoid air-locks, so that all piping and fittings above ground can be completely emptied of water to facilitate repairs. There shall be draining taps or draw – off taps (not underground) at the lowest points,  from which the piping shall rise continuously to draw-off taps, ball valves, cisterns, or vents (where provided at the high points).

13.1.18. Service pipes shall be designed so as to reduce the production and transmission of noise as much as possible. Appliances which create noise shall be installed as far distant as possible from the living rooms of the house. High velocity of water in piping and fittings shall be avoided. Piping shall be confined, as far as possible, to rooms where appliances are fixed, it shall have easy bends, and where quietness is particularly desired, holder bats or clamps shall be insulated from the piping by suitable pads.

13.1.19. The rising pipe to the storage cistern, if any, or any feed cistern shall be taken as directly as possible to the cistern and shall be fixed away from windows or ventilators.

All pipe work shall be planned so that the piping is accessible for inspection, replacement and repair. To avoid its being unsightly, it is usually possible to arrange it in or adjacent to cupboards, recesses, etc. provided there is sufficient space to work on the piping with the usual tools. Piping shall not be buried in walls or solid floors.  Where unavoidable, piping may be buried for short distances provided that adequate protection is given against damage and that no joints are buried.  If piping is laid in ducts or chases, these shall be roomy enough to facilitate repairs and shall be so constructed as to prevent the entry of vermin. To facilitate removal of pipe casing, floor boards covering piping shall be fixed with screws or bolts.

13.1.21. When it is necessary for a pipe to pass through a wall or floor, a sleeve shall be fixed therein for reception of the pipe and to allow freedom for expansion and contraction and other movement.  Piping laid in wood floors shall, where possible, be parallel with the joists.

13.1.22. Where storage tanks are provided to meet overall requirements of water connection of service pipe with any distributing pipe shall not be permitted except one direct connection for culinary or drinking requirements.

13.1.23. No service pipe shall be connected to any water closet or urinal. All such supplies shall be from flushing cisterns which shall be supplied form storage tank.

13.1.24. No service or supply pipe shall be connected directly to any hot-water system or to any apparatus used for heating other than through a feed cistern thereof.

13.2. Materials - The standard size of brass or gun metal fittings shall be designated by the nominal bore or the pipe outlet to which the fittings are attached. A sample of each kind of fittings shall be got approved from the engineer and all supplies made according to the approved samples. All cast fittings shall be sound and free from laps, blow holes and pitting.  Both internal and external surfaces shall be clean, smooth and free from sand etc. Burning, plugging, stopping or patching of the casting shall not be permissible. The bodies, bonnets, spindles and other parts shall be truly machined so that when assembled the parts shall be axial, parallel and cylindrical with surface smoothly finished. The area of water way of the fittings shall not be less than area of the nominal bore, chromium plating wherever specified shall be of 0.3 micron conforming to IS : 4827-83.  The chromium shall never be deposited on brass unless a heavy coating of nickel is interposed. In the case of iron a thick coat of copper shall first be applied, then one of nickel and finally the chromium. In finish and appearance the plated articles when inspected shall be free from plating defects such as blisters, pits roughness and unplated areas and shall not be stained or discoloured. Before a fitting is plated, the washer plate shall be removed from the fittings, the gland packing shall be protected from the plating solution.

13.2.1. Ball Valve (Brass) - The ball valve shall be of Brass or Gun metal as specified conforming to IS: 1703-89 (Fig. 1).  The ball valve shall be of following two classes

a)  High Pressure - Indicated by the abbreviation ‘HP’ for use on mains having pressure of 1.75 kg/sq. cm. or above. These shall remain closed at a test pressure of 13.5 kg/sq. cm.

Table .1

Sl. No.

Diameter of spherical float

Nominal size of ball valve

15 mm

20mm

25 mm

32 mm

40 mm

50 mm

1

High Pressure (mm)

127

152

203

229

254

305

2

Low Pressure   

114

127

178

203

203

254

3

Minimum weight of ball valve  including back nut, body and

piston (gms)                

283

446

823

1149

1589

1852

b)  Low pressure - Indicated by the abbreviation ‘LP’ for use on mains having a pressure up to 1.75 kg/sq. cm.  These shall remain closed at a test pressure of 3.5 kg/sq. cm. The ball valves shall be of following nominal sizes 15 mm, 20 mm, 25 mm, 32 mm, 40 mm and 50 mm. The nominal size shall correspond with the nominal bore of the inlet shanks. Polyethylene floats shall conform to IS: 9762-94  (See Table 1)

13.2.2. Bib cock and Stop cock - Brass (Fig. 2) : A bib cock (bib tap) is a draw off tap with a horizontal inlet and free outlet and a stop cock (stop tap) is a valve with a suitable means of connections for insertion in a pipe line for controlling or stopping the flow. They shall be of specified size and shall be of screw down type and shall conform to IS: 781-84. The closing device shall work by means of disc carrying a renewable non-metallic washer which shuts against water pressure on a seating at right angles to the axis of the threaded spindle which operates it. The handle shall be either crutch or butterfly type securely fixed to the spindle. Valve shall be of the loose leather seated pattern. The cocks (taps) shall open in anti-clock wise direction.

The bib cock and stop cock shall be polished bright. The minimum finished weights of bib tap (cock) and stop tap (cock) shall be as specified in Table 20.2.

In case these are required to be nickel plated, the plating shall be of the first quality with a good thick deposit of silvery whiteness capable of taking high polish which will not easily tarnish or scale.

13.2.3. Ferrules (Fig. 1) - The ferrules for connection with C. I. main shall generally conform to IS : 2692-89 It shall be of non ferrous materials with a C. I. bell mouth cover and shall be of nominal bore as specified. The ferrule shall be fitted with a screw and plug or valve capable of completely shutting off the water supply to the communication pipe, if and when required.

13.2.4. Fire hydrants (Fig. 1) - The hydrants shall be of spindle type with 65 mm outlet combined with sluice valve, unless otherwise specified. The hydrant shall conform to IS : 909-92 and shall consist of the following components :

(a)  One sluice valve class 1 type, conforming to IS: 780-84.(b)  A duck foot bend.(c)  A 65 cm male coupling instantaneous pattern; and (d)  Cast iron cap permanently secured to the duck foot-bend by means of a chain. Where the fire service requirement of coupling differs from the above, the requisite coupling shall be provided at no extra cost.

Fig.1

Fig.2

Table 2

Size (mm)

Minimum finished weight

Bib tap (Kg.)

Stop tap (Kg.)

8

0.25

0.25

10

0.30

0.35

15

0.40

0.40

20

0.75

0.75

The body and cover shall be of good quality cast iron, spindle of bronze and the nut and the valve seat of leaded tin bronze. The bodies, spindle and other parts shall be truly machined with surface smoothly finished.

13.2.5. Full way valve brass ( Fig. 2) - Full way valve is a valve with suitable means of connection for insertion in a pipe line for controlling or stopping the flow.  The valve shall be of brass fitted with a cast iron wheel and shall be of gate valve type conforming to IS : 780-84 opening full way and of the size as specified.

The valves shall be of best quality as approved by the Engineer and shall approximately have the weights specified in Table 3 with a tolerance of 5 percent.

13.2.6. Full way valve with wheel – Gun metal (Fig. 2) - These shall be of the gun metal fitted with wheel and shall be of gate valve type opening full way and of the size as specified. These shall generally conform to IS: 778-84 and their weights shall be as specified in Table 13.3.

13.2.7. Pig lead - Pig lead shall be of uniform quality; clean and free from foreign materials. It shall be of uniform softness and capable of being easily caulked or driven. It shall conform to IS: 782-78 for caulking lead in all respects.

13.2.8. Lead wool - Lead wool shall conform to IS: 782-78 in all respects. Lead wool shall consist of fine strands or plated ribbons of lead. The cross-section of the individual strands shall be flat. The dimensions in the sectional plane shall not be less than 0.13 mm and not more than 0.90 mm and the rope shall be supplied in minimum lengths of two metres and the maximum length in any one package shall be such that the package does not weigh more than 50 kg.

Table 3

mm

Flanged ends (Kg.)

Screwed ends (Kg.)

15

1.021

0.567

20

1.503

0.680

25

2.495

1.077

32

3.232

1.559

40

4.082

2.268

50

6.691

3.232

65

13.149

6.804

80

13.381

8.845

13.2.9. Non-return valve or check valve-brass (Fig. 2) - A non-return valve permits water to flow in one direction only and is provided on the ascending part of the main to check return flow. The non-return valve shall be of brass and shall be of horizontal or vertical flow type as specified. The valve shall be of quality approved by the Engineer and shall have the weights specified in Table 4 with a tolerance of 5 percent.

13.2.10. Non-Return valve or check valve – Gun Metal (Fig. 2) - Specification as described shall apply except that the non-return valve shall be of gun metal and shall generally conform to IS: 778-84

13.2.11. Pipes and Specials - Pipes and specials may be of any of the following types as specified (a)  Asbestos cement pressure pipes – IS: 1592-89(b) Cast iron centrifugally cast (spun) – IS: 1536-89(c)  Galvanized steel – IS: 1239 & IS: 4736-86 (d)  Plastic unplasticised rigid PVC – IS: 4981-84 & IS : 4985-88. In choosing the material for piping and fittings, account shall be taken of the character of the water to be conveyed through it, the nature of the ground in which the pipes are to be laid and the relative economics.

13.2.12. Pipes – Asbestos cement (Pressure Pipes)

13.2.12.1. These shall be made from a through and homogeneous mixture of ordinary portland cement conforming to IS: 269-89 and asbestos fibre free from loading and from organic fibres. The pipes shall conform to IS: 1592-89. The pipes shall be classified according to the test pressure as detailed in Table 5. The maximum working pressure, under which each pipe shall be used, shall not exceed half the test pressure for that class of pipe.

13.2.12.2. The nominal diameters of pipe shall be 50 mm, 80 mm, 100 mm, 125 mm, 150 mm, 200 mm, 250 mm, 300 mm, 450 mm, 600 mm, 900 mm and 1000 mm. The variation of the internal diameter shall not be more than 10% of the nominal internal diameter. The interior of pipes shall have a smooth finish and regular surface and regular internal diameter.  It shall be straight within tolerance limits.

13.2.12.3. Specials: Plain ended cast iron specials shall be used to suit the diameter of pipe.

Table 4

Diameters mm      

Horizontal type Kg.      

Vertical type Kg.

15

0.30

0.25

20

0.55

0.25

25

   0.90  

0.75

32

1.25

0.90

40

1.70

1.20

50

2.90

1.45

65

5.25

2.15

80

7.70

4.10

Table 5

Class

Test Pressure

Class – 5

5 kg/sq. cm (50 m head)

Class – 10

10 kg/sq. cm (100 m head)

Class – 15

15 kg/sq. cm (150 m head)

Class – 20

20 kg/sq. cm (200 m head)

Class – 25

25 kg/sq. cm (250 m head)

13.2.13. Pipes – Cast iron centrifugally cast (Spun)

13.2.13.1. The spun iron pipes shall conform to IS: 1536-89. The spun iron pipes, shall be of cast iron casted centrifugally and vary in diameters from 80 mm to 750 mm.  These shall be of class LA, class A and class B, as specified. These pipes shall be used for water pressures up to half the hydraulic test pressure as detailed in Table 6.

13.2.13.2. Specials - The specials shall conform to IS:1638-69. The hydraulic test pressure of each class shall be as detailed in Table 7.

Table 6

Types of pipes

Test pressure of Kg/sq. cm

Class LA

Class A

Class B

Spigot and socket pipe in all diameters

12

18

24

Flanged pipes up to 600 mm dia

 

18

24

Tolerances on specified dimensions shall be as prescribed in Annexure 13.A.1

Table 7

Nominal – Diameter

Test pressure in Kg/sq. cm. (metre head)

Fitting without branches or with branches not greater than half the principle diameter
Fitting with branches greater than half the principal diameter
Up to and including 300 mm
25 (250)
25 (250)
Over 300 mm and up to and including 600 mm
20 (200)
20 (200)

Over 600 mm and up to and

including 1500 mm
15 (150)
10 (100)

13.2.14. Pipes – Galvanized iron

13.2.14.1. The pipes (tubes) shall be galvanized mild steel hot finished seamless (HFS) or welded (ERW) HRIW or HFW screwed and socketed conforming to the requirements of IS : 1239-90 Part – 1 for medium grade. They shall be of the diameter (nominal bore) specified in the description of the item, the sockets shall be designated by the respective nominal bores of the pipes for which they are intended.

13.2.14.2. Galvanizing shall conform to IS : 4736-1986 - The zinc coating shall be uniform adherent, reasonably smooth and free from such imperfections as flux, ash and dross inclusions, bare batches, black spots, pimples, lumpings runs, rust stains, bulky white deposits and blisters. The pipes and sockets shall be cleanly finished, well galvanized in and out and free from cracks, surface flaws laminations and other defects. All screw threads shall be clean and well cut. The ends shall be cut cleanly and square with the axis of the tube.

Tolerances on specified dimensions shall be as prescribed in Annexure 13.A.2

13.2.14.3. The dimensions and weights of pipes and sockets and tolerances shall be as prescribed in Annexure 13.A.3

13.2.14.4. All screwed tubes and sockets shall have pipe threads conforming to the requirements of IS: 554-1985. Screwed tubes shall have taper threads while the sockets shall have parallel threads.

13.2.14.5. All tubes shall withstand a test pressure of 50 Kg/sq. cm. without showing defects of any kind.

13.2.14.6. Fittings - The fittings shall be of mild steel tubular or wrought steel fittings conforming to IS: 1239 (Part –II) or as specified. The fittings shall be designated by the respective nominal bores of the pipes for which they are intended.

13.2.15. Pipes – Plastic - The plastic pipes commercially available in the country are that of (I) low-density polyethylene (LDPE) (ii) High-density polyethylene HDPE, and (iii) Rigid unplasticised-poly-vinyl-chloride (UPVC). These pipes are corrosion resistant and light in weight, and have been found suitable for cold water services. Plastic materials perform on their own merits, and each of these plastic pipes has its own limitations and advantages for a particular application under conditions of use. Relevant Indian standard specifications have been laid down for these pipes.

13.2.15.1. Low Density Polyethylene is flexible, it is now well established that this material is used for pipes with diameter up to 63 mm, generally recommended for use in long runs e.g. for point to point conveyance of water, because of its flexibility, and fact that LDPE pipes require closer spacing of clips for horizontal and vertical runs, their use has not been found practical for installation of internal water supply system.

13.2.15.2. High Density Polyethylene is rather tougher as compared to low-density polyethylene. Pipes up to 1600 mm diameter have been produced out of this material.  In India however, HDPE pipes are available from 16 mm to 400 mm dia. Use of these pipes in small diameters for internal water supplies has not found ready acceptance because of practical problems like on-site jointing, and taking out of various connections in plumbing.  Their use in larger diameters for conveyance of water / effluents and in long run from point to point has been found very suitable and has been readily accepted by the Public Health Engineering and similar departments, in the country.

13.2.15.3. Polyethylene pipes are normally available in black colour.  These are resistant to most chemicals, except nitric acid, and very strong acids, fats, and oils and certain solvents particularly chlorinated ones. There is a phenomenon called environmental stress cracking which means that if polyethylene is stressed at normal temperatures and comes into contact with certain materials then it will crack eventually fail. The material include detergents, organic acids, esters, aldehydes, ketone, amides nitro compounds, and alcohols (but not beer).  The HDPE is worse then LDPE in this respect.

13.2.15.4. Rigid (unplasticised) PVC pipes  are widely accepted for applications such as cold water service internal / external water supplies systems, water mains, rain water system, soil waste piping system, soil waste piping system, and underground (sewage pipes) drainage piping system. Rigid PVC is three times as rigid as polyethylene it is also much stronger and will withstand much higher pressure for a given wall thickness. Joints can easily be made in rigid PVC pipes by solvent welding, and a whole range of injection moulded matching fittings and specials are available for these pipes.

Rigid PVC pipes are normally available in the following shades:-

White / cream. Light to dark grey. Black.

In general rigid PVC is resistant to most inorganic acids, alkalis and salts, as well as many organic chemicals. It is quite resistant to most effluents, salt water and plating solutions, corrosive fumes, soils and the like which lead to its applications over a wide field. The material is also perfectly safe with potable water, whether hard or soft, and in the former case it tends to retard the formation of scale. Those materials which do not attack it include concentrated oxidizing acids, esters, ketones, aromatic and chlorinated hydrocarbons, organo-nitro  compounds, organo-amino compounds, lacquer solvents and acetic anhydride. The pipes shall be reasonably round and shall be supplied in straight lengths with socketed ends. The internal and external surfaces of pipes shall be smooth & clean, free from groovings and other defects. The end shall be cleanly cut and square with the axis of the pipe. The pipe shall be designated by external diameter and shall conform to IS: 4985-88 Revised in all respects. The dimensions and tolerances of rigid PVC pipes shall be as in Annexure 13.A.4

13.2.15.5. Fittings - Fittings used shall be of the same make as that of PVC pipes, injection moulded or made in cast iron and shall conform to Indian Standard wherever available.

13.2.16. Shower rose brass - The shower rose shall be of chromium plated brass of specified diameter. It shall have uniform perforations. The inlet size shall be 15 mm or 20 mm as required.

13.2.17. Sluice valves – brass / gun metal (Fig. 2) - The sluice valves are used in a pipe line for controlling or stopping flow of water. These shall be of specified size and class and shall be of inside non-raising screw type up to 300 mm size and raising or non-raising screw type above 300 mm with either double flange or double socket ends and cap or hand wheel. These shall in all respects comply with the Indian Standard Specification IS: 780-94 for valves up to and including 300 mm size and IS : 2906-84 for valves above 300 mm size. Class I sluice valves are used for maximum working pressure of 10 Kg/sq. cm. (100 metre head) and class II sluice valve for 15 Kg/sq. cm. (150 metre head). The body, domes covers, wedge gate and stuffing box shall be of good quality cast iron, the spindle of bronze, the nut and valve seats of leaded tin bronze.  The bodies, spindles and other parts shall be truly machined with surface smoothly finished. The area of the water way of the fittings shall be not less than the area equal to the nominal bore of the pipe.  The valve shall be marked with an arrow to show the direction of turn for closing of the valve.

13.2.18. Surface box (Fig. 3&4) - This shall be of cast iron, well made and free from casting and other defects. All sharp edges shall be removed and finished smooth. The shape and dimensions for surface boxes for stop cocks, sluice valves, fire hydrants, water meters etc. shall be as specified in Fig. 3 & 4.  The C. I. surfaces boxes shall be coated with a black bituminous composition except in case of fire hydrants where the cover of the surface box shall be painted with two coats of rust resisting bright luminous yellow paint for clear visibility during night.

13.2.19. Water meter (Domestic Type)

13.2.19.1. Water meters shall be selected according to flow to be measured and not necessarily to suit a certain size of main. The following points shall govern the selection of meters:

  1. The maximum flow shall not exceed the nominal capacity of the meter.
  2. The continuous flow shall not be greater than the continuous running capacity rating.
  3. The minimum flow to be measured shall be within minimum starting flows.

13.2.19.2. Inferential water meter has the same accuracy as the semi-positive type at higher flows; it passes unfiltered water better than a semi-positive meter and is lower in cost.

13.2.19.3. Special care is necessary in selecting the most suitable meter where large rates of flow may exist for short periods. The normal working flow shall be well within the continuous running capacity specified in IS: 779, as high rates of flow over short period cause excessive wear if the meter chosen is too small for the duty.

13.2.19.4. Owing to the fine clearances in the working parts of meters, they are not suitable for measuring water containing sand or similar foreign matter, and in such cases a filter or dirt box of adequate effective area shall be fitted on the upstream side of the meter. See Fig. 2. It shall be noted that the normal strainer fitted inside a meter is not a filter and does not prevent the entry of small particles, such as sand.

13.2.19.5. Water meters and their parts, especially parts coming in continuous contact with water shall be made of materials resistant to corrosion and shall be non-toxic and non-training. Use of dissimilar metals in contact under water shall be avoided as for possible in order to minimize electrolytic corrosion.

13.2.19.6. Body - The body of water meter shall be made either from Type A or Type B materials as specified below

Type A :  The body of water meter shall be made from bronze, brass or any other corrosion resistant material e.g. Grey iron castings, black heart  malleable iron, pherodial graphite iron casting.

Type B:  The body of the water meters shall be made from suitable plastics.

NOTE:  Plastics shall have following qualities:

1)  It shall not affect the potability of water.

2) Elongation, 15 percent, Min. on a specimen of length 150 mm (for procedure of determination of elongation).

3)  Water absorption on immersion for 24 hours should not exceed 0.6 per cent by weight (for procedure of determination of water absorption).

4)  It shall be capable of withstanding temperature up to 55 degree C without undergoing deformation or softening and becoming unsatisfactorily in performance.

13.2.19.7. Registration box - Registration Box of water meters of Type A shall be made from bronze, brass, aluminium alloy or suitable plastics. Registration box of water meters of Type B shall be made from suitable plastics or aluminium alloys. The registration box of dry dial water meters shall be provided with one or two escape holes for minimizing the accumulation of condensed water.

13.2.19.8. Cap - Cap of water meters of Type A shall be made from brass, bronze, aluminium alloy or suitable plastics. The cap of water meters of Type B shall be made of plastics or aluminium alloy. Where the cap and registration box are integral, the materials for cap may be same as used for registration box. The cap shall be so designed and fixed to the registration box as to avoid entry of water and dirt. The transparent window which covers the dial shall be inserted from the inside into the

Fig. 3

cap. The protective lid shall be secured by a robust hinge or other suitable method of robust construction

Fig. 4

13.2.19.9. Locking arrangement -Provision shall also be made to lock the lid. The provision shall be such that the lock is conveniently operated from the top. Where the provision is designed for use in conjunction with padlocks, the hole provided for padlocks shall be of a diameter not less than 4 mm.

13.2.19.10. Wiper - Where so required for dry-type water meters the transparent window covering the dial shall be provided with a wiper on the inner side for wiping off condensed water.

13.2.19.11. Connecting arrangements - The meter casting shall be fitted in the pipe line by means of two conical or cylindrical nipples or tail pieces with connecting nuts which shall be provided with each meter. The nipples of water meters of Type A shall be made of the same materials as specified for body. Nipples of water meters of Type B shall be made of the same materials as specified for the body where they are integral with the body of the water meters; where they are separate, they shall be made of malleable iron, galvanized steel or suitable plastics. The nuts shall be of the same material as used for nipples. The internal diameter of the nipple where it connects the pipe line shall be equal to that corresponding to the nominal size of the meter. The threads on the connection shall conform to IS: 554-1985.  The minimum length of the threads shall be as given in Table 9.

13.2.19.12. Strainers - Water meters shall be provided with strainers. Strainers shall be of a material which is not susceptible to electrolytic corrosion. They shall be of plastics or other corrosion – resistant materials for both Type A and Type B meters. They shall be rigid, easy to remove and clean, and shall be fitted on the inlet side of the water meter. It shall be possible to remove and clean the strainer in such a way as not to permit disturbing the registration box or tampering with it.  The strainer shall have a total area of holes not less than twice the area of the nominal inlet bore of the pipe to which the meter is connected however, in the case of meters provided with internal strainer involving opening of the registration box for cleaning, an additional external strainer shall be fitted on the inlet side satisfying the above requirements.

Overall dimension of water meters shall be as specified in Table 10.

Table 9 Minimum length of thread on connection
Nominal size of meter   
Minimum length of thread
15
13
20
16
25
19
40
21
50
25

(All dimensions in millimeters) Screws & studs shall be of brass or other corrosion resistant material.

Table 10 Overall dimensions of water meters

Nominal size of Meter

Overall length  including nipples

Overall width.

(Max)

Overall

height (Max)

1

2

3

4

15

250

130

180

20

290

130

180

25

380

140

200

40

430

230

250

50

470

250

300

All dimensions are in mm.

Tolerances on the overall length shall be ± 5 mm.

13.2.19.13. Capacity on short period rating or nominal capacity - The nominal capacity of the water meters shall be as specified in Table 11. The meters shall be capable of giving minimum discharges as slated in the table without the head loss exceeding 10 m within the meters.

13.2.20. Yarn (Spun) - Spun yarn shall be of clean hemp and of good quality.  It shall be soaked in hot coal tar or bitumen and cooled before use.

13.3. SPECIFICATION FOR LAYING AND JOINTING OF PIPES AND FITTINGS

13.3.1. Unloading

13.3.1.1. The pipes shall be unloaded where they are required.

13.3.1.2. Unloading (except where mechanical handling facilities are available) – Pipes weighing up to 60 kg shall be handled by two persons by hand passing. Heavier pipes shall be unloaded from the lorry or wagon by holding them in loops, formed with ropes and sliding over planks set not steeper than 45 degree.  The planks shall be sufficiently rigid and two ropes shall always be used to roll the pipes down the planks. The ropes should be tied on the side opposite the unloading. Only one pipe shall be unloaded at a time.

Table 11 Nominal capacity of water meters

Nominal size of meter(mm)

Discharge per hour

Semi positive Type(liters)

Inferential Type (liters)

15

2000

2500

20

3400

350

25

5500

5500

40

10000

16000

50

15000

23000

13.3.1.3. Under no circumstances shall be the pipes be thrown down from the carriers or be dragged or rolled along hard surfaces. 

13.3.1.4. The pipes shall be checked for any visible damage (such as broken edges, cracking or spalling of pipe) while unloading and shall be sorted out for reclamation. Any pipe which shows sufficient damage to preclude it from being used shall be discarded.

13.3.2. Storing - The pipes and specials shall be handled with sufficient care to avoid damage to them. These shall be lined up on one side of the alignment of the trench, socket facing upgrade when line runs uphill and upstream when the line runs on level ground.

13.3.2.2. Each slack shall contain pipes of same class and size, consignment or batch number and particulars of suppliers, wherever possible, shall be marked on the stack.

13.3.2.3. Storage shall be done on firm, level and clean ground. Wedges shall be provided at the bottom layer to keep the stack stable.

13.3.3. Cutting

13.3.3.1. Cutting of pipes may be necessary when pipes are to be laid in lengths shorter than the lengths supplied, such as while replacing accessories like tees, bends, etc. at fixed position in the pipe lines.

13.3.3.2. A line shall be marked around the pipe with a chalk piece at a point where it is to be cut. The line shall be so marked that the cut is truly at right angle to the longitudinal axis of the pipe.  The pipe shall be rigidly held on two parallel rafters nailed to cross beams, taking care that the portion to be cut does not overhang and the cut mark is between the two rafters. The pipe shall be neatly cut at the chalk mark with carpenter’s saw or hacksaw having a long blade, by slowly rotating the pipe around its longitudinal axis so as to have the uncut portion on top for cutting. Cutting of the pipe at the overhang should, as far as possible, be avoided, as an overhanging and is liable to tear off due to its weight before the cutting is complete.

13.3.4. Trenches

13.3.4.1. The trenches shall be so dug that the pipes may be laid to the required alignment and at required depth.

13.3.4.2. Cover shall be measured from top of pipe to the surface of the ground.

13.3.4.3. The bed of the trench, if in soft or made up earth, shall be well watered and rammed before laying the pipes and the depressions, if any, shall be properly filled with earth and consolidated in 20 cm layers.

13.3.4.4. If the trench bottom is extremely hard or rocky or loose stony soil, the trench shall be excavated at least 150 mm below the trench grade. Rocks, stone or other hard substances from the bottom of the trench shall be removed and the trench brought back  to the required grade by filling with selected fine earth or sand (or fine moorum if fine soil or sand is not available locally) and compacted so as to provide a smooth bedding for the pipe. Where excavation requires blasting operation, it shall be ensured that no pipes have been stacked in the vicinity and completed pipe line in the vicinity has already been covered before starting of blasting operations ; this is necessary to prevent damage to the exposed pipes in the vicinity by falling stones as a result of blasting.

13.3.4.5. After the excavation of the trench is completed,  hollows shall be cut at the required position to receive the socket of the pipes and these hollows shall be of sufficient depth to ensure that the barrels of the pipes shall rest throughout their entire length on the solid ground and that sufficient spaces left for jointing the underside of the pipe joint. These socket holes shall be refilled with sand after jointing the pipe.

13.3.4.6. Roots of trees within a distance of about 0.5 meter from the side of the pipe line shall be removed or killed.

13.3.4.7. The excavated materials shall not be placed within 1 meter or half of the depth of the trench, whichever is greater, from the edge of the trench.  The materials excavated shall be separated and stacked so that in refilling they may be relaid and compacted in the same order to the satisfaction of the engineer.

13.3.4.8. The trench shall be kept free from water. Shoring and timbering shall be provided wherever required. Excavation below water table shall be done after dewatering the trenches.

13.3.4.9. Where the pipe line or drain crosses an existing road, the road crossing shall be excavated half at a time, the 2nd half being commenced after the pipes have been laid in the first half and the trench refilled.  Necessary safety measures for traffic as directed shall be adopted.  All types, water mains cables, etc., met within the course of excavation shall be carefully protected and supported. Care shall be taken not to disturb the electrical and communication cable met with during course of excavation, removal of which, if necessary, shall be arranged by the engineer.

13.3.5. Laying - The pipes shall be lowered into the trench by means of suitable pulley blocks, sheer legs chains ropes etc. In no case the pipes shall be rolled and dropped into the trench.  One end of each rope may be tied to a wooden or steel peg driven into the ground and the other end held by men which when slowly released will lower the pipe into the trench. After lowering, the pipes shall be arranged so that the spigot of one pipe is carefully centered into the socket of the next pipe, The and pushed to the full distance that it can go.  The pipe line shall be laid to the levels required. Specials shall also be laid in their proper position as stated above.

13.3.5.2. Where so directed, the pipes and specials may be laid on masonry or concrete pillars. The pipe laid on the level ground, shall be laid with socket facing the direction of flow of water.

13.3.5.3. The pipes shall rest continuously on the bottom of the trench.  The pipes shall not rest on lumps of earth or on the joints. Four metre long wooden templates may be used to check the level of the bed. Clearance of approximately 100 mm in depth and width equal to length of the collar plus 30 mm on both sides shall be provided at the joint which shall be refilled from sides after the joint is made.

13.3.5.4. In unstable soils, such as soft soils and dry lumpy soils it shall be checked whether the soils can support the pipe lines and if required suitable special foundation shall be provided.

13.3.5.5. Some clayey soils (for example black cotton soil) are drastically affected by extremes of saturation and dryness. In changing from saturated to a dry condition, these soils are subjected to extraordinary shrinkage which is usually seen in the form of wide and deep cracks in the earth surface and may result in damages to under ground structures, including pipe materials. The clay forms a tight gripping bond with the pipe, subjecting it to excessive stresses as the clay shrinks. It is recommended that in such cases an envelope of a minimum 100 mm of tamped sand shall be made around the pipe line to avoid any bonding.

13.3.5.6. In places where rock is encountered, cushion of fine earth or sand shall be provided for a depth of 150 mm by excavating extra depth of the trench, if necessary, and the pipes laid over the cushion. Where the gradient of the bed slopes is more than 30 degree it may be necessary to anchor a few pipes against sliding downwards (Fig. 5).

13.3.6. Thrust Blocks (Fig. 5) - Thrust blocks are required to transfer the resulting hydraulic thrust from the fitting of pipe on to a larger bond bearing soil section.

13.3.6.1. Thrust blocks shall be installed wherever there is a change in the direction / size of the pipe line or the pressure line diagram, or when the pipe line ends at a dead end. If necessary, thrust blocks may be constructed at valves also.

13.3.6.2. Thrust blocks shall be constructed taking into account the pipe size, water pressure, type of fitting, gravity component shell when laid on slopes and the type of soil.  The location of thrust blocks for various types fittings is given in Fig.5.

13.3.6.3. When a fitting is used to make a vertical bend, it shall be anchored to a concrete thrust block designed to have enough weight to resist the upward and outward thrust. Similarly at joints, deflected in vertical plane, it shall be ensured that the weight of the pipe, the water in the pipe and the weight of the soil over the pipe provide resistance to upward movement. If it is not enough, ballast or concrete shall be placed around the pipe in sufficient weight to counteract the thrust.

13.3.6.4. When the line is under pressure there is an outward thrust at each coupling.  Good soil, properly tamped is usually sufficient to hold pipe from side movement. However, if soft soil conditions, are encountered, it may be necessary to provide side thrust blocks of other means of anchoring. In such cases only pipe on each side of the deflected coupling shall be anchored without restricting the coupling.

13.3.6.5. Pipes on slopes need be anchored only when there is a possibility of the back fill around the pipe sloping down the hill and carrying the pipe with it. Generally for slopes up to 30 degree good well drained soil carefully tamped in layers of 100 mm under and over the pipe, right up to the top of trench will not require anchoring.

13.3.6.6. For steeper slopes, one cut of every three pipes shall be held by straps fastened to vertical supports anchored in concrete.

13.3.7. Back filling and tamping

13.3.7.1. Back filling shall follow pipe installation as closely as possible to protect pipe from falling boulders, eliminating possibility of lifting of the pipe due to flooding of open trench and shifting pipe out of line by caved in soil.

13.3.7.2. The soil under the pipe and coupling shall be solidly tamped to provide firm and continuous support for the pipe line.  Tamping shall be done either by tamping bars or by using water to consolidate the back fill materials.

13.3.7.3. The initial back fill material used shall be free of large stones and dry lumps. In stony areas the material for initial back fill can be shaved from the sides of the trenches. In bogs and marshes, the excavated material is usually little more than vegetable matter and this should not be used for bedding purposes. In such cases, gravel or crushed stone shall be hauled in.

13.3.7.4. The initial back fill shall be placed evenly in a layer of about 100 mm thick.  This shall be properly consolidated and this shall be continued till there is a cushion of at least 300 mm of cover over the pipe.

13.3.7.5. If it is desired to observe the joint or coupling during the testing of mains they shall be left exposed. Sufficient back fill shall be placed on the pipe to resist the movement due to pressure while testing.

13.3.7.6. Balance of the back fill need not be so carefully selected as the initial material. However, care shall be taken to avoid back filling with large stones which might damage the pipe when spaded into the trench.

13.3.7.7. Pipes in trenches on a slope shall have extra attention to make certain that the newly placed back fill will not become a blind drain in effect because until back fill becomes completely consolidated there is a tendency for ground or surface water to move along this looser soil resulting in a loss of support to the pipe. In such cases, the back fill shall be tamped with extra care and the tamping continued in 100 mm layers right up to the ground level.

13.3.8. Hydrostatic Tests (Fig. 6)

13.3.8.1. After a new pipe has been laid, jointed and back filled (or any valved section thereof), it shall be subjected to the following two tests:

a)  Pressure test at a pressure of at least double the maximum working pressure-pipe and joints shall be absolutely water tight under the test.

b)  Leakage test (to be conducted after the satisfactory completion of the pressure test) at a pressure to be specified by the authority for duration of two hours.

Fig. 5

13.3.8.2. Hydrostatic Tests: The portions of the line shall be tested by subjecting to pressure test as the laying progresses before the entire line is completed. In this way any error of workmanship will be found immediately and can be corrected at a minimum cost. Usually the length of the section to be tested shall not exceed 500 m.

Fig. 6

13.3.8.3. Where any section of a main is provided with concrete thrust blocks or anchorages, the pressure test shall not be made until at least five days have elapsed after the concrete is cast. If rapid hardening cement has been used in these blocks or anchorages, test shall not be made until at least two days have elapsed.

13.3.8.4. Prior to testing, enough back fill as described shall be placed over the pipe line to resist upward thrust. All thrust blocks forming part of the finished line shall have been sufficiently cured and no temporary bracing shall be used.

13.3.8.5. The open end of the section shall be sealed temporarily with an end cap having an outlet which can serve as an air relief vent or for filling the line, as may be required. The blind face of the end cap shall be properly braced during testing by screw jacks and wooden planks or steel plate as shown in Fig. 6.

13.3.8.6. The section of the line to be tested shall be filled with water manually or by a low pressure pump. Air shall be vented from all high spots in the pipe line before making the pressure strength test because entrapped air gets compressed and causes difficulty in raising the required pressure for the pressure strength test.

13.3.8.7. The test pressure shall be gradually raised at the rate of approximately one Kg./sq. cm./min.  The duration of the test if not specified shall be sufficient to make a careful check on the pipe line section.

13.4. SPECIFICATION FOR LAYING AND JOINTING OF ASBESTOS CEMENT PRESSURE PIPE (EXTERNAL WORK)

The specifications described 13.3 shall apply, as far as applicable.

13.4.1. Storing

13.4.1.1. The stack shall be in pyramid shape or the pipes laid lengthwise and crosswise in alternate layers. The pyramid stack is advisable for smaller diameter pipes, for conserving space in storing them.  The height of the stack shall not exceed 1.5 metre.

13.4.1.2. Cast iron detachable joints and fittings shall be stacked under cover and separated from the asbestos cement pipes and fittings.

13.4.1.3. Rubber rings shall be kept clean, away from grease, oil, heat and light.

13.4.2. Trenches

13.1.2.1. The width of the trench above pipe level shall be as small as possible but shall provide sufficient space necessary for jointing the pipes. The trench width shall be such as to provide a space of 300 mm on either side of the pipe.

13.4.2.2. The pipes, shall have a minimum soil cover of 750 mm, when laid under foot paths and side walks, 900 mm, when laid under roads with light traffic or under cultivated soils and 1.25 m, when laid under roads with heavy traffic when the soil has a poor bearing capacity and is subjected to heavy traffic, the pipes shall be laid on a concrete cradle. An extra trench depth of 100 mm shall be provided for each jointing pit.

13.4.3. Jointing - Before commencing jointing, the pipes, joints and ends of the pipes shall be cleaned, preferably with a hard wire brush to remove loose particles.

Cast Iron Detachable Joints (Fig. 7) - The joint shall consist of a central collar, two rubber rings, two flanges of cast iron and the required number of bolts and nuts (Fig. 7).  One flange and rubber ring shall be placed on end of the pipe already laid, and the other flange, rings and central collar shall be slipped on to the pipe to be assembled. The rubber ring shall be kept positioned at half the collar width less 2.5 mm from the end of the pipe already laid. A site gauge may be used for convenience. The other pipe shall be brought nearer leaving a gap of 5 mm between the two pipe ends. This gap will facilitate maneuvering of deflection at joints after assembly and will take care of an expansion in the pipe line. The collar shall be slided to sit square around the rubber ring to pipe no. 1 and then the rubber ring shall be rolled on pipe 2 to sit around the collar.  The flanges shall be moved on both ends to enclose rubber rings. The fastening bolts shall be inserted through the holes of the flanges and the bolts shall be tightened alternately and evenly for proper sitting of the joint.

Fig. 7

13.4.3.2. Asbestos Cement Coupling - This joint shall consist of three rubber rings and an asbestos cement coupling machined on the inside. The rubber rings shall be seated in respective grooves, after cleaning the coupling and rubber rings. The machined ends of the pipe cleaning the coupling shall be suitably lubricated which is not detrimental to rubber rings or drinking water. Then, the assembly shall be made by pushing with a crowbar (Fig. 7) or using a pipe puller. The joints shall be made by keeping the pipes in one line. Any permissible deflection at the joint shall be made after completion of the joint only. Wherever necessary, change over from cast iron pipe to asbestos cement pipes and vice versa shall be done with the help of suitable adapter shown in Fig. 7.

13.4.4. Special cast iron fittings and accessories - Normally when pipe line laid, a certain number of cast iron fittings such as tees, bends, reducers, etc., and special fittings such as air or sluice valves are required.

13.4.4.1. Laying of fittings - All cast iron fittings shall be plain ended to suit the class and diameter of pipe manufactured. Cast iron fittings are jointed by cast iron detachable joints only. Cast iron specials having flanges are jointed in the pipe line with cast iron flange adapters having one end flanged and the other plain ended.

13.4.4.2. Anchorages - It shall particularly be noted that the cast iron joints do not hold pipe end within firmly. During working or test pressure, there will be the tendency for the pipe ends or specials ends to slip out the joint, more so in case of blank end cap used for closure of pipe line and in case of degree bends and tees. In order to keep them firmly in the pipe line, anchoring of these specials are necessary against the direction of thrust. The anchorage shall consist of either concrete cast-in-situ or masonry built in cement mortar. The anchors shall be extended to the firm soil of the trench side. The shape of the anchors will depend on the kind of specials used.  They shall be spread to the full width of trench and carried vertically by the side and over the special to about 15 cm. The bearing area on sides of the trench shall be proportional to the thrust and to the bearing capacity of the sides of the trench (Fig. 5).

13.4.5. Hydrostatic Tests - The pipes shall be tested as specified in IS : 5913 in the factory and hence the purpose of field testing  is to check the quality of workmanship and  also to check whether the pipes have been damaged in transit. As such, the test pressure shall be kept as 1.5 times the actual operating pressure unless a higher test pressure is specified. However, it may be noted that the test pressure during the field test shall not exceed the valves given in Table 13.

Asbestos cement pipes always absorb a certain amount of water. Therefore, after the line is filled, it shall be allowed to stand for 24 hours, before pressure testing and the line shall be again filled.

13.4.6. Measurements

The net length of pipes as laid or fixed shall be measured in the running metres correct to a cm.  Specials shall be excluded and enumerated and paid for separately. The portion of the pipe within the collar at the joints shall not be included in the length of pipe work. Excavation refilling, shoring and timbering in trenches, masonry or concrete pillars and thrust blocks, wherever required, shall be measured and paid for separately, under relevant items of work.

The joints shall be enumerated and paid for separately.

13.4.7. Rates - The rate shall include the cost of materials and labour involved in all the operations described above except for the items measured / enumerated separately under para 13.4.6. which shall be paid for separately.

13.5. SPECIFICATIONS FOR LAYING AND JOINTING OF CAST IRON PIPES AND FITTINGS (EXTERNAL WORK)

Specifications described above 13.3 shall apply, as far as applicable.

Table 13 Test pressure for pipes

Class of pipe

Maximum field test pressure kg/sq. cm.

5

3.75

10

7.50

15

11.25

20

15.00

25

18.75

13.5.1. Trenches - The gradient is to be set out by means of boning rods and the required depth to be excavated at any point of the trench shall be regarded as directed by the Engineer.  The depth of the trench shall not be less than 1 metre measured from the top of the pipe to the surface of the ground under roads and not less than 0.75 metre elsewhere.

13.5.1.2. The width of the trench shall be the nominal diameter of the pipe plus 40 cm but it shall not be less than 55 cm in case of all kinds of soils excluding rock and not less than 1 metre in case of rock.

13.5.2. Laying - Any deviation either in plan or elevation less than 11.25 degrees shall be effected by laying the straight pipes around a flat curve of such radius that minimum thickness of lead at the face of the socket shall not be reduced below 6 mm or the opening between spigot  and socket increased beyond  12 mm at any joint. A deviation of about 2.25 degree can be effected at each joint in this way.  At the end of each day’s work the last pipe laid shall have its open ends securely closed with a wooden plug to prevent entry of water, soil, rats and any other foreign matter into the pipe.

13.5.3. Lead caulked joints with pig lead -

13.5.3.1 This type of lead caulking is generally done in providing joints in gas water and sewer lines wherever it is practicable to use cast lead caulking, but not in case of wet conditions.

13.5.3.2. The approximate depth and weights of pig lead for various diameters of C. I. pipes and specials shall be as given in Table 14.

Table 14 Lead for different sizes of pipes

Nominal size of pipe mm.

Lead per joint Kg.

Depth of lead joint mm.

1

2

3

80

1.8

45

100

2.2

45

125

2.6

45

150

3.4

50

200

5.0

50

250

6.1

50

300

7.2

55

350

8.4

55

400

9.5

55

450

14.0

55

500

15.0

60

600

19.0

60

700

22.0

60

750

25.0

60

Note:

1.  The quantity of lead given in the table are on average basis and a variation of 10 percent is permissible.

2.  Before pipes are jointed on large scale, three or four sample joints shall be made and the average consumption of lead per joint shall be got approved by the engineer.

Only required quantity of spun yarn shall be put so as to give the specified depth of lead in the joint.

13.5.4. Lead Caulked Joint with Lead Wool Yarn - This type of lead caulking is generally done when it is inconvenient or dangerous to use molten lead for joints, for example in cases such as inverted joints or in wet trenches or in exceptional cases. In such cases the joints shall be made with lead wool of yarn. Caulking with lead wool or yarn shall however be not carried without the prior permission of engineer.

13.5.4.2. The approximate weights and depths of lead wool or lead yarn required for each joint of various dia. of C. I. pipes and specials shall be as given in Table 15. Just sufficient quantity of spun yarn shall be put so as to give specified depth of lead wool.

Jointing - The spun yarn shall first be inserted and caulked into the socket as described under jointing with pig lead.  Lead wool or yarn shall then be introduced in the joint in strings not less than 6 mm thick and caulking shall be repeated with each turn of lead wool or yarn. The whole of the lead wool or yarn shall be compressed into a dense mass. The joint shall then be finally finished flush with face of the socket. 

13.5.5. Flanged joints

Cast iron pipes may be jointed by means of flanges cast on. The jointing material used between flanges of pipes shall be compressed fiber board or rubber of thickness between 1.5 mm to 3 mm. The fiber board shall be impregnated with chemically neutral mineral oil and shall have a smooth and hard surface. Its weight per m2 shall be not less than 112 gm / mm thickness.

Table 15

Diameter of pipe  Cast Iron (mm)

Weight of lead wool or   lead yarn (kg.)

Depth of lead wool or   lead yarn (mm)

80

0.80

19

100

0.90

19

125

1.25

20

150

1.60

23

200

2.05

23

250

2.95

25

300

3.50

25

350

4.65

29

400

5.70

31

450

6.70

32

500

8.30

33

600

13.00

35

700

11.80

36

750

13.60

38

800

15.40

40

900

16.80

40

Note:

An allowance of five per cent variation in the specified weights and depths is permissible.

13.5.5.2. Each bolt should be tightened a little at a time taking care to tighten diametrically opposite bolts alternatively. The practice of fully tightening the bolts one after another shall not be allowed.

13.5.5.3. Several proprietary flexible joints are available for jointing cast iron pipes and these may be used with the specific approval of the authority, however, they shall be used strictly in accordance with the manufacturer’s instructions.

13.5.5.4. For joints in small diameter cast iron piping, copper-alloy screwed unions or ferrules shall be used, and for large dia.  The joints shall be made by flanged connecting pieces.

13.5.6. Hydrostatic - The procedure for testing for leakage under pressure shall be as described in Annexure 13-A.5. The joints of pipes and specials have to be repaired till the leakage in the portion under test is within the specified limit indicated in Annexure 13-A.5

13.5.7. Measurements

13.5.7.1. The net length of pipes as laid or fixed, shall be measured in the running metres correct to a cm specials shall be excluded and enumerated and paid for separately.  The portion of the pipe within the collar at the joints shall not be included in the length of pipe work.

13.5.7.2. Excavation, refilling, shoring and timbering in trenches masonry or concrete pillars and thrust blocks, wherever required, shall be measured and paid for separately, under relevant items of work.

13.5.7.3. Lead caulked joints shall be measured and paid for separately.

13.5.8. Rate - The rate shall include the cost of materials and labour involved in all the operations described above except for the items measured / enumerated separately, which shall be paid for separately.

13.6. SPECIFICATIONS FOR LAYING AND JOINTING OF G. I. PIPES (EXTERNAL WORK)

The specifications described in 13.3 shall apply, as far as possible.

13.6.1. Trenches - The galvanized iron pipes and fittings shall be laid in trenches. The widths and depths of the trenches for different diameters of the pipes shall be as in Table 16.

Table 16

Dia of pipe (mm)

Width of trench (cm)

Depth of trench (cm)

15 to 50

30

60

65 to 100

45

75

 

At joints the trench width shall be widened where necessary. The work of excavation and refilling shall be done true to line and gradient in accordance with general specifications for earth work in trenches. When excavation is done in rock, it shall be cut deep enough to permit the pipes to be laid on a cushion of sand minimum 7.5 cm deep.

13.6.2. Cutting and Threading - Where the pipes have to be cut or re-threaded the ends shall be carefully filed out so that no obstruction to bore is offered.  The end of the pipes shall then be carefully threaded conforming to the requirements of IS: 554-1985 with pipe dies and tapes in such a manner as will not result in slackness of joints when the two pieces are screwed together.  The taps and dies shall be used only for straightening screw threads which have become bent or damaged and shall not procedure may not result in a water tight joint. The screw threads of pipes and fitting shall be protected from damage until they are fitted.

13.6.3. Jointing - The pipes shall be cleaned and cleared of all foreign matter before being laid. In jointing the pipes, the inside of the socket and the screwed end of the pipes shall be oiled and rubbed over with white lead and a few turns of spun yarn wrapped round the screwed end of the pipe. The end shall then be screwed in the socket, Tee etc. with the pipe wrench.  Care shall be taken that all pipes and fittings are properly jointed so as to make the joints completely water tight and pipes are kept at all times free from dust and dirt during fixing. Burr from the joints shall be removed after screwing. After laying, the open ends of the pipes shall be temporarily plugged to prevent access of water, soil or any other foreign matter.

13.6.4. Thrust Blocks (Fig. 5) - In case of bigger diameter pipes where the pressure is very high, thrust blocks of cement concrete 1:2:4 (1 cement : 2 coarse sand : 4 graded stone aggregate of 20 mm nominal size) of adequate size and shape shall be provided on all bends to transmit the hydraulic thrust to the ground, spreading it over a sufficient areas depending upon the type of soil met with.

13.6.5. Painting- The pipes shall be painted with two coats of anticorrosive bitumastic paint of approved quality.

13.6.6. Testing of Joints - The pipes and fittings after they are laid and jointed shall be tested to hydraulic pressure of 6 Kg/sq. cm. (60 meter). The pipes shall be slowly and carefully charged with water allowing all air to escape and avoiding all shock or water hammer. The draw off taps and stopcocks shall then be closed and specified hydraulic pressure shall be applied gradually.  Pressure gauge must be accurate and preferably should have been re-calibrated before the test. The test pump having been stopped, the test pressure should be maintained without loss for at least half an hour. The pipes and fittings shall be tested in sections as the work of laying proceeds, having the joints exposed for inspection during the testing. Pipes or fittings which are found leaking shall be replaced and joints found leaking shall be redone, without extra payment.

13.6.7. Trench Filling - The pipes shall be laid on a layer of 7.5 cm sand and filled up to 15 cm above the pipes. The remaining portion of the trench shall then be filled with excavated earth as described. The surplus earth shall be disposed off as directed.

13.6.8. Measurements - The lengths shall be measured in running metre correct to a cm for the finished work, which shall include G. I. pipe and G. I. fittings such as bends, tees, elbows reducers, crosses, plugs, sockets, nipples and nuts, but exclude brass of gun metal taps (cocks), valves, lead connection pipes and shower rose. All pipes and fittings shall be classified according to their diameters, method of jointing and fixing substance, quality and finish.  In case of fittings of an equal bore, the pipe shall be described as including all cuttings and wastage. In case of fittings of unequal bore, the largest bore shall be measured.  Digging and refilling of trenches shall either be measured separately as specified in the appropriate clauses of excavation and earth work or clubbed with main item.

13.6.9. Rate - The rate shall included then cost of labour and materials involved in all the operations described above. The rate shall not include excavation in trenches, painting of pipes and sand filling all round the pipes, unless otherwise specified.

13.7. SPECIFICATIONS FOR LAYING AND JOINTING UNPLASTICISED PVC PIPES (EXTERNAL WORK)

13.7.0. Handling and storage - Unplasticized PVC pipes are light in weight material. Reasonable care shall be taken in handling and storage of these to prevent damages. On no account the pipes shall be dragged along the ground. Pipes shall be given adequate support at all times. They shall not be stacked in large piles, especially under warm temperature conditions as the bottom pipes may distort, thus giving rise to difficulty in pipe alignment and jointing.

For temporary storage in the field, where racks are not provided care shall be taken that the ground is level and free from loose stones. Pipes stored thus shall not exceed three layers and shall be so stacked as to prevent movement, the pipes shall preferably be stored under shade.

For satisfactory service performance of plastic pipes under conditions of use, the following points must be kept in view while undertaking installation of plastic piping system:

(a)  The plastic materials are ‘thermoplastic’ in nature, and must not be used in contact with hot surfaces (or hot water); (b)  They must be supported at regular intervals for above ground installation ;

(c)  Allowance must be made, during installation for their expansion, particularly by using loose clips / clamps ; (d)  A range of specials, and matching fittings must be identified and their manufacturers / suppliers listed.

Rigid PVC pipes up to 600 mm dia have been produced. However, in India these are available from 16 mm to 315 mm. In these specifications only the use of rigid (unplasticized) PVC pipes for cold water supplies is covered.

13.7.1. Trenches - The trench bottom shall be carefully examined for the presence of hard objects such as flints, rock projections or tree roots etc. pipes shall be bedded in sand or soft soil free from rock and gravel. Back fill 15 cm above the pipe shall also be of fine sand or soft soil.  Pipes shall not be painted. The width of trench shall be not less than outside diameter of pipe  plus 30 cm in case of gravel soils. Pipes shall be laid at least 90 cms below the ground level (measured from surface of the ground to the top of the pipe).

13.7.2. Jointing

Solved Welded Joints (Fig. 9)

Non heat application method- In this method, instead of forming a socket on one pipe and an injection moulded socket fitting or coupler is used, with a provision to take in the pipes at both ends.

The solvent cements are applied on the surfaces to be jointed and the joint is made at ambient temperature.  Injection moulded fittings only shall be used in preference to fabricated fittings, only solvent recommended by the manufacturers of the pipes shall be used and full load on the joints applied only after 24 hours. The pipe shall be cut perpendicular to the axis of the pipe length with a metal cutting saw or an ordinary hand saw with small teeth.  Pipe ends have to be beveled slightly with a beveling tool (Reamer) at an angle of about 30 degree. The total length of insertion socket (injection moulded socket or couplet) shall be marked on the pipe and checked how far the pipe end could be inserted into the fitting socket. Attempt shall be made to push the pipe to the marked distance, if not possible it shall at least be pushed for 2/3 of this distance.

Fig.9

Dust, oil, water grease etc, shall be wiped cut with a dry cloth from the surface.  Further the grease should be thoroughly removed with a suitable solvent, such as methylene chloride or as an alternative the outside surface of the pipe and the inside of the fitting may be roughened with emery paper.

Generous coatings of solvent cement shall be evenly applied on the inside of the fitting all round the circumference for the full length of insertion and on the outside of the pipe end up to the marked line pipe shall be pushed into the fitting socket and held for 1 or 2 minutes as otherwise the pipe may come out of the fitting due to the slippery quality of cement and the tapering inside bore of the fitting. The surplus cement on the pipe surfaces shall be wiped out.  If the solvent cement has dried up too much or the tapering of the socket is too steep, jointing will not be proper and pipe will come out of the fitting.

In summer months joints shall be made preferable early in the morning or in the evening when it is cooler. This will prevent joint form pulling apart when the pipe cools off at night. Heat application method for jointing shall not be allowed.

Flanged joints - For jointing PVC pipes particularly of larger sizes to valves and vessels and larger size metal pipes where the tensile strength is required the joint is made by the compression of a gasket or ring seal in the face of C. I. flange. Flanges solvent welded to the PVC pipes shall be supplied by the manufacturers.

Rubber ring joints - Rubber ring joints can provide a water tight seal but do not resist pull.  As such these may be used only as repairs collar and for jointing pipes larger than 110 mm. Such joints may be provided on pipes which are buried in the ground and supported throughout on bedding so that they are not subject to movement and longitudinal pull. The material of rubber ring shall conform to IS: 5382-1985 where aggressive soil are met with, synthetic rubbers perform better for jointing. The rings shall be housed in a groove formed in plastic or metallic housing.  The rubber is compressed and makes a seal between the pipe and the housing. The ring shape and the method of compressing the ring vary considerably in different types of joints.  Most joints often require the application of lubricating paste which shall be procured from the manufacturer of PVC pipes.  Rubber rings shall be supplied by the manufacturers.

The rubber ring joints can be either of:

(1) With spigot and socket, or (2) With separate collar pieces having two rubber rings, one at either end.

13.7.3.Crossing Road or Drain (Fig. 10)- Where the pipe line crosses a road or a drain, it shall be through C. I. or RCC pipe.

13.7.4. Supports for Valve and Hydrant - Valve and hydrant tees shall be supported as shown in Fig. 11 so that the torque applied in operating a valve is not transmitted to the pipe line.

13.7.5. Inspection and Testing - Solvent welded pipe shall not be pressure tested until at least 24 hours after the last solvent cemented joint has been done.

All control valves shall be positioned open for the duration of the test and open and closed with water tight fittings. The testing pressure on completion of the work shall not be less than one and a half times the working pressure of the pipes as indicated in Table 22.

Pressure shall be applied either by hand pump or power driven pump. Pressure gauges shall be correctly positioned and closely observed to ensure that at no time are the test pressure exceeded.  The systems shall be slowly and carefully filled with water to avoid surge pressure or water hammer. Air vents shall be open at all high points so that air may be expelled from the system during filling.

When the system has been fully charged with water and air displaced from the line air vent shall be closed and the line initially inspected for seepage at joints and firmness of supports under load. Pressure may then be applied until the required test pressure is reached.

Without any additional requirements of make-up-water the test pressure should not fall more than 0.2 kg/sq. cm. at the end of one hour test duration.

13.7.6. Measurements - The length shall be measured in running metre correct to a cm for the finished work which shall include PVC fittings such as bends, tees, elbows, reducer, crosses, plugs, sockets, nipples and nuts, but exclude taps, valves, etc. All pipes and fittings shall be classified according to that outside diameters and pressure ratings. Fittings of unequal outside diameter shall be measured along with the larger diameter pipe.

13.7.7. Rate - The rate shall include the cost of labour and material in all the operation described above except excavation in trenches, sand filling all round the pipes, metal pipe used for encasing PVC pipe and anchor blocks, unless otherwise specified.

13.8. SPECIFICATIONS FOR LAYING AND JOINTING G. I. PIPES (INTERNAL WORK)

13.8.1. For internal work the galvanized iron pipes and fittings shall run on the surface of the walls or ceiling (not in chase) unless otherwise specified. The fixing shall be done by means of standard pattern holder bat clamps, keeping the pipes about 1.5 cm clear of the wall. When it is found necessary to conceal the pipes, chasing may be adopted or pipes fixed in the ducts or recess etc., provided there is sufficient space to work on the pipes with the usual tools. The pipes shall not ordinarily be buried in walls or solid floors.  Where unavoidable, pipes may be buried for short distances provided adequate protection is given against damage and where so required joints are not buried. Where directed by the engineer, a M. S. tube sleeve shall be fixed at a place the pipe is passing through a wall or floor for reception of the pipe and to allow freedom for expansion and contraction and other movements. In case the pipe is embedded in walls or floors it should be painted with anticorrosive bitumastic paints of approved quality. The pipe shall not come in contact with lime mortar or lime concrete as the pipe is affected by time. Under the floors the pipes shall be laid in layer of sand filling as done under concrete floors.

All pipes and fittings shall be fixed truly vertical and horizontal unless unavoidable. The pipes shall be fixed to walls with standard pattern holder bat clamps of required shape and size so as to fit tightly on the pipes when tightened with screwed bolts, these clamps shall be embedded in brick work in

Fig. 10

cement mortar 1:3 (1 cement : 3 coarse sand), and shall be spaced at regular intervals in straight lengths as shown in Table 17. The clamps shall be fixed at shorter lengths near the fittings as directed by the engineer.

For G. I. pipes 15 mm diameter, the holes in the walls and floors shall be made by drilling with chisel or jumper and not by dismantling the brick work or concrete. However, for bigger dimension pipes the holes shall be carefully made of the smallest size as directed by the Engineer. After fixing the pipes the holes shall be made good with cement mortar 1:3 (1 cement : 3 coarse sand) and properly finished to match the adjacent surface.

Table 17

Dia. of Pipe (mm)

Horizontal length (M)

Vertical length (M)

15

2

2.5

20

2.5

3

25

2.5

3

32

2.5

3

40

3

3.5

50

3

3.5

65

3.5

5

80

3.5

5

Unions will be provided to facilitate connections additions and alterations as well as for maintenance and for change of pipes.  The locations where unions are to be provided will be decided with prior written approval of the engineer.

13.8.2. Measurements - The lengths shall be measured in running metre correct to a cm for the finished work, which shall include G. I. pipe and G. I. fittings such as bends, tees elbows, reducers, crosses, plugs, sockets, nipples and nuts, but exclude brass or gun metal taps (cocks), valves, unions, lead connection pipes and shower rose. All pipes and fittings shall be classified according to their diameters, method of jointing and fixing substance, quality and finish. In case of fittings of an equal bore the pipe shall be described as including all cuttings and waste. In case of fittings of unequal bore, the largest bore shall be measured. Pipes laid in trenches (or without supports) and pipes fixed to walls, ceilings, etc. with supports shall be measured separately.

13.8.3. Rate - The rate shall include the cost of labour and material involved in all the operations described above. The rate shall include the cost of cutting holes in walls and floors and making good the same.  This shall not however, include concealed pipe work in which case cutting of chase and making good shall be paid separately.  It shall not include painting of pipes and providing sleeves, unless specified otherwise. It will also not include union which shall be paid for separately.

13.9. SPECIFICATION FOR LAYING AND JOINTING PVC PIPES  (INTERNAL WORK)

13.9.1. Clamping - The pipes shall be laid and clamped to wooden plugs fixed above the surface of the wall, as shown in Fig. 8.  Alternatively plastic clamps of suitable designs, whenever manufactured shall be preferred. Provision shall be made for the effect of thermal movement by not gripping or districting the pipe at supports between the anchors for suspended pipes. The supports shall allow the repeated longitudinal temperature movement to take place without abrasion. Line or point contact with the pipe shall be avoided. Heavy components such as metal valves shall be individually supported.

13.9.2. Supports - PVC pipes require supports at close interval. Recommended support spacings for unplasticised PVC pipes are given in Table 18. This spacing may be increased by 50% for vertical runs support.

Table 18

Pipe Dia. (mm)

Support spacing (mm)

20

700

25

750

32

825

40

975

50

975

It is essential that PVC pipes shall be aligned properly before fixing them on the wooden plugs with clamps. Even if the wooden plugs are fixed using a plumb line, PVC pipe shall also be checked for its alignment before clamping. The pipe line will be wavy if the clamps are not fixed keeping the pipe plumb.

13.9.3. Connection to a Water Tap - Connection to the water tap shall be made by means of a G. I. adopter as shown in the Fig. 8. G. I. adopter shall preferably be supplied by the same manufacturer as that of PVC pipe. In any threaded coupling between PVC and G. I. is preferable that PVC is fitted inside the G. I. fitting. If however greater projection is desired, same shall be achieved by joining a short piece of a G. I. pipe (Nipple) as shown in Fig. 8.

13.9.4. Connection to a shower Rose - Shower Rose connection shall be of G. I. pipes as shown in Fig. 8.

Fig.8

13.9.5. Connection from masonry / concrete water tank - Solvent cement shall be coated on the section of the pipe to be embedded in concrete. Fine dry sand and cement mixture shall be sprinkled uniformly around the pipe. This shall give a rough surface which can be safely embedded in concrete, water proofing cement shall be used to close the gap properly.

13.9.6. Measurements -The length shall be measured in running metre correct to a cm for the finished work which shall include PVC fittings such as bends, tees, elbows, reducer, crosses plugs, sockets, nipples and nuts, but exclude, taps, valves, etc. All pipes and fittings shall be classified according to their outside diameters shall be measured along with the larger diameter pipe.

13.9.7. Rate - The rate shall include the cost of labour and material in all the operation described above, except metal pipe used for encasing PVC pipe and anchor blocks, unless otherwise specified.

13.10. SPECIFICATIONS FOR MAKING CONNECTION OF G. I. DISTRIBUTION BRANCH  WITH G. I. MAIN

13.10.1. Preliminary Work - A pit of suitable dimensions shall be dug at the point where the connection is to be made with the main and earth removed up to 15 cm below the main. The flow of water in the water main shall also be disconnected by closing the sluice or wheel axis valves on the mains.

13.10.2. Making Connection - For cutting and jointing 20.6.2 and 20.6.3 shall apply. The G. I. main shall first be cut. Water if any collected in the pit shall be bailed out and, ends of the G. I. pipes threaded. The connection of distribution pipe shall then be made after fixing G. I. tee of the required size to the G. I. main and fittings such as Jam nut, G. I. socket connecting piece etc.

13.10.3. Testing of Joints - After laying and jointing, the pipes and fittings shall be inspected under working condition of pressure and flow. Any joint found leaking shall be redone and all leaking pipes removed and replaced without extra payment.  The pipes & fittings after they are laid shall be tested to hydraulic pressure of 6 kg/sq. cm. (60 m). The pipes shall be slowly and carefully charged with water allowing all air to escape and avoiding all shock of water hammer. The draw of laps and stop cocks shall then be closed and specified hydraulic pressure shall be applied gradually.  Pressure gauge must be accurate and preferably should have been re-calibrated before the test. The test pump having been stopped, the test pressure should be maintained without loss for at least half an hour. The pipes and fittings shall be tested in sections as the work of laying proceeds, having the joints exposed for inspection during the testing.

13.10.4. Finishing - The portion of the pipe in the pit shall be painted with bitumastic paint and encased with sand 15 cm all round. The pit shall be filled with earth in level with the original ground surface watered, rammed and the area dressed.

13.10.5. Measurements: The work of making connections shall be enumerated.

13.10.6. Rate - The rate shall include the cost of labour and materials involved in all the operations described above.

13.11. SPEICIFICATIONS FOR PVC PIPES SERVICE CONNECTION (FIG. 10)

13.11.1. Either metal or PVC saddles, as specified, shall be used for the off take of service connections from larger bore pipes (50 mm diameter and above). The saddle consists of two half round sections or held round the pipe by wedge grips. A seal is formed between the saddle and the pipe and the under surface of the upper section. The service connection is taken from a boss on the upper section.

Conventional equipment for tapping under pressure may be used with these service connections using a special trapanning cutter to pierce the pipe wall. Ferrules shall not be screwed directly into pipes without the introduction of saddle piece. A typical illustration of a ferrule connection is shown in Fig. 10.

13.11.2. Measurements - Connections shall be enumerated.

13.11.3. Rate -The rate shall include the cost of labour and materials involved in all the operations described above.

13.12. SPECIFICATIONS FOR P. V. C. PIPE – REPAIRS

While temporary or emergency repairs may be made to the damaged pipes, permanent repairs should be made by replacement of the damaged section.  In case of damage by external blows, the extent of the drainage may be greater on the inner surface.

Some times, pipes are damaged accidentally due to trenching operation in street repairs. Shell spirit or chip out occurs in the wall of the pipe, a short piece of pipe of sufficient length to cover the damaged portion of the pipe is cut. The sleeve is cut longitudinally and heated sufficiently to soften it so that it may be slipped over the damaged pipe.

13.12.1. Measurements - Repairs shall be enumerated.

13.12.2. Rate - Rate shall include the cost of all materials and labour involved in all the operations described above.

P.V.C. PIPING

Fig 10

13.13. SPECIFICATIONS FOR FIXING BRASS AND GUN METAL WATER FITTINGS

13.13.1. The fitting shall be fully examined and cleared of all foreign matter before being fixed. The fitting shall be fitted in the pipe line in a workman like manner. The joints between fittings and pipes shall be leak-proof when tested to a pressure of 17.5 kg/sq. cm.  The defective fittings and joints shall be replaced or redone.

13.13.2. Measurements - Fittings shall be enumerated

13.13.2. Rate - The rate shall include the cost of all the material and labour involved in all the operation described above.

13.14. SPECIFICATIONS FOR FIXING FERRULES

13.14.1. For fixing ferrule the empty main shall be drilled and tapped at 45 degree to the vertical and the ferrule screwed in. The ferrule must be so fitted that no portion of the shank shall be left projecting within the main into which it is fitted.

13.14.2. Measurements - Ferrule shall be enumerated.

13.14.3. Rate - The rate shall include the cost of all materials and labour involved in fixing the ferrule.

13.15. SPECIFICATIONS FOR INSTALLATION OF FIRE HYDRANT

13.15.1. The hydrant shall be fully examined and cleared of all foreign matter before being fixed. The fixing shall be done on the water main which shall be of minimum 80 mm dia.  The flanged end of the hydrant shall be fixed to the flanged outlet of a tee in the water  main by means of bolts, nuts and 3 mm rubber insertion or chemically treated compressed fibre board 1.5 mm minimum thickness and of weight not less than 0.183 gm. per sq. cm.  This can also be fixed by means of flanged tail piece which also be fixed by means of flanged tail piece which may be connected to the water main by C. I. specials.

13.15.2. Measurements - Fire hydrant shall be enumerated.

13.15.3. Rate - The rate shall include the cost of materials and labour involved in all the operations described above against relevant item of work.

13.16. INSTALLATION OF WATER METER AND STOP COCK (FIG. 2)

13.16.1. The G. I. line shall be cut to the required length at the position where the meter and stop  cock are required to be fixed.  The ends at the pipe shall then be threaded. The meter of connecting pipes, G. I. jam nut and socket etc. The stop cock shall be fixed near the inlet of the water meter. The paper disc inserted in the nipples of the meter shall be removed and the meter installed exactly horizontal or vertical in the flow line in the direction shown by the arrow cast on the body of the meter.  Care shall be taken that the factory seal of the meter is not disturbed. Wherever the meter shall be fixed to a newly fitted pipe line, the pipe line shall have to be completely washed before fitting the meter. For this purpose a piece of pipe equal to the length of the meter shall be fitted in the proposed position of the meter in the new pipe line. The water shall be allowed to flow completely to wash the pipe line and then the meter installed as described above by replacing the connecting piece.

13.16.2. Testing of Joints: Testing of joints shall be done as described.

13.16.3. Measurements - The work of fixing meters and stop cocks shall be counted in numbers separately according to the diameters.

13.16.4. Rate - The rate shall include the cost of labour and materials involved in all the operations described above excluding the cost of stock cock and water meter.

13.17. SPECIFICATIONS FOR FIXING SURFACE BOX (FIG. 4)

13.17.1. The C. I. surface box shall be fixed on the top of masonry chamber in plain or reinforced cement concrete 1:2:4 (1 cement : 2 coarse sand : 4 graded stone aggregate 20 mm nominal size) as the case may be.

13.17.2. Measurements - Masonry chambers shall be enumerated under the relevant items.

13.17.3. Rate - The rate shall include the cost of materials and labour involved in all the operations described above, except the excavation in saturated soil, soft or decomposed and hard rock if met with. The difference of cost, between ordinary soil and saturated soil or soft or decomposed or hard rock as the case may be, shall be paid for separately.

Fig. 11

13.18. SPECIFICATIONS FOR CONSTRUCTING R. C. C. POST FOR HYDRANT (FIG. 11)

13.18.1. The R. C. C. post for a hydrant shall be of the size 25 x 25 cm at the bottom and 15 x 15 cm at the top. A pipe of specified size shall be provided during casting in the centre of the post.  The post shall be of 170 cm height, out of which 60 cm shall be kept below ground level.

13.18.2. Earth Work- The excavated earth shall be disposed off as directed by the Engineer.

13.18.3. Reinforced Cement Concrete Work - The post shall be made of cement concrete 1:2:4 (1 cement: 2 coarse sand : 4 graded stone aggregate 12.5 mm nominal size) and reinforced with 4 Nos. 10 mm dia. bars at corners.  6 Nos. square stirrups of 6 mm diameter bars shall be provided for

keeping the vertical reinforcement in position.

13.18.4. Finishing - The R. C. C. post shall be plastered with 6 mm thick cement plaster 1:4 (1 cement : 4 fine sand) on all the exposed surfaces and up to a depth of 15 cm below ground level. The plastered surface shall be finished with a floating coat of neat cement.

13.18.5. Measurements - The R. C. C. posts shall be enumerated.

13.18.6. Rate - The rate shall include the cost of labour and materials required for all the operations described above including providing and embedding of the pipe in the post.

13.19. SPECIFICATIONS FOF CONSTRUCTING MASONRY PILLAR FOR HYDRANT (FIG. 11)

13.19.1 The section of the pillar shall be one and half brick square or one brick square, as specified. The height of the pillar above ground shall be 110 cm.

13.19.2. Earth work- The excavated earth shall be disposed off as directed by the Engineer.

13.19.3. Concrete work - Foundation concrete shall consist of 15 mm thick cement concrete 1:5:10 (1 cement : 5 fine sand : 10 graded stone aggregate 40 mm nominal size).

13.19.4. Brick work - The masonry shall be with bricks of class designation 75 in cement mortar, 1:4 (1 cement : 4 fine sand).  The brick masonry shall be kept up to a height of 100 cm above ground level.  The hydrant pipe shall pass through the post or shall be fixed to pillar with G. I. holder bat clamps as directed by the Engineer.

13.19.5. Finishing - The pillar masonry shall be plastered with 12 mm cement plaster 1:4 (1 cement : 4 coarse sand) finished with a floating coat of neat cement. The top of the masonry pillar shall have 10 mm thick cement concrete 1:2:4 (1 cement : 2 coarse sand : 4 graded stone aggregate 12.5 mm nominal size) copying with edges rounded off. The concrete of the coping shall be rendered smooth with neat cement.

13.19.6. Measurements - Hydrant pillars shall be enumerated.

13.19.7. Rate - The rate shall include the cost of labour and materials required for all the operations described above except providing and fixing of pipe which shall be paid separately.

13.20. SPECIFICATIONS FOR CONSTRUCTION MASONRY PLATFORM FOR STAND POST (FIG 11)

13.20.1. The internal dimension of the platform shall be 120 x 120 cm or 90 x 90 cm as specified.

13.20.2. Earth Work - Earth work shall be done true to dimensions as shown in the drawing. The excavated earth shall be disposed off as directed by the Engineer.

13.20.3. Concrete Work - Foundation for the platform shall consist of 10 cm thick cement concrete 1:5:10 (1 cement : 5 fine sand : 10 graded stone aggregate 40 mm nominal size).

13.20.4. Kerbing - The kerbing for the platform shall be of half brick work with bricks of class designation 75 in cement mortar 1:4 (1 cement : 4 fine sand).  The kerb shall be plastered on top and sides with 12 mm thick cement plaster 1:4 (1 cement : 4 coarse sand) finished with a floating coat of neat cement.  The junctions and corners of the kerbing and the floor shall be rounded off.

13.20.5. Flooring - Flooring shall consist of 40 mm thick cement concrete 1:2:4 (1 cement : 2 coarse sand : 4 graded stone aggregate 20 mm nominal size) which shall be finished with a floating coat of neat cement.  The floor shall be given proper slopes as directed by the Engineer.

13.20.6. Measurements - Platforms for stand posts shall be enumerated.

13.20.7. Rate - The rate shall include the cost of labour and materials required for all the operations described above.

13.21. SPECIFICATIONS FOR CONSTRUCTING MASONRY WATER STORAGE TANKS ON TERRACES (FIG. 12)

Fig. 12

13.21.1. Tank shall be located nearest to the fittings for which water is to be supplied so that long horizontal length of G. I. delivery pipe is avoided. It should not be visible, as far as possible, from the main road and compound of the buildings. The over flow pipe shall discharge at a convenient and visible point so that it does not damage the building and does not prove a nuisance, should the tank go out of order. A bottom clearance of not less than 30 cm shall be provided to permit easy clearance of the terrace below the tank.

13.21.2. The suggestive sizes of tanks, with free board of 15 cm are given in Table 19.

Table 19

Net Capacity (Liters)

Internal size (L X B X h) (cm)

300 litres

70 x 70 x 75

600 litres

90 x 90 x 90

900 litres

105 x 105 x 90

1200 litres

120 x 120 x 100

1400 litres

120 x 120 x 115

1600 litres

120 x 120 x 120

1800 litres

130 x 130 x 125

Where more than one tank is to be provided at one place, a larger tank of combined net capacity may be built with suitable internal partitions to achieve an economical design.

13.21.3. All the fittings except float valve and mosquito proof coupling shall be fixed during construction of slab and side walls as the work proceeds and no subsequent piercing of tank slab and walls shall be permitted.

13.21.4. Bottom Slab - The bottom slab of the tank shall be of reinforced cement concrete 1:1:5:3 (1 cement : 1:5 coarse sand : 3 stone aggregate 20 mm nominal size).  This shall be supported on structurally adequate supports of brick masonry walls / reinforced cement concrete beams / or rolled steel sections and shall be given a mild slope towards scour pipe outlet. The slab thickness shall be 10 cm for sizes given above, reinforcement details shall be as given in Fig. 12. For sizes other than those given above, or a combination of tanks, the structural details shall be supplied by the engineer. When the slab is supported on brick masonry walls, the top of the walls shall be provided bearing plaster as for suspended floors. When the slab is supported on R. C. C. beam this can be either integral or simply supported as the situation may warrant. A slab with simply supported conditions on the beam is preferable. If it is to be simply supported, the beam top shall be rendered with a coat of neat cement and provided with a thick coat of lime wash.

13.21.5. Walls - The walls shall be of brick masonry in cement mortar 1:3 (1 cement  : 3 coarse sand) of class 75 of bricks. First coarse of brick masonry shall be laid immediately after concreting of the base slab, i.e. when the concrete is still green. The remaining masonry shall be raised and complete within a week of laying the slab.

13.21.6. Fittings

Scour pipe - A 40 mm dia G. I. pipe, joined with 40 mm G. I. ‘T’ to prevent slipping, shall be embedded inside wall to serve as scour pipe. The end of this scour pipe shall be provided with a G. I. socket and plug. Details of scour pipe shall be as shown in Fig.12.

Delivery pipe- Delivery pipe shall be of 20 mm dia fixed with G. I.tee to prevent slipping. This shall be fixed at least 30 mm above the bottom slab of the tank to prevent silt at the bottom of tank entering it.

Over flow pipe - This shall be of 25 mm G. I. socket at the internal end and shall be fixed at the free board level of the tank at a convenient point to drain out over flow. The length of pipe including G. I. socket shall be 30 cm. The outer end of the over flow pipe shall be threaded.

Inlet pipe - This shall be 20 mm G. I. Pipe with 20 mm socket at internal end and socket or elbow at the outer end as required. It shall be fixed at the free board level.

Mosquito proof coupling - Mosquito Proof coupling  of rigid PVC or any other suitable material as per approved municipal design and approved by the Engineer with sieve No. 725 dia perforations shall be provided to the over flow pipe.

Ball valve - Ball valve with plastic float of specified size and pressure shall be provided to each tank. The ball valve shall be of brass. It shall be securely fixed to the tank in continuation of the inlet pipe and set in such a position that body of the ball valve does not submerge when the tank is full up to water line. The ball valve shall be so adjusted as to limit the level of the water in the tank at 25 mm below the lip of over flow pipe. Specification of ball valve shall be as given.

Mosquito proof c. i. hinged cover - Each tank shall be provided with 425 mm dia. standard mosquito proof C. I. hinged cover weighing 8.15 kg. and frame weighing 6.80 kg. with locking arrangement, as shown in Fig. 12. The frame shall be fixed to the top slab while precasting the same. This shall be provided in one corner convenient to the position of the ball valve as per the direction of the engineer.

13.21.7. Plaster

The base slab and the side walls will be plastered from inside with 15 mm thick cement mortar 1:3 (1 cement : 3 fine sand).  This plaster shall be done within one week of construction of the side walls. The junctions of the wall and the base slab in the interior and those between walls shall be rounded with mortar 1:3 while doing internal plaster all the joints of the inlet, delivery, scour and over flow pipes shall be made completely leak proof.

 A coat of neat cement punning shall be applied to the plaster on the surface of the walls and the base slab on the inner side of the tank. This plaster and neat cement punning shall also be carried over the top of the side the tank. This plaster and neat cement punning shall also be carried over the top of the side walls of the tank to serve as bearing plaster for the top side.

The external wall of the tank shall be plastered with 12 mm thick cement mortar 1:4 (1 cement : 4 fine sand).

13.21.8. Curing - Curing of R. C. C. and brick work and plastering shall be as per specifications Vol. II 1991-92.  The tank shall be filled with water after 28 days of completion of brick work. The tank shall be filled with water on the first day for half the capacity and to the full level a day thereafter. In order to prevent cracks developing in concrete due to shrinkage, the water in the tank shall be kept till such time, the tank is put into use when it shall be properly scoured.

13.21.9. Top Slab - The top slab shall be of precast reinforced cement concrete of 1:2:4 mix, 5 cm thick. The details of reinforcement shall be as shown in Fig. 12. The size of the top slab shall be such that it projects by 15 mm on all sides beyond the external finished faces of the tank wall. The top of the slab shall be rendered smooth while casting. While casting top slab, the frame of the C. I. hinged cover shall be fixed before hand so that it is embedded in concrete.

13.21.10. Testing - The tank shall be tested for water tightness at full supply level. The requirement of the test shall be deemed to be satisfied, if the external faces show no sign of leakage and remain apparently dry over the period of observation of seven days, after allowing a seven day period for absorption after filling.  If the structures show signs of wetness necessary rectification shall be carried out till it becomes leak proof after further testing.

13.21.11. Measurements - Water storage tank shall be enumerated.

13.21.12.  Rate - Unless otherwise specified the rate shall include the cost of materials and labour involved in all the operations described above including centering and shuttering with the exception of the following:-

(a)  Supports for the tank including projection of monolithic supporting beam below the bottom of the base slab.(b)  Bearing plaster over the supports of the tank.(c)  Cost of inlet and delivery pipes including fittings. Nothing extra shall be paid for fixing these pipes as described above.

13.22. SPECIFICATIONS FOR POLYETHYLENE WATER STORAGE TANKS

13.22.1. Material - Polyethylene used for manufacture of tanks and manhole lids may be high density (HDPE), low density (LDPE) or linear low density (LLDPE) and shall conform to IS : 10146. Polyethylene shall be compounded with carbon black so as to make the  tank resistant to ultra violet rays form the sun. The percentage of carbon black content in polyethylene shall be 2.5 ± 0.5 per cent and it shall be uniformly distributed. The materials used for the manufacture of tank, manhole lid and fittings shall be such that they neither contaminate the water nor impart any taste, colour, odour or toxity to water.

13.22.2. Manufacture and finish -The tanks shall be manufactured by rotational moulding process. Each tank and the manhole lid shall be single piece having arrangement for fixing and locking the manhole lid with the tanks. Excess material at the mould parting line and near the top rim shall be neatly cut and finished. The internal and external surface of the tanks shall be smooth, clean and free from didden internal defects like air bubbles, pit and metallic or other foreign material inclusion. Capacity of the tank, minimum weight of the empty tank (without manhole lid) and the manufacture brand name shall be embossed on the top surface of the tank near manhole.

13.22.3. Shape, Size and Capacity - The tank shall be cylindrical vertical with closed top having a manhole.  Diameter and height of the tank of various capacities shall be as per manufacturer’s specifications and a clearance of ± 3 per cent shall be permitted on these dimensions. Capacity of the tank or up to the bottom of the inlet location whichever is less. Capacity of the tank shall be specified. Extra capacity if any shall be ignored.

13.22.4. Weight and Wall Thickness:

Minimum weight of the empty tank (exclusive of manhole lid fittings) and the minimum wall thickness of top, bottom and sides shall be specified in Table 20. Wall thickness shall be checked beyond 150 mm of the edge where the direction the plane of tank surface changes.

13.22.5. Installation and Fittings:

The flat base of the tank shall be fully supported over its whole bottom area on a durable rigid flat and level platform sufficiently strong to stand without deflection the weight of the tank when fully filled with water. Depending upon the capacity and location tanks may be suitably anchored as per the directions of the Engineer. For inlet, outlet and other connections fully threaded GI., HDPE or PVC connections with hexagonal check nuts and washers on either side of the tank wall shall be provided. Holes for threaded connections shall be drilled and not punched. Pipes entering of leaving the tank shall be provided with unions and suitably supported on a firm base to avoid damage to the tank walls.

13.22.6. Manhole lid:

The lid shall rest evenly and fit over the rim of the manhole so as to prevent the ingress of any foreign matter into the tank. The lid shall be provided with suitable arrangement for locking it with the tank. The tank and its components shall conform to the local bye-laws for preventions of mosquito menace.

13.22.7. Measurements:

Dimensions shall be measured to the nearest cm. and weight of the empty tank shall be recorded to the nearest 100g. Capacity of the tank as defined 13.22.3 shall be calculated to the nearest litre.

Table 20

Sl. No.

Capacity litres

Minimum Wall

Thickness mm

Minimum Weight

of empty Tank kg

1

200

4.4

7.8

2

300

4.4

9.0

 

400

5.5

15.

 

500

6.0

18.0

 

700

6.6

23.5

 

1000

7.0

33.0

 

1250

7.0

40.0

 

1500

7.0

47.0

 

1700

7.0

54.0

 

2000

8.2

64.0

 

2500

8.2

81.0

 

3000

8.8

96.0

 

4000

13.4

138.0

 

5000

13.7

191.0

 

6000

13.7

209.0

 

7500

13.7

250.0

 

10000

11.5

363.0

 

15000

11.5

550.0

 

20000

13.2

814.0

13.22.8. Rates - The rate shall include the cost of the tank, manhole lid, carriage and delivery at the place specified. Hoisting, installation, fittings, platform and anchoring shall be payable separately.

13.23. SPECIFICATIONS FOR R. C. C. STORAGE TANKS - These tanks shall be cast in situ, circular / rectangular in shape and 270 and 540 litres capacity. These shall be as per approved drawing.

The mix of RCC shall be 1:1.5:3 for walls and bottom slab and 1:2:4 for top slab. The specification for RCC shall be as prescribed.  The top slab shall have the cover of 2 mm thick M. S. sheet 35 mm x 35 mm size having frame of angle iron 20x20x5 mm size. The detailed specifications shall be as prescribed under steel work.

13.23.2. Fittings - The flat base of the tank shall be fully supported over its whole bottom area on a durable rigid flat and level platform sufficiently strong to stand without deflection the weight of the tank when fully filled with water. Depending upon the capacity and location tanks may be suitably anchored as per the directions of the Engineer. For inlet, outlet and other connections fully threaded GI., HDPE or PVC connections with hexagonal check nuts and washers on either side of the tank wall shall be provided. Holes for threaded connections shall be drilled and not punched. Pipes entering of leaving the tank shall be provided with unions and suitably supported on a firm base to avoid damage to the tank walls.

13.24. SPECIFICATIONS FOR FIXING R. C. C. OR P. V. C. STORAGE TANK:-

13.24.1. Location - Tank shall be located nearest to the fittings for which water is to be supplied. It should not be visible as far as possible from the main road and compound of the buildings.  The overflow pipe shall discharge at a convenient and visible point so that it does not damage the building and does not prove a nuisance, should be tank go out of order.

13.24.2. Hoisting - The hoisting of tanks into position, as directed by the engineer, shall be carried so that no part of the tank or of structure is damaged in the operation. The tank shall be installed in position truly level. The supports for the tanks shall be provided as ordered and shall be measured and paid for separately.

13.24.3. Measurements - Water storage tanks shall be counted in numbers for the complete job.

13.24.4. Rate - The rate shall include the cost of materials and labour involved in all the operations described above except the cost of external painting providing and fixing stop cock and supports for storage tank for which separate payment shall be made under respective items of work.

13.25. SPECIFICATIONS FOR TUBE WELLS WITH HAND PUMPS

13.25.1. Casing Pipe - The casing pipe shall be of M. S. or W. I. of 100 mm dia. and strong enough to stand hammering and vibrations to which it is subjects.

13.25.2. Filter and Brass Strainer - The filter shall consist of G. I. pipe of the required diameter with 15 mm diameter holes covered with brass strainer both inside and outside.  It shall have a driving point riveted or welded to it.

13.25.3. Hand Pump - This shall be of approved quality. It shall be complete with necessary bolt and nuts for joining to the masonry or concrete base.

Annexure 13.A.1

TOLERANCES FOR CAST IRON (CENTRIFUGALLY CAST) PIPES (Clause 13.2.13)

Tolerance in Diameter Dimensions

Nominal diameter(DN)

Tolerance in mm

a) External diameter of barrel (DE)

All diameters.   

± ½ F= ±(4.5+0.0015 DN)

b) Internal diameter of socket (DI)

All diameters.   

±1/3 F=±(3±0.001DN)

c) Depth of socket (P)  

(1) Up to and including 600 mm      

± 5

 

(2) Over 600 mm and up to and including 1000 mm

± 10

Note:

1)   F is the caulking space of the joint in millimeters and is equal to 9 + 0.003 DN.

2)  The jointing tolerance applicable to rubber joints (mechanical or push in joints) shall be as specified by their manufacturer and shall be within the tolerances specified above.

Tolerance on Thickness:

Dimensions

Tolerance in mm

a) Wall thickness

- (1 + 0.05 e)

b) Flange thickness

± (2 + 0.05 b)

Where  e = is the thickness of the wall in millimeters and

            b = is the thickness of the flange in millimeters.

Tolerance in Length:

Type of Casting

Tolerance in mm

a) Socket and spigot, and plain ended pipes   

± 25

b) Flanged pipes          

± 10

Annexure 13.A.2

TOLERANCES FOR SPECIALS OF CAST IRON PIPES (Clause 13.2.14)

Tolerances in Diameter:

Dimension

Nature of Joint

Nominal diameter (DN)

Tolerance in mm

External diameter of spigot (DE)      

Lead joint

All diameters

± 1/2F or ± (4.5 +0.0015 DN)

Internal diameter of socket (DI)

Lead joint

All diameters

± 1/3 or ± (3 + 0.001 DN)

Depth of socket (P)

Lead joint         

Up to and including600 mm

± 5

Over 600 mm up to and including 1000 mm       

± 10

Over 1000 mm up to and including 1500 mm       

± 15

Tolerances in Thickness:

Dimension

Tolerance in mm

Wall thickness  

- (2 + 0.05 e)

Flange thickness

± (3 + 0.05 b)

Where e = the standard thickness of the wall in millimeters, and

            b = the standard thickness of the flange in millimeters.

Tolerance in Lengths

Type of fitting

Nominal diameter

Tolerance in mm

Socket fittings and flange

Up to and including 450 mm

± 20

spigot pieces   

Over 450 mm

± 20 – 30

Flanged fittings

All diameters

± 10

Annexure 13.A.3

PARTICULARS OF MEDIUM GRADE G. I. PIPES (Clause 13.2.14)

Nominal Bore

Dimension of Pipes

Weight of pipe

Outside diameter

Thickness

Plain end

Screwed end socket

(mm)

Max. (mm)

Min. (mm)

(mm)

Kg/m

Kg/m

6

13.6

9.8

2.0

0.427

0.430

8

14.0

13.2

2.35

0.677

0.681

10

17.5

16.7

2.35

0.886

0.892

15

21.8

21.0

2.65

1.27

1.28

20

27.3

26.5

2.65

1.64

1.65

25

34.2

33.3

3.25

2.51

2.53

32

42.9

42.0

3.25

3.23

3.26

40

48.8

47.9

3.25

3.72

3.76

50

60.8

59.7

3.65

5.24

5.31

65

76.6

75.3

3.65

6.69

6.81

80

89.9

88.0

4.05

8.68

8.85

100

115.0

113.1

4.50

12.40

12.70

125

140.8

138.5

4.85

16.50

17.00

150

166.5

163.9

4.85

19.60

20.20

Tolerance in Thickness and Weight.

a) Thickness

1. Butt welded medium tubes. + Not limited

   - 10 percent.

2. Seamless tubes  + Not limited

                               - 12.5 percent.

b) Weight

1. Single tube (irrespective of quantity) + 10 percent.

  - 8 percent

2. For quantities of less than 150 m of one  + 10 percent

size  - 8 percent

3. For quantities of 150 m and over of one size  ± 4 percent

Annexure 13.A.4

UNPLASTICISED RIGID P. V. C. PIPES

(Clause 13.2.15.4)

A) For Internal work

Outside dia in mm

Tolerance on outside dia

Wall thickness in mm for 10kg / sq.cm for working pressure

Min.

Max.

20

+ 0.3

2.8

3.3

25

+ 0.3

2.9

3.4

32

+ 0.3

3.4

3.9

40

+ 0.3

3.6

4.2

50

+ 0.3

3.7

4.3

B) For External Work

Outside Diameter

Tolerance on outside dia

Wall thickness for working pressure

2.5kgf/cm2

4kgf/cm2

6kgf/cm2

10kgf/cm2

Min

Max.

Min

Max.

Min

Max.

Min

Max.

16

+0.3

 

 

 

 

 

 

1.1

1.5

20

+0.3

 

 

 

 

 

 

1.1

1.5

25

+0.3

 

 

 

 

 

 

1.4

1.8

32

+0.3

 

 

 

 

 

 

1.8

2.2

40

+0.3

 

 

 

 

1.4

1.8

2.2

2.7

50

+0.3

 

 

1.2

1.6

1.7

2.1

2.8

3.3

63

+0.3

 

 

1.5

1.9

2.2

2.7

3.5

4.1

75

+0.3

 

 

1.8

2.2

2.6

3.1

4.2

4.9

90

+0.3

1.3

1.7

2.1

2.6

3.1

3.7

5.0

5.7

110

+ 0.4

1.6

2.0

2.5

3.0

3.7

4.3

6.1

7.0

125

+0.4

1.8

2.2

2.9

3.4

4.3

5.0

6.9

7.7

140

+0.5

2.0

2.4

3.2

3.8

4.8

5.5

7.7

8.7

160

+0.5

2.3

2.8

3.7

4.3

5.4

6.2

8.8

9.9

180

+0.6

2.6

3.1

4.2

4.9

6.1

7.0

9.9

11.1

200

+0.6

2.9

3.4

4.6

5.3

6.8

7.7

11.0

12.3

225

+0.7

3.3

3.9

5.2

6.0

7.6

8.6

12.4

13.9

250

+0.8

3.6

4.2

5.7

6.5

8.5

9.6

13.8

15.4

280

+0.9

4.1

4.8

6.4

7.3

9.5

13.7

15.4

17.2

315

+1.0

4.6

5.3

7.2

8.2

13.7

12.0

17.3

19.3

Annexure 13.A.5

PROCEDURE FOR PRESSURE TEST

(Clause 13.5.6)

1.  Each valved section of the pipe shall be slowly filled with water and all air shall be expelled from the pipe through hydrants and blow-off. If these are not available at high places, necessary tapping may be made at points of highest elevation before the test is made and plugs inserted after the tests have been completed.

2.  If the trench has been partially back-filled the specified pressure based on the elevation of the lowest point of the line or section under test and corrected to the elevation of the test gauge, shall be applied by means of a pump connected to the pipe in a manner satisfactory to the engineer. The duration of the test shall not be less than 5 minutes.

3. Examination under Pressure: All exposed pipes, fittings, valves, hydrants and joints should be carefully examined during the open-trench test. When the joints are made with cement and show seepage or slight leakage, such joints shall be cut out and replaced as directed by the authority. Any cracked or defective pipes, fittings, valves or hydrants discovered in consequence of this pressure test shall be removed and replaced by sound material and the test shall be repeated until satisfactory to the engineer.

4.  If the trench has been back-filled to the top, the section shall be first subjected to water pressure normal to the area and the exposed parts shall be carefully examined. If any defects are found, they shall be repaired and the pressure test repeated until no defects are found. The duration of the final pressure tests shall be at least one hour.

Procedure for Leakage Test

1. Leakage is defined as the quantity of water to be supplied into the newly laid pipe, or any valved section thereof, necessary to maintain the specified leakage test pressure after the pipe has been filled with water and the air expelled.

No pipe installation shall be accepted until the leakage is less than the number of cm3/h determined by the formula

           N x D x P

 ql =  ------------

            3.3

Where ql =  the allowable leakage in cm3/h.

            N = number of joints in the length of the pipe line.

            D = diameter in mm, and

            P = the average test pressure during the leakage testing kg/cm2.

2. Variation from Permissible Leakage: Should any test of pipe laid in position discloses leakage greater than that specified in para 5 the defective joints shall be repaired until the leakage is within the specified allowance. 

Annexure 13-A.6

LIST OF BUREAU OF INDIAN STANDARDS CODES (IS) *

Sl.

IS. No.

Subject

1

269-1989

Specification for 33 grade ordinary Portland cement (4th Revision) (Amendments 3)

2

554-1999

Dimensions for pipe threads where pressure tight joints are required on the threads (3rd revision) (Reaffirmed 1990)

3

778-1984

Specification for copper alloy gate, and check valves for water works purposes (4th revision) (Amendments2) (Reaffirmed 1990)

4

779-1994

Specification for water meters (domestic type) (5th revision) (Amendments 3) (Reaffirmed 1991)

5

780-1984

Specification for sluice valves for water works purposes (50 to 300 mm size) (6th revision) (Amendments 3) (Reaffirmed 1990)

6

781-1984

Specification for cast copper alloy screw down bib and stop valves for water services (3rd revision) (Amendment 1) (Reaffirmed 1990)

7

782-1979

Specification for caulking lead (3rd revision) (Reaffirmed 1992)

8

909-1992

Specification for underground fire hydrant, sluice valve type (3rd revision)

9

1239 (Part 1)-2004

Specification for mild steel tubes tubulars and other wrought steel fittings, Part 1 mild steel tubes (5th revision) (Amendments 3) (Reaffirmed 1985).

9A

1239 (Part II)- 1992

Specification for mild steel tubes tubulars and other wrought steel fittings, Part II mild steel tubulars and other wrought steel pipe fittings (3rd revision) (Amendments 1)

10

1536-2001

Specification for centrifugally cast (spun) iron pressure pipes for water gas and sewage (3rd revision) (Amendments 2) (Reaffirmed 1993)

11

1537-1976

Specification for vertically cast iron pressure pipes for water, gas and sewage (1st revision) (Amendments 5) (Reaffirmed 1991)

12

(1538-1993)*

Specification cast iron fittings for pressure pipes for      water, gas and sewage, (3rd revision) superceding IS 1538 (Parts 1 to 24)

13

1592- 2003

Specification for Asbestos cement pressure pipes (3rd revision)

14

1703-1989

Specification for copper alloy float valves (horizontal plunger type) for water supply fittings (3rd revision)

15

2556 (Part IX)-2004

Specification for vitreous sanitary appliances vitreous China) Part XI specific requirements for shower rose (1st revision) (Reaffirmed 1990)

16

2692-2000

Specification for ferrules for water services (2nd revision) (Amendment 1)

17

2906-1984           

Specification for sluice valves for water works purposes (350 to 1200 mm size) (3rd revision) (Amendments 3)  (Reaffirmed 1990)

18

4736-1986

Hot-dip Zinc Coatings on mild steel tubes (1st revision) (Amendment 1) (Reaffirmed 1992)

19

4984-1995

Specification for high density polyethylene pipes for potable water supplies, sewage and industrial effluents (3rd revision)

20

4827-1983

Electroplated coatings of nickel and chromium on copper and copper alloys (1st revision) (withdrawn)

21

4985-2000

Specification for unplasticised PVC pipes for potable water supplies (2nd revision) (Amendment 1)

22

5382-1985

Rubber sealing rings for gas mains, water mains and sewers (1st revision) (Amendment 1) (Reaffirmed 1994)

23

5913 – 2003

Method of test for asbestos cement products (1st revision)

24

9762 – 1994

Specification for polyethylene floats (spherical) for float valves

Annexure 13-A.7

ADDITIONAL SPECIFICATIONS FOR WATER SUPPLY WORKS

(Extract from SP 62 (SfT):1997 of BIS)

General

This part deals with general requirements of plumbing connected to public water supply and installation of water supply system consisting of water service pipe, water distribution pipe, connecting pipes, fittings, valves and all related appurtenances in or adjacent to buildings.

The water supply requirements of buildings and design of distribution systems shall be as per IS: 1172 -1993 and IS: 2065-1983 respectively.

Note: The illustration is not intended to indicate recommended positions of underground storage tank (where provided), pipes, etc., and this will depend on local situation.

Figure 1 is a typical sketch of the different types of water supply pipes in buildings.

Excavation, if required, shall be as prescribed.

Materials

Pipes

Pipes may be of any of the following materials:

a)  Cast iron, vertically cast or centrifugally (spun) cast to IS: 1536-1989 or IS: 1537-1976.

b)  Mild steel tubes and tubulars to IS: 1239 (Part 1)-1990.

c)  Asbestos cement to IS: 1626 (Part 1) -1991 and IS: 1592-1989.

d)  Polyethylene to IS: 3076-1985 and IS: 4984-1987.

e)  Un-plasticized PVC to IS: 4985 -1988.

f)  Copper to IS: 1545-1982.

g)  Brass to IS: 407-1981.

h)  Lead to IS: 404 (Part 1) -1993.

Choice of Pipes - The materials for piping and fittings, shall be resistant to corrosion both inside and outside or shall be suitably protected. Lead piping shall not be used for conveying domestic water supply; they may however be used for flushing and overflow pipes. Copper piping may be used for hot water supply systems, provided water is not capable of dissolving an undue amount of copper. In using asbestos cement pipes adequate precaution shall be taken while laying back-filling.  Mild steel tubes used in plumbing shall be of medium class to IS: 1239 (Part 1)-1990. Polyethylene and PVC pipes should not be laid on hot surfaces or in too close a proximity to the hot water pipes. Care should also be taken to avoid locations where they are likely to be exposed to atmosphere charged with coal gas.

CONVEYANCE AND DISTRIBUTION OF WATER WITHIN THE PREMISES

Basic Principles

Some of the details of plumbing which are considered necessary for properly designed, acceptably installed and adequately maintained plumbing systems are given below from (a) to (k). Though the details of a construction may vary, the basic sanitary and safety principles are the same, and they merit serious study. Further more in the event of any unforeseen situation not covered here, the principles enumerated may serve as useful guides.

a)  Wholesome water supply provided for drinking and culinary purposes shall not be liable to contamination from any less satisfactory water. There shall therefore be no cross connection whatsoever between a pipe or fitting conveying or containing whole some water and pipe or fitting containing impure water or water liable for contamination or of uncertain quality of water which has been used for any purpose.

The provision of reflux or non-return valves or closed and sealed stop valves shall not be constructed as a permissible substitute for complete absence of cross connection.

b) The design of the pipe shall be such that there is no possibility of back flow towards the source of supply from any cistern or appliance whether by siphonage or otherwise. Reflux or non-return valves shall not be relied upon to prevent such back flow.

c)  Where a supply of less satisfactory water becomes inevitable as an alternative or is required to be mixed with wholesome water, it shall be delivered only into a cistern, and by a pipe fitting discharging into the air gap at a height above the top edge of the cistern equal to twice its nominal bore, and in no case less than 150 mm.  It is necessary to maintain definite air gap in all appliances or taps used in water closets.

d)  All pipe work shall be so designed, laid or fixed, and maintained as to be and to remain completely water tight, thereby avoiding waste of water, damage to property and risk of contamination of the water conveyed.

e)  No piping shall be laid or fixed so as to pass into, through or adjoining any sewer, scour outlet or drain or any manhole connected therewith nor through any ash pit or manure pit or any  material of such nature that would be likely to cause undue deterioration of the pipe. Where lines have to be laid in closer proximity to electric cables or in corrosive soils, adequate precautions should be taken to avoid electrical accidents and corrosion.

f)  Where the laying of any pipe through corrosive soil or previous material is unavoidable, the piping shall be properly protected from contact with such soil or material. Any existing pipe or fitting laid or fixed, which does not comply with the above requirements, shall be removed immediately and re-laid  in conformity with the above requirements.

g) To reduce friction losses, piping shall be as smooth as possible inside. Methods of jointing shall be such as to avoid internal roughness and projection at the joints, whether of the joining materials or otherwise.

h) Change in diameter and in direction shall be gradual rather than abrupt to avoid undue loss of head. No bend or curve in piping shall be made which is likely to materially diminish, or alter the cross-section.

i) Underground piping shall be laid at such a depth that it is unlikely to be damaged by frost or traffic loads and vibrations. It shall not be laid in ground liable to subsidence; but where such ground cannot be avoided, special precautions shall be taken to avoid damage to the piping. Where piping has to be laid across recently disturbed ground, the ground shall be thoroughly consolidated so as to provide a continuous and even support.

j)  No boiler for generating steam or closed boilers of any description or any machinery shall be supplied direct from a service or supply pipe. Every such boiler or equipment shall be supplied from a feed cistern.

General requirements of pipe work

The following general principles shall comply in the layout and planning of the pipe work.

Communication Pipes

a)  Every premises shall have its own separate communication pipe for supply of water to the Authority. In the case of a group or blocks of premises, the same communication pipe may supply water to more than one premises.

b)  The communication pipe between the water main and the stopcock at the boundary of the premises shall be laid by the Authority.

c)  Connection up to 50 mm dia may be made on the water main by means of screwed ferrules, provided the size of the connection does not exceed one-third that the size of the water main. In all other cases, the connection shall be made by a T –branch off the water main.

d)  As far as possible, the communication pipe and the underground service pipe shall be laid at right angles to the main and in approximately straight lines to facilitate location for repairs.

e)  Every communication pipe shall have a stopcock and meter inserted in it. The waterway of such fitting shall not be less than the internal sectional area of the communication pipe and the fittings shall be located within the premises at a conspicuous place accessible to the Authority which shall have exclusive control over it.

Consumer Pipes

a)  No consumer pipe shall be laid in the premises to connect the communication pipe without the permission of the Authority.

b)  The consumer pipe within the premises shall be laid underground with a suitable cover to safeguard against damage from traffic and extremes of weather.

c)  To control the branch pipe to each separately occupied part of a building a stop valve shall be fixed to minimize the interruption of supply during repairs. All such stop valves shall be fixed in accessible positions and properly protected. To provide for drinking or culinary purposes, direct taps shall be provided on the branch pipes connected directed to the consumer pipe. In case of multi-storied buildings, down take pipes shall be supplied from overhead tanks.

d)  Pumps shall not be allowed on the service pipe, as they cause a drop in pressure on the suction side, thereby affecting the supply to the adjoining properties. In cases where pumping is required, a properly protected storage tank of adequate capacity shall be provided to feed the pump.

e) No direct boosting (by booster pumps) shall be allowed from the service pipes (communication and consumer pipes).

f)  Consumer pipes shall be so designed and constructed as to avoid air locks. Draining taps shall be provided at the lowest points from which the piping shall rise continuously to the drain off taps.

g)  Consumer pipes shall be so designed as to reduce the production and transmission of noise as much as possible.

h) Consumer pipes in roof spaces, unventilated air spaces, under-floors or in basements shall be protected against corrosion.

i)  Consumer pipe shall be so located that they are not unduly exposed to accidental damage and shall be fixed in such positions as to facilitate cleaning and avoid accumulations of dirt.

j)  All consumer pipes shall be so laid as to permit expansion and contraction or other movements.

Prohibited Connections

a)  A service pipe shall not be connected to a distribution pipe, since such connections may permit back flow of water from a cistern into the service pipe, in certain circumstances, with subsequent damages of contamination and depletion of storage capacity. It might result in pipes and fittings being subjected to pressure higher than that for which they are designed and in flooding from overflowing cisterns.

b)  No pipe for conveyance or in connection with water supplied by the Authority shall communicate with any other receptacle used or capable of being used for conveyance other than water supplied by the Authority.

c)  Water storage tanks are provided no person shall connect or be permitted to connect any service pipe with any distribution pipe.

d)  No service pipe shall be connected directly to any water closet or a urinal. All such pipes shall be from flushing cisterns which shall be supplied from storage tank.

e)  No service or supply pipe shall be connected directly to any hot water system or to any other apparatus used for heating water other than through a feed cistern thereof.

Laying of pipes

Service pipes

a)  Service pipes less than 50 mm bore may be connected to mains by means of a right angled screwed down ferrule of non-ferrous metal conforming to IS 2692 : 1989, but the ferrule itself shall not be more than 25 mm bore. Ferrules of 20 mm and above shall not be used on mains of less than 100 mm bore. The main is drilled and tapped and the ferrule screwed in.  In case of large-sized trunk mains, this may be done by a tapping under pressure machine, which will obviate any interference with the use of the main.

b)  Service pipes of 50 mm and above shall be connected to special T-branches which have to be inserted into the line of the main. Special branch pipes shall also be used for service pipes of less than 50 mm bore where the bore of the main is not greater than thrice that of the service pipe.

c)  Precautions against contamination of the mains shall be taken when making a connection, and where risk exists, the main shall be subsequently disinfected. The underground water service pipe and the building sewer or drain shall be kept at a sufficient distance apart to the satisfaction of the Authority so as to prevent contamination of water. Water service pipes or any underground water pipes shall not be run or laid in the same trench as the building sewer or drainage pipe. Where this is unavoidable, the following conditions shall be fulfilled:

(1)  The bottom of the service pipe, at all points, shall be at least 30 cm above the top of the sewer line at its highest point.(2)  The water service pipe shall be placed on a solid shelf excavated at one side of the common trench.(3)  The number of joints in the service pipe shall be kept to a minimum.(4)  The materials and joints of sewer and water service pipe shall be installed in such a manner and shall possess the necessary strength and durability so as to prevent the escape of solids, liquids and gases there from due to temperature changes, settlement, vibrations and superimposed loads.

d)  The service pipe shall pass into or beneath the building at a depth below the external ground level of not less than 0.75 m (provided the foundation is deeper than 0.75 m) and at its point of entry through the structure should be accommodated in a sleeve which should have been solidly built in. The space between the pipe and sleeve shall be filled with bituminous or other suitable material for a minimum length of 15 cm at both ends.

e)  Care shall be taken to ensure that before the pipeline is charged all piping and fittings are clean internally and free from particles of sand or soil, metal fittings, etc. which besides causing obstruction may lead to failure by corrosion.

Securing and Supporting of Pipes:

a)  Lead piping of not more than 25 mm bore, in vertical runs, may be secured directly to brick walls (other than external walls) by iron pipe clamps driven into the wall joints, or may be secured to wooden battens or other wood work by iron or brass clips with ears for screw fixing, the clamps or clips or holder bats being at not more than 90 cm intervals.  Damage to the piping by the clamps shall be prevented by insertion of small lead pads.

b)  Copper piping shall be secured by copper or copper alloy clips direct to wood work, or by similar bracket clips built in to walls or screwed to plugs.

c)  Wrought iron and steel piping shall be secured in a manner similar to that used for copper piping, except that the clips shall be of iron and steel.

d)  Plastic pipes should be secured and supported in accordance with IS: 7634 (Part 2)-1975 and IS:  7634 (Part 3)-1975.

Spacing of Fixing for Internal Pipes - Fixing on internal pipes shall be spaced at regular intervals as given in Table 1.

Pipes Laid Through Ducts, Chases, Notches or Holes - Ducts or chases in walls for piping shall be provided during the building of the walls. If they are cut in the existing walls, they shall be finished sufficiently smooth and large enough for fixing the piping. In case of lead pipes, the joints may be wiped outside the duct, and the pipes eased back into the duct after jointing.

a) Wherever possible back-boards shall be provided in chases for fixing the piping, otherwise lead piping shall be protected from contact with lime or cement by building paper or felt. Where covers are provided to chases, they shall be fixed to the screws for easy removal.

b)  Piping laid in notches or holes shall not be subjected external pressure and shall be free to expand and contract without noise due to friction on the wood.

Lagging of Pipes

a)  Where lagged piping outside buildings is attached to walls, it shall be entirely covered all round with waterproof insulating material and shall not be in direct contact with the wall.  Where it passes through a wall, whether into a building or not, the lagging shall be continued along the pipe throughout the thickness of the wall, and where it emerges from the ground, the lagging shall be continued into the ground until the depth of 0.75 m is reached.

b)  Lagged piping connected to cisterns, enclosed by insulating casing shall pass at right angles through the casing and be lagged independently of the casing ; if the piping is sandwiched between the cistern and the casing, it will probably, not be sufficiently insulated.

c)  The minimum thickness of insulating material for lagging hot water piping inside buildings shall be 12 mm in the case of glass in fibre form, compressed felt, and felted slag or mineral wood and 20 mm in the case of asbestos,  85 percent magnesia, compressed backed cork and granulated cork (raw or baked).

d)  All lagging exposed to moist conditions shall be waterproof or covered with waterproofing.

Table 1 Spacing of fixing for internal piping

Kind of Piping

Size of Pipe(mm)

Interval for Horizontal Runs(m)

Interval for Vertical Runs(m)

Lead

All sizes

2

3

Copper, light gauge

15

1

2

 

20

2

2.5

 

32

2.5

3

 

40

2.5

3

 

50

2.5

3

 

65

3

3.5

 

80

3

3.5

 

100

3

3.5

Copper, heavy

15

2

2.5

Gauge, wrought

20

2.5

3

Iron and mild steel

25

2.5

3

 

32

2.5

3

 

40

3

3.5

 

50

3

3.5

 

65

3.5

5

 

80

3.5

5

 

100

4

5

Cast iron

50

2

2

 

80

2.5

2.5

 

100

2.5

2.5

Plastic 

20

0.70

1.5 times the horizontal spacing

 

25

0.75

 

 

32

0.825

 

 

40

0.975   

 

 

50

0.975   

 

JOINTING OF PIPES

Wrought iron and steel screwed pipes - Screwed wrought iron or steel piping may be jointed  with screwed and socketed joints. Care shall be taken to remove any burrs from the end of the pipes after Authority may be used together with a grummet of a few strands of fine yarn; but the compound shall contain no red lead.

Any threads exposed after jointing shall be painted, or in case of underground piping thickly coated with bituminous or other suitable composition to prevent corrosion. Screwed wrought iron or steel piping may also be jointed with screwed flanges.

Polyethylene and Unplasticized PVC Pipes - These pipes shall be joined in accordance with the recommendations of IS: 7634 (Part 2) -1975 and IS: 7634 (Part 3)-1975 respectively.

Asbestos Cement Pipes - Asbestos cement pipes are joined with flexible joints supplied by the manufacturer.

Lead Pipes - Lead and lead alloy pipes shall be joined with wiped solder joints or by other suitable methods. Lead and lead alloy piping shall be jointed to cast iron, wrought iron, steel or copper piping by the use of copper alloy screwed unions or ferrules.

Copper Pipes - Screwed copper piping shall be jointed with screwed copper-alloy fittings after treating the clean screw threads with raw linseed oil or other suitable jointing compound. Alternatively, the screw threads of the pipe and fittings may be tinned, and the joint heated to the melting point of the solder when being screwed.

a)  Plain copper piping shall be jointed with compression (manipulative or non-manipulative) or with capillary joints in each case using copper-alloy fittings, or by welding.  Only manipulative compression joints, that is, joints in which the pipe ends are flanged, belted or swaged, are suitable for use with fully annealed copper piping.

b)  In the case of the capillary joint, the pipe and the interior of the socket of the fitting shall be cleaned with steel wool, fluxing and fitted together and the joint heated to just above melting point of the solder, which is either provided in the fitting or is touched into the joint with a solder stick, and which then flows by capillary to fill the joint space. If the pipe is of fully annealed copper, its ends shall be made truly round before jointing.

c)  Copper piping may be autogenous welded or bronze welded, the latter giving the stronger joint. Copper to be welded shall be ‘deoxidized copper’ and not ‘tough pitch copper’.

d)  Copper piping of small diameter shall be jointed to cast iron, wrought iron or steel piping by the use of copper-alloy screwed unions or ferrules. For screwed copper piping of diameter, larger than 40 mm, a flange joint shall be used. The copper pipe shall have a copper-alloy flange screwed, brazed or welded on, and this shall be jointed to the iron or steel flange by alloy bolts or nuts.

Storage of water - Details of materials for use of storage tanks, grouping of storage tanks, filaments, etc., shall be as described in IS: 2065 -1983.

Cleaning and disinfection of the supply system - All water mains, communication pipes, service and distribution pipes used for water for domestic purposes shall be thoroughly and efficiently disinfected before being taken in to use and also after every major repair. The method of disinfection shall be subject to the approval of the Authority.

Similarly storage tanks and down take distribution pipes shall also be disinfected.

Inspection, testing and maintenance - Inspection, testing and maintenance shall be according to IS: 2065 -1983.

Requirements of other work

Sanitary Installations - The selection, installation and maintenance of sanitary appliances shall be according to IS: 2064-1993.

Plumbing Installations in Multi-storeyed Buildings - Plumbing in multi-storeyed buildings shall conform to IS: 12183 (Part 1)-1987.

Domestic Hot Water Installations - This shall conform to IS: 7558 -1974.

Annexure 13-A.8

SPECIFICATIONS FOR LOW DENSITY POLYETHYLENE PIPES FOR POTABLE WATER SUPPLIES (Extract of IS: 3076-1985)

1.  Scope

1.1. This standard lays down requirements for low density black polyethylene pipes of outside diameters up to 140 mm for use in potable water supplies.

* Code of practice for plastics pipe work for potable water supplies; (Part 2) Laying and jointing polyethylene (PE) pies.

2. Classification of Pipes

2.1. The pipes shall be classified by pressure ratings (working pressures at 27 °C) as follows:

Class of pipes

Working pressure

Class 1

0.25 Mpa

Class 2

0.4. Mpa

Class 3

0.6. Mpa

Class 4

1.0 Mpa

Note: The above pipes are recommended for water temperature up to + 38°C.  the pipes can also be used up to a temperature of - 40°C.  The recommended maximum working stress for the material at 20°C in pipes form is 3.2 Mpa for 50 years of life.  The creep rupture of the pipe diminishes with the increase in temperature above 20°c and, therefore, the working pressure should be modified as given in Fig.1.

3. Material

3.1. The low density polyethylene used for the manufacture of the pipes shall have a base density (virgin polymer) of not more than 0.928 g/ml. At 27°C the material shall conform to Type WA of IS: 3395-1965*.  Addition of not more than 10 percent of the manufacturer’s own rework material resulting from the manufacture of pipes to this standard is permissible.  No other rework material shall be used.

3.1.1. The material used for extrusion shall be dried to bring the moisture content to less than 0.1 percent by mass.

3.1.2. The percentage of antioxidant used shall be not more than 0.3 percent by mass.  The antioxidants used shall be physiologically harmless and shall be selected from the list given in 3.4.2.1(a) of IS: 10141-1982 †. 

3.2. The carbon black used shall comply with the following

(a) Density – 1.5 to 2.0 g/ml (b) Volatile matter – Not more than when tested in accordance with Appendix A. (c) Toluene extract – Not more than 0.1percent by mass when determined by the method described in Appendix B.

Fig.1 Graph giving the maximum continuous working pressure (Multiplication factor) for temperature upto 380 c

Note:  the average particle size may not exceed 0.06 um.

* Specification for low density polyethylene materials for molding and extrusion

† Positive list of constituents of polyethylene in contact with foodstuffs pharmaceuticals and drinking water.

3.2.1. When tested in accordance with IS: 2530-1963*.

a)  The percentage of carbon black in the material shall be 2.5. ± 0.5 by mass, and

b)  The dispersion of carbon black shall be satisfactory.

4. Dimensions Of Pipes

4.1. The outside diameters and wall thickness of the pipes shall be as given in Table.1.

* Methods of test for polyethylene molding materials and polyethylene compounds.

4.1.1. The outside diameter of a pipe of size up to 110 mm shall be the average of 4 measurements taken at 45° round the pipe.  For sizes greater than 110 mm the diameter shall be obtained by dividing the circumference of the pipe by 3.142 and rounding off to the nearest 0.1mm.  The circumference shall be measured by using a flexible tape.  Circometer may also be used for determination of diameter.

4.1.2. The wall thickness shall be measured with a dial vernier / ball ended micrometer.

4.1.3. The resulting dimensions shall be expressed to the nearest 0.1mm.

Note: In case of dispute the dimensions shall be measured after conditions the pipes at 27 ± 1°C for 4 hours.

Table 1 Dimensions of low density polyethylene pipes (Clause 4.1.)

All dimensions in millimeters.

Out side diameter

Tolerance on outside diameter

Well thickness for working pressures

Class I

(0.25 Mpa)

Class 2

(0.4 Mpa)

Class 3

(0.6 Mpa)

Class 4

(1.0 Mpa)

Min

Max

Min

Max

Min

Max

Min

Max

10

+0.3

-

-

-

-

-

-

-

-

12

+0.3

-

-

-

-

-

-

2.0

2.4

16

+0.3

-

-

-

-

-

-

2.7

3.2

20

+0.3

-

-

-

-

2.2

2.7

3.3

3.9

25

+0.3

-

-

-

-

2.7

3.2

4.2

4.9

32

+0.3

-

-

2.4

2.9

3.4

4.0

5.3

6.1

40

+0.3

-

2.3

3.0

3.5

4.3

5.0

6.6

7.5

50

+0.4

1.9

2.9

3.7

4.3

5.3

6.1

8.3

9.4

63

+0.5

2.4

3.5

4.7

5.4

6.7

7.6

10.4

11.7

75

+0.6

3.0

4.2

5.5

6.3

8.0

9.0

-

-

90

+0.7

4.3

5.0

6.6

7.5

9.6

10.8

-

-

110

+0.8

5.2

6.0

7.5

9.2

11.7

13.1

-

-

125

+1.2

5.9

6.7

9.2

10.4

-

-

-

-

140

+1.3

6.6

7.5

10.3

11.6

-

-

-

-

5. Visual appearance

5.1. The internal and external surfaces of the pipes shall be smooth, clean and free from grooving and other defects.  The ends shall be cleanly cut and shall be square with the axis of the pipe.  Slight shallow longitudinal grooves or irregularities in the wall thickness shall be permissible provided the wall thickness remains within the permissible limits.

6. Performance requirements

6.1. Hydraulic characteristics - When subjected to internal pressure creep rupture test in accordance with the procedure given in Appendix, C , the pipe shall show no signs of localized swelling, leakage or weeping and shall not rupture during the prescribed test duration.  The temperatures duration of test and stresses for quality and acceptance tests shall be as given in Table .2.

Table 2 Requirements for internal pressure creep rupture test.

Test

Test temperature

Test duration (minimum holding time)

Induced stress

 °C

MIN

Mpa

Quality test

20

1

7.8

Acceptance test

70

100

2.9

6.2. Reversion Test - A pipe length of 200 mm shall be placed horizontally on a support in an air oven or a suitable liquid bath at a temperature of 100 ± 2°C for 60 minutes so that the dimensional changes in the pipe section are not impeded.  After cooling to room temperature, they dimensional change of the pipe section shall be measured in the longitudinal direction and the deviation from the initial length shall be calculated and stated in percentage.  The dimension shall not change by more than 3 percent in the longitudinal direction.

6.3. Tensile test - The tensile strength of the material and elongation at break at 27 ± 1°c for different thickness of the pipes shall be as follows:

Thickness of pipe wall

Tensile Strength

Elongation at Break min

£ 5 mm

8.85 Mpa

350 percent

> 5 mm

8.85 Mpa

200 percent

6.3.1. Test Piece - The test piece shall consist of a dumb-bell punched from points on the circumference of the pipe 90°C apart.  The shape of the test piece shall be as shown in Fig.2.

Note: for all pipes of wall thickness over 10 mm, the thickness of the test piece should be reduced 10 mm by machining the internal surface.

Fig. 2 Shape of a Dumb-bell test piece for tensile test

Note: For all pipes of wall thickness over 10mm, the thickness of the test piece should be reduced to 10mm by machining the internal surface.

All dimensions in millimetres.

6.3.2. Procedure - The test piece shall be conditioned so that it is at a temperature of 27 ± 2°C immediately before test.  The test shall be carried out as given in 6 of IS:2530 – 1963 * except that the rate of separation of jaws shall be not less than 12 mm and not more than 24 mm per minute per millimeter length of the parallel portion of the test piece between the grips.

 * Methods of test for polyethylene molding materials and polyethylene compounds.

7. Supply of pipes

7.1. The pipes shall be supplied on coil of nominal lengths 25, 50,100,150 and 200 m unless otherwise agreed to between the purchaser and the supplier.  Each coil shall contain not less than the specified nominal length.  The ends of the pipes shall be cut at right angles to the pipe axis.

8. Coiling

8.1. When the pipe is supplied in coils, the minimum internal diameter of the coil shall be as follows:

Nominal size of pipe (mm)

Minimum internal Diameter of coil (cm)

6

110

10

110

12

110

20

110

25

120

32

150

40

180

50

200

Above 50

As agreed to between the manufacturer and the purchaser

Note: The pipes may also be supplied in coils of diameters smaller than those recommended if agreed to between the purchaser and the supplier.  However, the pipes should be recoiled to a larger diameter after these are delivered.

8.1.1. The end of the pipes shall be plugged or covered.

9. Sampling and Criteria for Conformity

9.1. The sampling procedure to be adopted and the criteria for conformity shall be as given in Appendix D.

10. Marking

10.1. Each pipe shall be indelibly marked at intervals of not more than 5 m in colour as indicated in 10.1.1. The marking shall show the following.

(a) Manufacturer’s name trade mark (b) Outside diameter(c) Class of pipe , and(d) Batch number.

10.1.1. The information specified in 10.1 and 10.2 shall be marked in colour as indicated below for different classes of pipes:

10.2. Each pipe may also be marked with the ISI Certification Mark.

Note: The Use of the ISI Certification Mark is governed by the provision 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 assurances 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 future safeguard. 

Class of pipe

Colour

Class 1

Red

Class 2

Blue

Class 3

Green

Class 4

Yellow

Appendix -A

DETERMINATION OF MAXIMUM VOLATILE MATTER IN CARBON BLACK

A-1. Apparatus

A-1.1. Electric Crucibles – Capable of temperature regulation of ± 25 °C at 950 °C and equipped with a thermocouple activated indicating pyrometer.

A-1.2. Platinum Crucibles - 25 x 35 mm

A-1.3. Petri Dish - 75 mm&

A-1.4. Oven - Electrically operated air circulating type, capable of temperature regulation of ± 1°C at 100 °C.

A-1.5. Analytical Balance - Having a sensitivity of 0.1 g

A-1.6. desiccators

A-2.  Procedure

A-2.1. Dry 5 g of the sample in an air oven at 100°C for 2 hours.

A.2.2. Ignite two platinum crucibles in the electric furnace at 950 ± 25 °C for about 30 minutes.  Cool to about 200°C an iron plate and place in the desiccate.  When these attain the room temperature, weigh them to the nearest 0.1. mg.

A.2. 3.  Place 1 g of dried carbon black in the weighed platinum crucible and close by pushing another weighed crucible leaving an air space not more than 2 mm.

A.2.4.  Ignite the crucibles and contents in the electric furnace for exactly 7 minutes at a temperature of 950 ± 20°C.

A.2.5. Remove the crucible assembly to the desecrator, allow to cool to room temperature and weigh to the nearest 0.1mg.

A-.3. Calculation

A-3.1. Calculate the percentage of volatile matter as follows:

Volatile matter =    loss of mass  X 100 percent.

Mass of sample taken

Note: The loss of volatile matter during drying operation is negligible.

Appendix B

DETERMINATION OF TOLUENE EXTRACT OF CARBON BLACK

B.1 . Apparatus

B.1.1. Extraction Thimbles - Double thickness, fat extracted

B.1.2. Soxhlet Apparatus

B.1.3. Shallow Weighing Dish – 50 ml capacity, of borosilicate glass.

B.2. Reagent

B.2.1. Toluene – Sulfur free of AR quality

B.3. Procedure

B.3.1. Place 5 to 8 g of palletized carbon black or 2 to 5 compressed fluffy black in a paper extraction thimble. Insert the thimble into the Soxhlet extractor.  Measure 50 to 60 ml of toluene into the soxhlet flask.

B.3.2. Assemble the Soxhlet apparatus and extract for 22 hours.

B.3.3. Evaporate successive small portions of the extract solution (filtered if necessary) nearly to dryness in the previously cleaned, dried 50 ml shallow glass weighing dish.  Rinse the extraction flask with toluene and add the washings to the weighing to the weighing dish.  Evaporate the combined extracts on a hot – plate to a volume of approximately 5 to 10 ml and finally the dish and contents in an oven at 115°C until dry.

B.3.4. Cool in a desecrator to room temperature and weigh.

B.4. Calculation

B.4.1. Calculate the toluene extract percent, as follows

Toluene extract =       mass of extract      X 100 percent.

Mass of sample

Appendix C

INTERNAL PRESSURE CREEP RUPTURE TESTS

C-1. General

C-1.1. The test shall be carried out not earlier than 24 hours after the pipes have been manufactured.

C.2. Test specimen

C.2.1.  a Specimen of pipe having free length between the end fittings equal to ten times the outside diameter but  neither less than 250 mm not greater than 750 mm shall be taken for testing from each pipe to be tested:

C-3. Apparatus

C.3.1. Equipment which permits the application of a controlled internal hydraulic pressure to the specimen while being immersed in a thermostatically controlled water bath shall be used.

C-D. Procedure

C-4.1. The pipes shall be fitted with locking plugs at both ends in such a way that the axial forces due to the internal pressure are transmitted to the pipe.  The pipe shall remain free to move in longitudinal direction.

C-.4.2. Through a closable opening in one of the locking plugs, the pipe shall be filled with water at ambient temperature.  It shall be put in a water bath at the test temperature (permissible deviation ± 1°C) and kept in the bath for 1 hour to adjust the temperature.

C-4.3. The pressure in the pipe shall then be increased to the test pressure (p) gradually and without shock, preferably within 10 to 30 seconds in the bath whose temperature has been adjusted in accordance with C-.4.2.  the pressure, with a permissible deviation of ± 2.5 percent pressure (p) shall be calculated from the minimum dimensions and values of induced stress given in Table 2 as follows.

P= 2 S

d –s

where,

p = test pressure in Mpa,

s= minimum wall thickness in mm,

2  = induced stress in Mpa , and

d = nominal outside diameter in mm.

C-5. Assessment of results

C.5.1. The specimen when tested as above shall meet the requirements specified in 6.1.   The tests showing within a distance d from the end cap shall be disregarded and the test repeated.

Appendix D

SCALE OF SAMPLING AND CRITERIA FOR CONFORMITY

D-1. Lot

D-1.1. All pipes in a single consignment of the same out side diameter, same wall thickness same length and manufactured essentially under similar conditions of manufacture shall constitute a lot.

D-1.2. For ascertaining the conformity of the material to the requirements this specification, samples shall be tested from each lot separately.

D-2. Visual and Dimensional Requirements

D.2.1. The number of samples to be taken from a lot shall depend on the size of the lot shall be in accordance with table 3.

Table 3 Scale of sampling and permissible number of defectives for visual and dimensional requirements (clauses D-2.1. and  D-2.2.)

No. of pipes in the lot

Sample number

Sample size

Cumulative sample size

Acceptance number

Rejection number

Up to 100

First 

Second

3

3

3

6

0

1

2

2

101 to 300

First

Second

5

5

5

10

0

1

2

2

301 to 500

First

Second

8

8

8

16

0

1

2

2

501 and above

First

second

13

13

13

20

0

1

2

2

D-2.1.1. These pipes shall be selected at random from the lot and in order to ensure randomness of selection, procedures given in IS: 4905-1968* shall be followed.

D-2.2. The number of pipes given for the first sample in Col.3 of Table 3 shall be taken from the lot and examined for visual and dimensional requirements given in 4 and 5 of the specification.  A pipe failing to satisfy any of these requirements shall be considered as defective.  The lot shall be deemed to have satisfied these requirements if the number of defectives found in the first sample is less than or equal to the corresponding acceptance number given in col. 5 of Table 3.  The lot shall be deemed not to have met these requirements, if the number of defectives found in the first sample is greater than or equal to the corresponding rejection number given in col. 6 of Table if however the pounding rejection number given in col. 6 of Table 3 if however, the pounding acceptance and rejection numbers given n col. 5 and 6 of Table 3, the second sample of the size given in col. 3 of Table 3 shall be taken and examined for these requirements.

* Methods for random sampling.

D-2.3. Criterion for Conformity - The lot shall be considered to   have satisfied these requirements if the number of defectives found in the cumulative sample is less than or equal to the corresponding acceptance number given in col.5 of Table 3, otherwise not.

D-3. Reversion test.

D-3.1. The lot having satisfied visual and dimensional requirements shall be tested for reversion.

D-3.1.1. for this purpose, the first sample of three pipes shall be taken from the lot.  The sample pipe failing in the reversion test shall be considered as defective.  If no defective is found in the first sample, the lot shall be deemed to have met the requirements given in the specification for reversion test.  If however, only one defective is found in the first sample, a second sample of three pipes shall be taken from the lot and tested for reversion.

D.3.2. Criterion for Conformity - The lot shall be deemed to have met the specification requirement for reversion given in 6.2 if not more than one defective is found in the simulative sample otherwise not.

D.4. Hydraulic and tensile strength requirements

D.4.1. The lot having the requirements given in D.2.2 and D-3 shall be finally tested for internal pressure creep rupture test specified in 6.1. and tensile strength test specified 6.3.

D.4.1.1.   for this purpose the number of pipes to be taken at random (see D-2.1.1.) from the lot shall be according to table 4.

Table 4 Scale of Sampling for Hydraulic And Tensile Strength Requirements

Number of pipes in the lot

Sample size

up to 100

2

101 to 300

4

301 and above

6

D-4.1.2. The number of pipes selected from the lot according to D.4.1.1 shall be randomly divided into two equal sets.  Each of pipes in the first set shall be tested for internal pressure creep rupture test according to 6.3.

D.4.2. Criterion for conformity - The lot shall be declared as conforming to the requirements of the specification if no failure occurs under D.4.1.2 otherwise not.

Annexure 13-A.9

SPECIFICATIONS FOR PLASTICS PIPE WORK FOR POTABLE WATER SUPPLIES

PART 1 CHOICE OF MATERIALS AND GENERAL RECOMMENDATIONS

(Extract of BIS: 7634 (part-I)-1975)

0.1. The preparation of a code of practice for plastics pipe work for potable water supplies was taken up to make available comparative physical, chemical and mechanical properties of different types of plastic pipes as well as to given guidelines for their selection for different situations arising in practical usage and also to recommend good practices for the installation and jointing and testing of such pipe systems.

0.2. Part I covers choice of material and general recommendations.

0.2.1.   The other parts of the standard are the following.

Part II Laying and jointing polyethylene (PE) pipes

Part III Laying and jointing of unplasticized PVC pipes

0.3.  In the formulation of this standard due weightage has been given to international co-ordination among the standards and practices prevailing in different countries in addition to relating it to the practice in the field in this country.  This has been met by deriving assistance from BIS: CP312(Part1)- 1973 ‘ Code of practice for plastics pipe work (thermoplastics material): Part 1 General principles and choice of material.

0.4.  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.

 * rules for rounding off numerical values (revised)

1.  Scope

1.1. This code (part I ) deals with the selection of plastic pipe systems  for cold water services and general recommendations applicable to all types of plastic pipe systems.

1.2. The code is limited to plastic pipes extruded from thermoplastic materials.  In this code wherever the term ‘polyethylene’ appears singly it refers to both low density and high density polyethylene pipes.

2.  MATERIALS

2.1. The thermoplastic material generally used for plastic pipe system and the relevant Indian standards are listed below:

Material

Relevant Indian Standards

a) Low density polyethylene (LDPE)

IS: 3076-1968*

b) High density polyethylene(HDPE)

IS: 4984-1972 †

c) Un-plasticized PVC

IS: 4985-1968 ‡

2.2. Visual inspection is necessary for major defects before installation

3.  General considerations

3.1. General

3.1.1. Plastic pipes are suitable for conveying water and have certain advantages over metal pipes, such as the resistance to corrosion, light weight toughness, ease of joining, laying and flexibility.

3.1.2. Some of the plastics are to some extend permeable to many to many gases and care is thus required in the selection of material to be used and in siting of pipe work to avoid hazards.

3.1.3. The tensile strength of plastics decreases with increase in temperature and impact strength tends to decrease with decrease in temperature.  Thermoplastics in general deform under prolonged loading however small.  Such a property of thermoplastics is called, cold flow, normally to prevent failure due to cold flow it is advisable not to allow stresses in the pipe due to cold bending   (see part II of this code) therefore prominent thermoformed bends.

* Specifications for low density polyethylene pipes potable water supplies (first revision)

† Specifications for high density polyethylene pipes for potable water supplies (first revision)

‡ Specifications for unplasticized PVC pipes for potable water supplies.

$ Since printed as IS: 7834 in eight parts.

Table 1

Sl.

No.

characteristic

Polyethylene

UPVC

LDPE

HDPE

1

Chemical resistance

Good all round chemical resistance

Good all round chemical resistance

Good chemical resistance

2

Flexibility

Highly flexible; pipes can be coiled

Less flexible than LDPE, still pipes can be coiled

Relatively rigid

3

Tensile strength

Low

Medium

High

4

Impact strength

Not applicable (highly ductile)

Very good

Fair

5

Common jointing method

Insert type joints, compression fittings and threaded joints

Compression welding, flanged joints

Solvent welded joints flanged joints screwed or threaded joints, rubber ring joints

6

application

Internal plumbing of buildings water supplies

Underground water supply lines also for plumbing in buildings flexible water supply connections in buildings river crossings, highly corrosive applications marshy and saline areas

For all applications like water services (except for hot water), highly corrosive applications plumbing in building river crossings marshy and saline areas.

3.3. Locating pipes after laying - Accurate records of laying of plastic pipes are very essential as they cannot be located by conventional electronic pipe locators.  However, copper or galvanized wire can be spiraled around taped to or aid along side the pipe during installation to permit the use of locating device.

3.4. Limitations

3.4.1. In house installations plastic pipes cannot be used for electrical earthing being a non- conductive material

3.4.2. In colder climates plastic pipes cannot be thawed by conventional and electric equipment.

3.4.3. Where pumps are used with plastics, staring and stopping are the occasions when damage any occur.  The water hammer causes compression of the water in the pipe and consequently results in stretching of the pipe and where necessary, presser relief devices should be included in the pipe lines.

3.5. Provision against effect of sunlight – In order to take care of the possible deteriorating effect of direct sunlight or plastic pipes, certain additives, one of which is carbon black or stabilizers are generally incorporated in their manufacture; however it is advisable to take further persecution by burying such pipes or by laying them in ducts wherever possible or otherwise to prevent direct exposure to sunlight.

4.  Hydraulic characteristics

4.1. The extrusion and injection mounding processes of manufacturing plastic pipes and fittings respectively ensure very smooth and generally highly polished bores. The effect of this is to give excellent hydraulic characteristics resulting in low frictional losses and high flow capacities.

4.2. Plastic pipes maintain the flow characteristics throughput their life due to resistance to corrosion.  For calculation of flow rates using the Hazen-Williams equation, a constant ‘C’ of 140 (for dia. Greater than 75 mm) should be used.  The following equation gives approximate values of frictional losses caused by injection moulded plastics fittings

E = F X D

 Where

E = equivalent pipe length in cm.

D = pipe bore in cm, and

F = constant as given below;

Fitting

Value of Constant ‘F’

90° Elbow

21.6

Tee (straight through)

10.8

Tee (through branch)

42.0

Reduced tee (straight through)

21.6

Sweep bend (90°)

10.0

Angle valve

180.0

Globe valve

360.0

5.  Handling and storage

5.1. The detailed precautions in handling and storing plastic pipes are given in the appropriate parts

(see parts II and III) of this code. These is a tendency for plastic pipes to be abused during handling and spare much more than metal pipes and this should be discouraged and proper care taken since plastic pipes are susceptible to damage.

6.  Laying and jointing

6.1. This aspect of work also has its different requirements as compared to metal pipes and needs different techniques and skills.  Details of laying and jointing are given in Part II and part III of this code

7.  Testing of installations

7.1. All pipe work, fittings and appliances shall be inspected and tested hydraulically after the completion of installation.  Before starting any test the system shall be visually inspected to ensure that the recommendation for the correct installation procedure have been complied with and that the pipe line together with appliances, values and fittings are laid in the prescribed manner.  Solvent welded pipe lines should not be pressure tested until at least 24 hours after the last solvent welded joint has been made.

7.2. All control valves shall be positioned open ‘for the duration of the test and open ends temporarily closed with water tight fittings.  The testing pressure should not be less than one and a half times the rated pressure of the pipe under use.

7.3. Pressure should be applied either by hand pump or power driven pump.  Pressure gauges should be correctly positioned and closely observed to ensure that at no time are the test pressures exceeded.  The system should be slowly and carefully filled with water, to avoid surge pressure of water hammer.  Air vents should be open at all high points so that air may be expelled from the system during filling.

7.4. When the system has been fully charged with water and air displaced from the line air vents should be closed and the line initially inspected for seepage at joints and the firmness of support under load.  Pressure then may be applied until the required test pressure is reached (see Note).

Note: Thermoplastic pipes expand under pressure to a greater extern than pipes of asbestos cement or cast iron.  This expansion is due to low modulus of elasticity of the material and results in initial fall of pressure even though there is no leakage for all the four pressure classification of pipes.  The amount of water required to build up a steady test pressure for the plastics pipes is given in Table 2 and table 3 for polyethylene and PVC pipes respectively. The valleys are only approximate to give a guideline as variations occur due to temperature fluctuation and variation in test pressure and wall thickness.  The time taken to build up approximate study pressure is 12 hours.  Without any additional requirement of make up water, the test pressure should not fall more than 0.2 Kf / cm² at the end of one hour test duration.  This extra quantity of water required is normally termed as make up water.

Table 2 Make up water required while testing polyethylene piping

Nominal size  mm

Litre / 100 m line

25

1.1

32

1.6

40

2.6

50

4.0

65

5.9

80

8.5

100

16.4

125

26.9

Table 3 Make up water requirement while PVC piping

Nominal size MM

Litre / 100 m line

50

2.28

75

4.55

100

6.83

125

10.92

150

14.56

180

18.20

200

22.30

7.5. Long lengths of pipes may be tested in convention section of 1 000 to 1,500 m length

8.  Effect on water quality

8.1. For carefully executed installation using properly manufactured plastic pipes, no taste and odder problems should normally be encountered.  The plastic pipes are safe from bacteriological point of view (see o.3. of IS: 3076-1968*, IS: 4984-1972 †, and IS: 4985-1968 ‡ ).  New PVC installations should be flushed with fresh water for a period of about one hour in order to flush out any lead deposits on the inside surface left over from the extrusion process using lead stabilizers.

* Specification for low density polyethylene pipes for potable water supplies (first revision)

† Specification for high density polyethylene pipe for potable water supplies (first revision)

‡ Specification for unplasticized PVC pipes for potable water supplies.

Annexure 13-A.10

SPECIFICATIONS FOR INSTALLATION OF GLASSFIBRE REINFORCED

PLASTIC (GRP) PIPING SYSTEM

(Extract of BIS: 13916-1994)

1.  Scope

1.1. This standard describes procedure of laying GRP piping system installation and includes requirements for trenching, handling jointing, compaction of back filling and post installation hydrostatic test.

1.1.1. This code does not cover installation that requires special attention, techniques and materials like.

(A)  Pipe through rigid walls  (B) Sebaceous piping and(C) Plant or pumping station piping.

Notes:

1.  Pipes fittings and rubber gaskets to be used for installation of piping system as per this code shall conform to the following standards.

a)  The GRP pipes, jointing and fittings shall conform to IS: 12709-1993.

b)  The Rubber gasket shall conform to IS: 5382-1985

2.  Appropriate stiffness class of the GRP Pipes (see IS: 12709-1994) shall be selected to withstand the overburden (deed load) live load and vacuum conditions, if any considering site conditions.

2. References

The following Indian Standards are necessary adjuncts to this standard

IS. No.

Title

5382-1985

Rubber sealing rings for gas mains water mains and sewers (first revision)

12709-1994

Specification for glass –fibre reinforced plastics (GRP) pipes, joints and fittings for use for potable water supply (first revision

2720 (part7)- 1980

Methods of test for soils :part 7 determination of water content dry density relation using light compaction (second revision)

3.  Terminology

3.0. The terms defined in IS: 12709-1994 shall apply in addition to those defined in 3.1 to 3.13 (See  Fig. 1)

3.1. Bedding - Bedding is the sound granular material directly beneath the pipe in the trench bottom.  Bedding includes the basic trench foundation  ‘ e ‘ if required plus especially prepared layer of sand ‘ f ‘ on which pipe will rest

3.2. Coupling area of joint - This is the space inside the socket in which the rubber ring gasket operates.

3.3. Grove - This is a seating made by turning to lodge the rubber ring gasket.  It possesses the section laid down in the design and is machined at one end of each pipe section or in the coupling as the case may be.

3.4. Leading in - This is the initial part of the socket and assists insertion of the rubber ring gasket

3.5.  Pipe zone (B) - It is the trench cross section area from the bottom of the pipe to a minimum of 300 mm above the top of the pipe and is filled with sound granular soil (see 3.12)

3.6. Primary backfill - It means the density of compacted, dry site soil expressed as a percentage of laboratory standards, as determined by the procedure.

3.7. Ring deflection - It means the density of compacted dry site soil expressed as a percentage of laboratory standards, as determined by the procedure.

3.8.  Ring deflection - It means an out of round condition not exceeding 5% of the diameter of a pipe section as a result external loads imposed upon it.

3.9. Rubber ring gasket or packing - This is rubber ring having the section; diameters and hardness specified by the design and forms the hydraulic seal for the pipes.

3.10. Secondary backfill (C) - it is between the pipe, zone and ground level and is filled with properly compacted native soil.

3.11. Socket - In this part of a pipe, the end of the pipe bearing the rubber ring gasket is inserted or it is a coupling with rubbering gaskets as the case may be.

3.12. Sound granular Soil - It shall be crushed rock with a size range of 5 mm to 25 mm, pea gravel or sand.

3.13. Unstable ground - It shall mean native soil which are soft, mushy and unstable to stand vertically when excavated and which can not be expected to provide a firm foundation or side support.

4.  Handling

4.1. Transportation - All pipe sections and fittings shall be supported on timber saddles spaced at 4 m centers with a maximum overhang of 2 m stock height should not general exceed of 2m.  Pipes shall be stepped to the vehicle over the support points using non-metallic pliable straps or ropes only.

4.2. Storing of pipe and fittings

4.2.1. Pipes and fittings with diameters of less than 1 m may be stored directly on sandy soil the ground should be flat and free from sharp projection and stones/rocks bigger than 40 mm in diameter or of other potentially damaging debris.

4.2.2. Pipes with diameters greater than 1 m may be stored on their delivery cradles at a maximum distance of 6 m c/c.

4.2.3. If the surface is not flat or is sloping, then all the pipes shall be checked to prevent rolling.

4.2.4. All rubber rings gaskets and other items shall be stored in a cool, dry and dark place to avoid damage of any kind.

4.2.5. The containers of lubricants should be kept tightly closed to avoid entry of dirt.

4.3. Unloading, lifting and lowering

4.3.0. The following procedures should be followed so as to eliminate potential damage to pipes and fittings and to maintain maximum safety during unloading lighting and lowering.

4.3.1. All the pipes and fittings shall be lifted with pliable straps, slings or ropes.  These may be canvas or polyester belts with a minimum width of 10 cms or nylon ropes with a minimum diameter of 30 mm.  Steel cables or ropes shall not be used for lifting and transportation of pipe.  Foxes shall not pass through the section of the pipe end to end.

4.3.2. Straight continues lengths of pipe may be lifted at one point.  However, owing to its very smooth surface it is usually safer for the pipe to be lifted at two points.

4.3.3. Pipe assemblies fabricated in multiple sections or special places shall be lifted with two or more lifting points.

4.3.4. Pipes shall be dropped to avoid impact or bump.  If any time during handling or during installation any damage, such as gouge, crack or fracture occurs, the pipe shall be repaired if so permitted by the competent authority before installation

4.3.5. Pipes of different diameters may be nested to reduce the transportation cost and space.  Denoting accomplished by starting with smallest size by lifting slightly with an inserted padded beam to suspend and carefully moving it out of the bundle without touching the other pipes.

Note: Stacking of different diameter pipes by nesting however, is not permitted, except in their original transport packing.

5.  Pipe joining

5.0. General - The pipe shall have a jointing system that shall provide for fluid tightness for the interned service conditions.  Section of different pipe jointing system depends upon location, site and working condition, pressure and flow of liquids.

5.1. Unrestrained pipe joint - These pipe joints are capable of withstanding internal pressure but not longitudinal forces.  These joints however can accommodate the liner variation of the pipe due to temperature variation.

5.1.1. Spigot and socket joint with single water tight – rubber ring gasket/packing - This type of joint enables a pipeline to be laid speedily and is suitable for low (up to 3 PN) pressures in burried lines(see Fig 2)

Fig. 2 Illustration of spigot and socket joint with single rubber gasket

5.1.2.   Spigot and socket joint with double watertight rubber ring gasket /packing - This joint is made with double rubber ring and is suitable for high pressure (3 PN and above) (see Fig.3)

Fig. 3 Illustration of spigot and socket joint with double rubber gasket

5.1.3. Double socket coupling joint with watertight rubber gasket / packing - This joint is made with double socket type coupling and is suitable for low and high pressure (see Fig.4)

Fig. 4 Illustration of double socket coupling joint

5.1.3.1. Cleaning, lubrication and installation of rubber ring gasket should be as given in 8.1.7.

5.1.3.2. The pipe to be connected shall be placed in the bed with the sufficient distance from previously joined pipe to allow lowering of pipe with coupling on to the previously laid pipe by means of jack after clamping the pipe.

5.1.3.3. Care shall be taken in the alignment of the coupling with pipes.

5.2. Restrained pipe joint - The restrained type pipe joint is capable of withstanding internal pressure and longitudinal forces.  For pipe line consisting of restrained joints only, expansion joints shall be provided in consummation with the manufacturer of pipe fittings.

Note: Coefficient of thermal expansion for GRP pipes may be taken as 30 X 10 –6 mm/°C.

5.2.1. Spigot and socket joint with gluing - This joint is suitable for underground applications under conditions of normal outside loads and low pressures.  It is easy to make and enables a high laying speed to be reached.  The gluing is to be done by polyester cement or any other adhesive suitable for a hydraulic and mechanical seal (see Fig.5.)

Fig.5 Illustration of spigot and socket joint with gluing

5.2.2. Spigot and socket joint with Glue and overlay - This type of joint is suitable but for low and high pressure (see Fig.6.) Gluing the joint should be done with suitable adhesive and overlay with the same material as used in pipe.  The minimum thickness of overlay shall be 1.5 times of the thickness of pipes

Fig. 6 Illustration of spigot and socket joint with glue and overlay

5.2.3.  Butt joint - It is used for running pipes and for the connection of straight runs to fittings (redirection , elbows, flanges, etc)   The minimum thickness of joint ‘t’ shall not be less than the thickness of pipe width of overlay shall not be less than ten times the thickness of the pipe on wither side of the joint.  The joint is made with hand lay up method (see Fig.7.)

Fig. 7 Illustration of butt joint

5.2.4. Flanged Joint - The flange joint is used for connecting the valves, pumps or any other apparatus or pipes of different materials.  The flanged joint is made from the same material as the pipe (see Fig.8.).

Fig. 8 Illustration of flanged joint

5.2.5. Steel collar on GRP pipes for flanged Connection - A steel loose flange is slipped on to a GRP pipe and then a hand lay up collar is done.  The steel collar may now be connected to any flanged connection (see Fig 9.)

Fig.9. Illustration of steel collar for flanged connection

6. Excavation and preparation of trench

6.1. Trench excavation

6.1.1. Trench Contour - The surface at the trench grade should be continuous smooth and free of big rocks more than 1.5. times the thickness of the pipe if rounded, or more than 1.0 times the  thickness of the pipe if they have sharp edges and may cause point loading on the pipe.  When ledge rock hardpan, big rocks timber or other foreign materials are to be found it is advisable to pad the trench bottom with sand or compacted fine grained soils at least 15 cm thick so as to provide an adequate foundation.

6.1.2.  Trench width, A - The width of the trench at top of the pipe should  not be greater than necessary to provide adequate room for joining the pipe in the treat and for compacting the backfill in the zone of the pipe at the side thereof.  If necessary, bell holes are permissible at the joints.

6.1.3. Trench depth - Trench depth should be determined by the intended service, properties, size the pipe and local conditions such as properties of soil and combination of static and dynamic loading.  It should be ensured that the burial depth is sufficient to prevent the conveyed fluids from being affected by frost penetration.

Local state and other safety regulations/laws should be followed.  If required, necessary measures should be taken to support the trench walls with sufficient strength to protect the employees working in the trench.

6.2. Stable trench conditions - Stable trench conditions occur with soils where only small displacement is caused by variations in pressure (stresses) or moisture content.  Such conditions enable the trench wall to be made vertical from the bed to top of the pipe without the use of shearing or sheet piling (see Fig.10.)  The slope ‘c’ at the top edge of the trench on either sides should be provided to avoid caving in of the top soil and to facilitate smooth installation of the pipeline.

Fig. 10 Illustration in stable soils - Method of trench construction

A = width of the trench

B = Pipe zone area filled with sound granular soil to a minimum of 300 mm above the top of the pipe

C = Secondary backfill having minimum depth as (D= 300) mm to avoid flotation and should be encased appropriately in RCC pipe or with RCC slab when impact load/ vibration of vehicular traffic or otherwise is anticipated

S = Should be as per the following values

Pipe Dia

S mm

200 to 500

200

600 to 900

300

1000 to 1600

450

Above 1600

600

F = Bedding (15mm) minimum

6.3. Unstable trench conditions

6.3.1. This condition exists when the bottom has soft loose, r highly expansive soil.  Unstable soil condition occurs when soil has less than 1 440 kg/m2 of cohesion as calculated from an unconfined compression test. Cohesion for different consistency of soil is given in Table 1 for information.

Table 1 Consistency for Cohesive Soils

Consistency

Cohesion in KG/m2 from unconfined compression test

Very soft

1 220

Soft

1220 – 1440

Medium

1440 – 4880

Stiff

4880 – 9765

Very stiff

9765 – 19530

Hard

19530

6.3.2. The bottom of the trench and its sides must be stabilized before laying pipeline.  This can be accomplished (see Fig.11. and Fig.12.) by lowering the water table at least 25 cm below the elevation of the invert with well points, shoring or sheet piling the sides or by over excavating the borrow and sides of the trench and replacing them with a mixture of sand and coarse gravel or crushed stone or a combination of the above methods.

E= Foundation ( if required ), 15 cm minimum

Note: A,B,C, F and S are as explained in Fig.10

Fig. 11 Method of trench construction for unstable soil conditions - Alternative 1

6.4. Trench denaturing - Ideally the water level should be kept below the pipe invert for the installation to proceed normally.  In conditions when the water level is high the usual and most economical of laying is as follows:

(a)  Open enough trench to lay or two lengths of pipe and then backfill;(b)  Remove the ground water by starting construction at the outlet and placing the pipe upstream water will drain through the pipe in this stream;(c)  If the pipe has to be laid from the inlet down stream the water may have to be pumped to the surface of the ground at the top of the trench for disposal; and (d)  Do not turn the denaturing system until sufficient cover depth has been reached to prevent the pipe floatation.

7.  Bedding, backfilling and compaction

7.1. Bedding

7.1.1. The pipe should be uniformly and continuously supported through its whole length with firm stable bedding material should be sand or gravel as per the requirements on the backfill material (see 3.6.)

7.1.2.  The bedding should be placed so as to give complete contact between the bottom of the trench and the pipe and should be compacted to prove a minimum compaction corresponding to 90% maximum dry density [ see IS: 2720 (part 7) -1980].

7.1.3. If the pipes are supported on grade elevation with use of timber or of tapered wedges, they must be removed and not left in place. They can usually be pulled out a after the bedding has been compacted to the specified minimum compaction.  The voids from which the timber has been removed must be properly filled and compacted. 

7.2. Back filling

7.2.1.  Back filling should be place in layers not exceeding a depth per layer which can be compacted to a minimum of 85% maximum dry density [ See IS: 2720(part 7) -1980].  Light should normally not be greater than 30 cm in height and the height differential on each side of the pipe should be limited to this amount so as to preen lateral movement of the pipe.

7.2.2. Most coarse grained soil are acceptable.  This may comprise of gravel or sand.  However, silts sand, clayey sand, silts and clayey gravel shall not be used unless proposed to be used in conjunction with gravel or clean sand.

7.2.3. It is very important that the pipe size backfill material does not wash away or migrate into the native soil.  Likewise, potential migration of the native soil into the pipe zone backfill must also be prevented.

7.2.4.  Heavy earth moving equipment used for backfilling should not be brought until the minimum cover over the pipe is 90 cm in the case pf wide tracked bulldozers or 120 cm in the case of wheeled roads or roller compactors.

7.3. Compaction - Vibratory methods are preferably for compaction within distances of 15 cm to 45 from the pipe is usually done with had tempers.

8 . Laying of pipe.

8.1.Laying should take place only after the trench and the surface supporting the pipes have been prepared according to this specification.

8.2.  For a coupling type of joint two rubber ring gaskets are first fixed into the groove inside the coupling and then the coupling is to be fixed at the coupling area of the pipe it to be lowered in the trench.

8.3.  Before placing a pipe in the trench it is necessary to clean any remains of earth sand or mud from the inside of the socket and from the opposite end bearing taken place, run a had around inside the socket to ensure that there are no residues of hardened resin which can be removed readily with a chisel.  It is also necessary to checks that the groove has an even depth and has not been damaged for instance during carriage of handling.

Fig. 13 Laying of pipe

8.4. Place the pipe in the trench taking care to dig a small hollow at each end so that the groove and the socket are well separated from the sand and grovels in the bottom of the trench.

8.5. Anchor the first pipe section laid according to the method described and leave its ends free along a space enough for insertion of the next section and for checking.

Place the next pipe section in the trench and leave enough space for the operator to be free to move and to work between the two pipe sections so as to carry out the cleaning and checking operations (see Fig. 13)

8.6. Clean the coupling area of the joint once more with a cloth and also clean the flared portion of the lead – in using suitable lubricant.

8.7. Clean the grove again take the rubber ring gasket and lubricate it by running it between the hands and checking at the same time it being in good condition inside of the socket must not lacks lubricant as ti will impair good insertion of the pipe.

8.8. For socket and spigot type of joint pass the rubber ring under the pipe until it settles into the groove, then pull it forcibly upwards and follow the ring with the hands so that three quarters of it is positioned in the groove, then lift the ring above the upper generating line of the pipe forcibly and then release it so that it falls.  Into the groove thus being greed of any twists.

8.8.1. Run the hands around the pipe to check that the whole of the packing is in its seating and in the case of large diameter pipes smear lubricant again above the inserted rubber ring gasket/packing (see Fig 14)

8.8.2. Align and bring together the two pipe sections until rubber ting touches the flared portion of the lead in. When this has taken place, examine the position of the ring and above all ensure that there are no sand or other foreign bodies present.

8.8.3. Fit the socket onto spigot very slowly dwelling halfway along the coupling area, and check the position of the packing visually.

8.8.4. Proceed with the joint until the socket is halted by the abutment ledge.  The next section should not be fitted until the previous pipe section has been anchored with an overlay of sand.

8.9. Check the rubber ring gasket/packing after the joint has been coupled.  This check must always be carried out and is performed with a blade of steel or of another metal having a thickness of 0.4/0.5 mm, a width of 15 mm and any length greater than 200mm the blade being inserted into the annual space between the socket and the spigot.

This check should be conducted along all the circumference where the packing is compressed so as the ensure that the rubber ring has a homogeneous depth and is therefore correctly positioned in its seating.  If the ring is found to be seated figgerently at one point than other points or if there is any doubt disconnect the joint, check the rubber ring and replace it if it shows any permanent signs of faulty seating, check once more the coupling area of the joint, the flared lead in of the socket and the groove on the spigot, when re-inserting the pipe section, take extra care to align the pipes perfectly.  When uncoupling pipe sections never use chains or steel cables in direct contact with the pipes.

Check once again the position of the ring with the blade.

8.10. Misalignments of the joint - when for reasons of the layout of the line the joint has to be misarranged (but such misalignment must remain within the limits provided by the supplier of the pipes) such misalignment at the predetermined angle should be applied only after having inserted the pipe and the joint is toughly checked for its water tightness (see 9).

8.11. Lowering of pipes - pipes should be lowered in the trench with appropriate mechanical means like chain pulley block, excavators etc.

8.12. Thrust block - RCC thrust block should be provided at bends and at place of reduction in cross section to take care of thrust.

9. Hydrostatic tests.

9.1. Completed pipe in joints shall be hydrostatically. Tested for leakage as given in 9.2 prior to acceptance and service.  It shall be done regularly as installation proceeds.  Installation should never exceed testing by more than 1 km.

9.2. Leak detection testing shall be carried out at a test pressure corresponding to 1.5.times the pressure class of the pipe/fittings.  The test pressure shall be maintained for a period of 24 hours.  Each full length pipe section, fittings and joints shall be leak light.

Annexure 13-A.11

SPECIFICATIONS FOR DIAPHRAGM TYPE (PLASTIC BODY) FLOAT OPERATED VALVES FOR COLD WATER SERVICES  (Extract of BIS: 13049-1991)

1. Scope - This  standard specifies materials, workmanship performance and sampling , requirements besides where appropriate, dimensions and tolerances of diaphragm type float operated valves for water services up to 45°C for use in flush tanks, overhead  water tanks, etc.,

2. References - The following Indian Standards below are necessary adjuncts to this standard

IS No.

Title

2643 (part 3 )-1975

Dimensions for pipe threads for fastening purposes: part 3 Limits of sizes (first revision)

4346-1982

Washers for use with fittings for water services (first revision)

4905-1968

Methods for random sampling

9762-1981

Polyethylene floats for ball valves

3. Definitions

3.0. For the purpose of this standard, the following definitions shall apply.

3.1. Diaphragm type float operated valve – A float operated valve in which the flow of water is controlled by flexing of a diaphragm and which incorporates or is fitted with a discharge arrangement to conduct the water into the cistern.

3.2. Effective warning water level - The level when water reaches 10 mm above the invert of a side or bottom connection warning pipe in a flushing cistern(see Fig.1)

4.  Nominal size - The nominal size of the float valve shall be 15 mm

5.  Materials

5.1. The component/parts shall be made of materials given in Table 1.

5.2. When choosing plastic materials manufacturer shall take due account of the characteristics required for satisfactory use, that is mechanical, dimensional and chemical stability plastic selected shall not degrade under normal working conditions.

5.3. With the exception of valve seats and back plate plungers where no reworked material shall be used, the plastic parts of valves can be manufactured if required with the addition of not more than 15 percent of the manufacturer’s own clean reworked plastic material resulting from the manufacturing process.  No other reworked material shall be used.

All dimensions in millimeters

Fig. 1 Illustration of effective warning water level in relation to other commonly

 defined levels in a flushing cistern

Table 1

Sl. No.

Components / parts

Material

1

Valve body , inlet shank valve seat and back nut

Polyacetal

2

Discharge horn (if provided)

Polyacetal or polypropylene or polyethylene or diene styrene (ABS) or ethylene vinyl Acetate  (EVA) or any other suitable material

3

Diaphragm

Synthetic rubber

6.  Manufacture and workmanship

6.1. Parts shall be sound in all respects and free from defects such as flash, plugging, etc which may arise during manufacture.

6.2. The materials used for manufacturing the parts of the valves when in contact with the water shall not constitute a toxic hazard and any unpleasant taste, odour, Cloudiness and discoloration to the water.

7.  Construction

7.1. Inlet connection - The inlet shank shall be not less than 48 mm in length.  External screw on inlet connections shall be such as to meet the test requirements of Annex. A.

7.2. Seats and body

7.2.1. The valves shall be supplies with a high pressure (HP) or a low pressure (LP) seat

Note: The HP seat is intended for use with water pressure above 0.35 Mpa and up to 1.05 Mpa and the LP seat for water pressure of 0.35 Mpa and below.

7.2.3. The distance between the seat outlet orifice and the shutting off face of the diaphragm shall be 1.5. mm Min in the fully opened position.

7.3. Diaphragm - Diaphragms made of synthetics rubber shall have the form and dimensions as required for the operation of the valve.

7.4. Back nuts - The inlet shank of every valve shall be provided with two back nuts with parallel internal threads conforming to IS: 2643 (part 3)-1975 and of the same size as float valves.  Threads on Back nuts shall also comply with the test requirements of Annex. A.

7.5. Floats float arm and assembly

7.5.1.  Floats should be either blow moulded hollow from polyethylene material or moulded solid from foamed polystyrene material or equivalent water repellent material and shall satisfy the tests specified in 6 of IS: 9762 -1981.

The float shall be watertight and non – absorbing and shall not contaminate water

7.5.2. The design of float arm shall incorporate a positive, readily accessible method of adjustment and locking to set the water level in the cistern.

7.5.3. Float arm and assembly shall be tested in accordance with Annex B. and after the test the initial deflection shall not be more than 25mm.  Additional deflection after loading for 28 days as specified in Annex B shall not be more than 12 mm.  Total deflection thus shall not be more than 37 mm.

7.6. Discharge arrangements

7.6.1. The float valve shall be so constructed as to effectively prevent back – siphonage of water previously discharged at all water levels up to the horizontal center line of the valve, also called the effective water level.

7.6.2. If the discharge point is above the horizontal center line of the valve it shall be at a level high enough to prevent back-siphonage. The construction shall not facilitate the fitting of any pipe or device to conduct water to a lower level.

7.6.3. If the discharge point is below is the horizontal center line of the valve, the discharge arrangements shall incorporate on or more constantly open air inlets or backflow prevention devices.

8.  Performance test

8.1. Hydraulic test - The valve shall be capable of withstanding whilst held in the closed position an internally applied hydraulic pressure of        Mpa for a period of 60 seconds without leaking.

8.2. Shut – off test - When tested in accordance with Annex. C the valve when assembled in working condition but without flow restrictions and fitted with the relevant seat and the float immersed to half its value, shall remain closed against the following minimum test pressure as appropriate:

HP seat – 1.05 Mpa

LP Seat – 0.35 Mpa

8.3. Antisiphonage test - the valve when tester according to Annex. D shall have no back siphonage as indicated by the presence of water in the catch pot.

8.4. Flow test - The valve shall be capable of delivering at least 9 liters of water in 140 seconds into the container when tested in accordance with the requirements of Annex. E.

8.5. Endurance test - The valve when tested in accordance with Annex. F. shall be capable of completing 200 000 cycles and shall then i8mmediately satisfy the hydraulic and shut – off tests specified in 8.1and 8.2.

8.6. Test for hydraulic pressure on discharge arrangements - The valve together with its discharge arrangements shall withstand a constantly applied hydraulic pressure without causing any permanent deformation or separation of any component part when tested in accordance with the method described in Annex. G.

9.  Sampling

9.1. Scale of sampling

9.1.1. Lot -  In any consignment all the float valves of same type made of the same material and produced under similar conditions shall be grouped together to constitute a lot.

9.1.2. For ascertaining the conformity of the material to the requirements of the specification samples shall be tested from each lot separately.

9.1.3.   Number of valves to be selected from a lot shall depend upon the size of the lot and shall be in accordance with col. 1 and 2 of Table 2.

9.1.3.1. The valves from the lot shall be selected at random and in order to ensure the randomness of selection procedures given in IS: 4905-1968 may be followed.

Table  2. Scale of sampling and criteria for Conformity

Lot size

Sample size

Acceptance number

Up to 100

5

0

101 – 150

8

0

151 – 500

13

1

501 – 1000

20

1

1001 – and above

32

2

9.2. Number of test and criteria for conformity

9.2.1. All the valves selected according to col.2 of Table 2 shall be examined for material manufacture and workmanship and construction. Any valve failing in one or more of these requirements shall be considered as defective

9.2.2. The lot shall be considered as conforming to these requirements if the number of defective items found in the sample is less than or equal to the corresponding acceptance number given in col.3 of table 2.

9.2.3. The lot having satisfied the requirements given in 9.2.1 shall be further tested for hydraulic test (8.1), shut – off test (8.2), flow test (8.4) and test for hydraulic pressure on discharge arrangements (8.6) .

9.2.3.1. For this purpose, the number of valves selected in col.2 of table 2 shall be taken.

9.2.4. The lot shall be considered to have satisfied the requirements only if none of the sample fails in the requirements tested for 9.2.3.

9.3. Type Test - One sample each shall be subjected to Antisiphonage test (8.3) and endurance Test (8.4.) at least once in a month.  These tests shall pass.  In case of failure(s) corrective action shall be taken in the manufacturing system and all the performance tests under 8 shall be repeated.

10.  Marking

10.1. Every valve shall be permanently and legibly marked with the following.

(a)  Indication of the source of manufacture(b)  Nominal size – 15 mm,(c)  Class of valve – diaphragm type, and (d)  Whether side or bottom entry(e)  Date of manufacture or lot number

10.2. The valves may also be marked with the standard mark.

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