STEEL & ALUMINIUM WORKS -3



STEEL, IRON AND ALLUMINIUM WORKS

Annexure 7-A.12

CODE OF PRACTICE FOR USE OF STEEL TUBES IN GENERAL BUILDING CONSTRUCTION

1. Scope

1.1. This code deals with the use of structural steel tubes in general building construction and is complementary to IS: 800-1962.  Provisions which are of special application to construction using steel tubes are included in this code. 

2. General

2.1.Unless otherwise specified in this code, provisions of IS: 800-1962 with regard to terminology, plans and drawings, loads and general considerations for the design, fabrication and erection are applicable in the use of steel tubes in general building construction. 

3. Materials

3.1. Steel tubes – Steel tubes used in building construction shall be hot finished tubes conforming to the requirements specified in IS: 1161-1963.

3.1.1.Tubes made by other than hot finishing processes, or which have been subjected to cold working, shall be regarded as hot finished if they have subsequently been heat-treated and are supplied in the normalized conditions.

NOTE: Grade ERW Yst 22 tubes specified in IS: 1161-1963 with carbon content less than 0.30 percent, may be considered as hot finished for the purposes of 3.1.1

3.2. Electrodes – The electrodes used for welding steel tubes shall conform to the requirements of IS: 814-1963†.

4. Wind pressure

4.1. In calculating the effective wind pressure on exposed circular tube members of a structure, the effective area shall be taken as 0.6 times the projected area of the member.   (Refer to IS: 875-1964 ‡ for values of wind pressure). 

5. Permissible stresses

5.0. The provision as regards permissible stresses on the net or gross cross-sectional areas, as the case may be, in 5.1 to 5.8 of this code, is applicable to steel tubes for which the minus tolerance on the weight per unit length of tube is not more than 4 percent.  If on the steel tubes used the minus tolerances on the weight per unit length are larger than 4 percent, a corresponding reduction in cross-sectional areas is required to be made in applying the permissible stresses. 

5.1. Axial stress in tension – The direct stress in axial tension on the net cross-sectional area of tubes shall not exceed the values of Ft given in Table 1.

Table   1 Permissible axial stress in tension

Grade

  Yst  22

  Yst  25

   Yst  32

Ft   kgf/cm2

1 250

1 500

1 900

5.2. Axial stress in compression - The direct stress in compression on the cross-sectional area of axially loaded steel tubes shall not exceed the values of Fc given in Table 2 which l/r is equal to the effective length of the member divided by the radius of gyration.  

Table 2 Permissible axial stress in compression (Clause 5.2)

l/r

Fe

Grade Yst 22 Kgf/cm2

Grade Yst 25 Kgf/cm2

Grade Yst 32 Kgf/cm2

0

1250

1500

1900

10

1217

1448

1821

20

1175

1400

1750

30

1131

1352

1679

40

1088

1303

1610

50

1046

1255

1539

60

1002

1207

1468

70

970

1155

1375

80

929

1088

1263

90

876

1003

1128

100

814

910

989

110

745

813

869

120

674

721

758

130

603

638

665

140

540

`565

584

150

490

503

517

160

432

443

450

170

381

392

398

180

339

348

353

190

304

311

315

200

271

278

280

210

243

249

250

220

219

225

227

230

198

204

205

240

180

185

187

250

162

167

167

300

106

106

106

350

71

71

72

Note: 1 – Intermediate values may be obtained by linear interpolation.

Note: 2 – The formula, from which these values have been derived, is given in Appendix A.

5.3. Bending stresses – In tubes, the tensile bending stress and the compressive bending in the extreme fibres shall not exceed the values of Fb given in Table 3.

Table 3. Permissible bending stress in extreme fibres in tension and compression (Clause 5.3)

GRADE 

Yst  22

Yst  25

Yst  32

Fb   kgf/cm2

1 400

1 655

2 050

 5.4. Shear stress – The maximum shear stress in a tube calculated by dividing the total shear by an area equal to half the net cross-sectional area of the tube shall not exceed the values of Fs given in Table 4.  The net cross-sectional area shall be derived by deducting areas of all holes from the gross cross-sectional area. 

Table 4  Permissible maximum shear stress

GRADE

 Yst  22

 Yst  25

 Yst  32

Fs kgf/cm2

900

1 100

1 350

5.5. Bearing stress The average bearing stress on the net projected area of contact shall not exceed the values of Fp given in Table5

Table 5  Permissible maximum bearing stress

GRADE

 Yst  22

Yst  25

Yst  32

Fp   kgf/cm2

1 700

1 900

2 500

5.6. Combined bending and axial stress - Members subject to both bending and axial stresses shall be so proportioned that the quantity :

 fa               fb

------   +   -----    does not exceed unity,

 Fa            Fb     

Where fa  = Calculated axial stress, that is, axial load divided by appropriate area of member;

Fa = Permissible stress in member for axial load;

fb = Calculated bending stress in the extreme fibre; and

Fb = Permissible bending stress in the extreme fibre.

5.6.1 When bending occurs about both axes of the member, fb shall be taken as:

               ______________

fb =    V    (fbx)2  +  (fby)2 

Where fbx and fby are the calculated unit fibre stresses. 

5.7. Permissible stresses in welds

5.7.1. Butt welds – The stress in a butt weld shall be calculated on an area equal to the effective throat thickness multiplied by the effective length of the weld measured at the centre of its thickness.  In a butt weld the allowable tensile, compressive and shear stresses shall not exceed the stresses respectively permissible in Yst 25 tubes or in the parent metal, whichever is less.

5.7.2. Fillet welds and fillet butt welds – [see 6.7.3.2 (c)]The stress in a fillet weld or a fillet-butt weld shall be calculated on an area equal to the minimum effective throat thickness multiplied by the length of the weld.  A method of calculating the length of the weld is given in Appendix B.  In a fillet

weld or in a fillet-butt weld, the permissible stress shall not exceed the shear stress permissible in Yst 25 tubes or in the parent metal, whichever is less.

5.7.2.1. Combined stresses in a fillet or fillet-butt weld – When the fillet welds in a connection are subjected to the action of bending combined with direct load, the maximum resultant stress shall be calculated as the vector sum, and shall not exceed the permissible stress as specified in 5.7.2.

5.8. Increase of stresses

5.8.1. Increase of permissible stresses for occasional loads may be allowed according to the provisions of IS: 800 – 1962*.

5.8.2. Irrespective of any permissible increase of allowable stress, the equivalent stress, ¦e due to co-existent bending and shear stresses shall not exceed the values given in Table 6.

Table 6 Maximum allowable equivalent stress

GRADE

Yst  22

Yst  25

Yst  32

Fe   kgf/cm2

1 900

2 285

2 900

5.8.2.1. The equivalent stress ¦e is obtained from the following formula:

             ___________

feV  fb2 + 3 fs2        

Where

fb = the calculated bending stresses (compression or tension) at the point under consideration, and

fs = the calculated actual co-existent shear stress at the point under consideration.

6. Design

6.1. General - The principles and procedures of design contained in Section IV of IS: 800 – 1962 generally applicable to structures using steel tubes.

6.2. Basis of design – The basic methods of design for structures using steel tubes generally similar to those for other types of elastic structures.  Welding is generally adopted for connections in tubular steel construction.  Since the connections in such cases given rigid joints, it is desirable to design such welded structures taking into consideration the actual condition of rigidity particularly since such design results in saving in materials and greater overall economy.  For structures designed on the basis of fixity of connections, a full account is to be taken of the effects of such fixity. 

6.2.1 Structural frameworks using steel tubes including those with welded connections may, however, be designed on a simple design basis, comparable with that given in IS: 800-1962.   In such cases, secondary stresses may be neglected in the design of trussed girders or roof trusses, except where the axes of the members do not meet at a point.  Where there is such eccentricity, the effects of the eccentricity should also be considered. 

6.2.2. Curved members and bends - The design of curved members and bends shall be given special considerations, and allowance shall be made for any thinning of the bent part which may be caused by bending the member. 

6.3. Minimum thickness of metals

6.3.1. For tubular steelwork painted with one priming coat of red oxide zinc chromate paint after fabrication and periodically painted and maintained regularly, wall thickness of tubes used for construction exposed to weather shall be not less than 4 mm, and for construction not exposed to weather it shall be not less than 3.2 mm; where structures are not readily accessible for maintenance, the minimum thickness shall be 5 mm. 

6.3.2. Steel tubes used for construction exposed to weather shall be not less than 3.2 mm thick and for construction not exposed to weather shall not less than 2.6 mm thick, provided in each case the tube is applied with :(a)one coat of zinc primer conforming to IS: 104 – 1962 followed by a coat of paint conforming to IS : 2074 – 1962 †, and  (b) two coats of paint conforming to IS: 123 – 1962 . This painting system should be renewed after every two years in the case of tubes exposed to weather.  In case some other metallic corrosion protecting material is used, such as aluminium painting, the renewal of coating may be done after longer intervals.

6.4. Compression members

6.4.1. Effective length of compression members – Effective length (l) of compression member for the purpose of determining allowable axial stresses shall be assumed in accordance with Table 7, where L is the actual length of the strut, measured between the centres of lateral supports.  In the case of a compression member provided with a cap or base, the point of lateral support at the end shall be assumed to be in the plane of the top of the cap or bottom of the base. 

Table 7   Effective length of compression members

Type

Effective Length

Effectively held in position and restrained in direction at both ends

0.67   L

Effectively held in position at both ends and restrained in direction at one end.

0.85   L

Effectively held in position at both ends but not restrained in direction

L

Effectively held in position and restrained in direction at one end, and at the other end effectively  restrained in direction but not held in position

L

Effectively held in position and restrained in direction at one end, and at the other end partially restrained in direction but not held in position

1.5 L

Effectively held in position and restrained in direction at one end  but not held in position or restrained in direction at the other end

2.0 L

6.4.1.1. Members of trusses - In the case of bolted, riveted or welded trusses and braced frames, the effective length (l) of the compression members shall be taken as between 0.7 and 1.0 times the distance between centres of intersections, depending on the degree of end restrained provided.

6.4.2. Maximum slenderness ratio of compression members – The ratio of effective length (l) to the appropriate radius of gyration (r) of a compression member shall not exceed the following:

 

Type of Member

l/r

a

Carrying loads resulting from dead loads and superimposed loads

180

b

Carrying loads resulting from wind or seismic forces only, provided the deformation of such members does not adversely, affect the stress in any part of the structure.

250

c

Normally acting as a tie in a roof truss but subject to possible reversal of stress resulting from the action of wind 

350

6.4.3. Eccentricity of beam reactions on columns - For the purpose of determining the eccentricity of beam reactions or similar loads on a column in simple design procedure, the load shall be assumed to be applied as given in Table 8.

Table 8  Assumed eccentricity of loads in columns

Sl.No

Type of connection

Assumed point of application

i

Stiffed bracket

Mid-point of stiffened seating

ii

Unstiffened bracket

Outer face of vertical leg of bracket

iii

Cleats on tube

Outside of tube

iv

Cap :

 

 

a) Beams of approximately equal span and load, continuous over the cap

Mid-point of cap

 

b) Other beams

Edge of stanchion towards of beam except for roof truss bearings

 

c) Roof truss bearings

No eccentricity for simple bearing without connections capable of developing an appreciable moment

6.4.4. Joints

6.4.4.1.  Where in joints in compression members, the ends of the members are faced for bearing over their whole area, the welding and joining material shall be sufficient to retain the members accurately in place and to resist all forces other than direct compression, including those arising during transit, unloading and erection. 

6.4.4.2. Where such members are not faced for complete bearing, the welding and joining material shall be sufficient to transmit all the forces to which the joint is subjected. 

6.4.4.3. Wherever possible, joints shall be proportioned and arranged so that gravity axes of the members and the joints are in line, so as to avoid eccentricity. 

6.4.5. Column bases

6.4.5.1. Gusseted bases

For columns with gusseted bases the gussets and the welds connecting them to the shaft shall be designed to carry the load and bending moment transmitted to them by the base plate.

Where the end of the column shaft and the gusset plates are faced for bearing over their whole area, the welds connecting them to the base plate should be sufficient to retain the parts securely in place and to resist all forces other than direct compression, including those arising during transit, unloading and erection. 

Where the end of the column shaft and the gusset plates are not faced for complete bearing, the welds connecting them to the base plate shall be sufficient to transmit all the forces to which the base is subjected. 

6.4.5.2.Slab bases – For columns with slab bases where the end of the shaft is faced for bearing over its whole area, the welds connecting it to the based plate should be sufficient to retain the parts in place and to resist all forces other than direct compression including those arising during transit, unloading and erection.  (For the design of slab bases see 19.8.2 of IS: 800-1962*).

6.4.6. Latticing and battening of compression members

6.4.6.1.Latticing and battening where necessary shall be proportioned according to the appropriate clauses of IS: 800-1962.

6.4.6.2. Whenever possible, lattices and battens shall be so arranged that their gravity axes are in line with gravity axes of the main members to which they are connected. 

6.5. Design of beams

6.5.1. The tensile and compressive stresses in the extreme fibres of tubes in bending shall not exceed the values prescribed under 5.3.

6.5.2. The maximum shear stress in tubes in flexure, calculated by dividing the total shear by an area equal to half to the net cross-sectional area of the tube, shall not exceed the values prescribed under 5.4.

6.5.3. Stiffeners for tubes - Where the tubular steel beam rests on abutment or other supporting member, it shall be provided with a shoe adequate to transmit the load to the abutment and to stiffen the end of the tube. 

6.5.3.1. Where a concentrated load is applied to a tubular member transverse to its length or the effect of load concentration is given by the intersection of triangular truss members, consideration shall be given to the local stresses set up and the method of application of the load, and stiffening shall be provided as necessary to prevent the local stresses from being excessive. The increase in the intensity of local bending stresses caused by concentrated loads is particularly marked if either the diameter of connected member or the connected length of a gusset or the like is small in relation to the diameter of the tubular member to which is  connected.

6.5.4. Limiting deflections of beams - The deflection of a member shall not be such as to impair the strength, efficiency or appearance of the structure or lead to damage to fittings and finishing. 

Generally, the maximum deflection should not exceed 1/325 of the span for simply supported members. 

6.5.4.1. Purlins

The requirements under 6.5.4 regarding limiting deflection may be waived in the design of simple tubular purlins provided that the following requirements are satisfied :

NATURE OF END FIXING   MINIMUM VALUE OF SECTION
MODULUS     
MINIMUM OUTSIDE DIAMETER FOR GRADES
Grade Grade Grade Yst 22
Yst 22   Yst  25 Yst  32 YSt  25 and
Cm3  cm3 cm3  Yst 32 Cm

Simply supported   -   WL/11 200     WL/13 230 WL/16 400    L/40           

Effectively           -   WL/16,800    WL/19 840      WL/24 600   L/70

Continuous

Where

W = the total distributed load in kg on the purlins arising from dead load and snow but excluding wind, and

L = the distance in cm between the centres of the steel principals or other supports. 

A purlin shall be considered as effectively continuous at any intermediate point of support if it is actually continuous over that point or if it has there a joint able to provide a fixing moment of not less than WL/12, where W and L are as defined above. 

6.6. Separators and diaphragms – When loads are required to be carried from one tube to another or are required to be distributed between tubes, diaphragms which may be tubular, designed with sufficient stiffness to distribute the load between the tubes, shall be used.

6.7. Connections

6.7.1. General – Connections in structures using steel tubes shall be provide by welding, riveting or bolting.  Wherever possible, connections between tubes shall be made directly tube to tube without gusset plates and other attachments.  Ends of tubes may be flattened as specified in 7.7 or otherwise formed to provide for welded, riveted or bolted connections. 

6.7.2. Eccentricity of members – Tubes meeting at a point shall, wherever practicable, have their gravity axes meeting at a point so as to avoid eccentricity. 

6.7.2.1. Eccentricity of connections - Wherever practicable, the centre of resistance of the connection shall lie on the line of action of the load so as to avoid eccentricity moment of the connection. 

6.7.3. Welded connections

6.7.3.1 A weld connecting two tubes end to end shall be full penetration butt weld.  The effective throat thickness of the weld shall be taken as the thickness of the thinner part joined. 

6.7.3.2 A weld connecting the end of one tube (branch tube) to the surface of another tube ( main tube) with their axes at an angle of not less than 30° shall be of the following types :

(a)A butt weld throughout, (b)A fillet weld throughout, and  (c)A fillet-butt weld, the weld being a fillet weld in one part and a butt weld in another with a continuous change from the one form to the other in the intervening portions. 

Type (a) may be used whatever the ratio of the diameters of the tubes joined, provided complete penetration is secured either by the use of backing material, or by depositing a sealing run of metal on the back of the joint, or by some special method of welding.  When type (a) is not employed type (b) should be used where the diameter of the branch tube is less than one-third of the diameter of the main tube, and type (c) should be used where the diameter of the branch tube is equal to or greater than one-third of the diameter of the main tube. 

For the purpose of stress calculation, the throat thickness of the butt weld portion shall be taken as the thickness of the thinner part joined, and the throat thickness of the fillet weld and the fillet-butt weld shall be taken as the minimum effective throat thickness of the fillet of fillet butt weld. 

6.7.3.3. Angle between tubes – A weld connecting the end of one tube to the surface of another, with the axes of the tubes intersecting at an angle of less than 30° , shall be permitted only if adequate efficiency of the junction has been demonstrated. 

6.7.3.4. Connections where the axes of the two tubes do not intersect – A weld connecting the end of one tube to the surface of another where the axes of the two tubes do not intersect, shall be subject to the provisions under 5.7, 6.7.3.2 and 6.7.3.3, provided that no part of the curve of intersection of the eccentric tube with the main tube lies outside the curve of intersection of the corresponding largest permissible non-eccentric tube with the main tube (see Fig.1).

6.7.3.5. Connections of tubes with flattened ends – Where the end of the branch tube is flattened to an elliptical shape 5.7, 6.7.3.2 to 6.7.3.4 shall apply, and for the application of 6.7.3.2 and 6.7.3.4 the diameter of the flattened tube shall be measured in a plane perpendicular to the axis of the main tube. 

7. Fabrication

7.1. General

7.1.1. The general provisions in Section V of IS: 800-1962 are also applicable to the fabrication of structures using steel tubes.  Where welding is adopted, reference to appropriate provision of IS: 820-† (see Note) and IS: 816-1956 shall be made. 

Note - Until this standard is published, provisions for welding in tubular construction shall be as agreed to between the concerned parties. 

7.1.2.  The component parts of the structure shall be assembled in such a manner that they are neither twisted not otherwise damaged and be so prepared that the specified cambers, if any, are maintained. 

Straightening – All material before being assembled shall be straightened, if necessary, unless required to be of a curvilinear form and shall be free from twist.

7.3.1. Washers shall be specially shaped where necessary, or other means used, to give the nuts and the heads of bolts a satisfactory bearing.

7.3.2. In all cases where the full bearing area of the bolt is to be developed, the threaded portion of the bolt shall not be within the thickness of the parts bolted together, and washers of appropriate thickness shall be provided to allow the nut to be completely tightened. 

7.4. Cut edges – Edges should be dressed to a neat and workmanlike finish and be free from distortion where parts are to be in contact metal-to-metal.

7.5. Caps and bases for columns – The ends of all tubes for columns, transmitting loads through the ends, should be true and square to the axis of the tube and should be provided with a cap or base accurately fitted to the end of the tube and screwed, welded or shrunk on.

7.5.1. The cap or base plate should be true and square to the axis of the column. 

7.6 Sealing of tubes – When the end of a tube is not automatically sealed by virtue of its connection by welding to another member, the end shall be properly and completely sealed.

7.6.1. Before sealing, the inside of the tube should be dry and free from loose scale.

7.7. Flattened ends – In tubular construction, the ends of tubes may be flattened or otherwise formed to provide for welded, riveted or bolted connections provided that the methods adopted for such flattening do not injure the material.  The change of section shall be gradual. 

7.8. Oiling and painting – If not galvanized, all tubes shall, unless otherwise specified, be painted or oiled or otherwise protectively coated before exposure to the weather.  If they are to be painted in accordance with any special requirements, this shall be arranged between the purchaser and the manufacturer. 

7.9. Marking, shop erection and packing – Appropriate provisions of IS: 800-1962* shall apply.

8. Inspection and testing

8.1. Appropriate provisions of IS: 800-1962 shall apply.

Annexure 7-A.13

SPECIFICATIONS FOR STRUCTURAL STEEL (ORDINARY QUALITY)

(Extract of IS: 1977-1975)

1. Scope – Requirements for two grades of mild steel (ordinary quality) designated as Fe 310-0 (St 32-0) and Fe 410-0 (St 42-0).  The former grade is intended for general engineering purposes such as door and window frames, window bars, grills, gates, hand railings, builders’ hardware, etc, while latter is intended for use on structures not subjected to dynamic loading other than wind loads, such as platform roofs, foot over bridges, office buildings, etc. 

2. Chemical composition

Steel Designation    Constituents, percent, max
  Carbon Sulphur Phosphorus

Fe 310–0            (St 32–0)  

0.30 0.070 0.070

Fe 410–0           (St 42–0)

0.30 0.070 0.070

Note – Copper may be present up to a maximum of 0.35 percent.

3. Freedom from defects – Finished material shall be reasonably free from cracks, surface flaws, laminations, rough, jagged and imperfect edges, etc.  Minor surface defects may be removed by grinding provided the thickness is not reduced locally by more than 4 percent ( with a maximum of 3 mm). 

4. Mechanical properties

4.1. Tensile test

4.2. Bend test – Shall withstand without fracture the prescribed test when doubled over until internal diameter is not greater than 3 times the thickness of test piece ( 2 times  in case of bars up to 25 mm diameter).

5. Dimensions and Tolerances – Dimensions of rolled steel products shall conform to the relevant Indian Standards as listed in Table 2 of the Standard Rolling and cutting tolerances shall conform the IS: 1852 – 1973*.

6. Weight – Calculated on the basis that steel weighs 7.85 g/cm3.

Steel Designation

Product

Thickness / Diameter

Tensile strength Min. (Kgf /mm2)

Yield strength percent (Kgf / mm2

Elongation Min.

Fe 310-0

Plates, angles, flats, Tees, beams etc.

Below 6 6 and above

Bend test only shall be required       

32 to 4     -      26

 

Bars

Below 10 10 and above

Bend test only shall be required       

32 to 44    -      26

 

Fe 410-0

Plates, flats, angles, Tees, channels, Beams

Below 6 6 upto 20

Over 20 upto 40

Over 40

Bend test only shall be required

42 to 54      26       23

42 to 54      24       23

42 to 54      23       23

 

Bars

Below 10

10 upto 20

Over 20

Bend test only shall be required

42 to 54      26       23

42 to 54      24       23

Note: 1. 1 N /mm2 = 1 MN / m2 = 0.102 kgf/m2

Note: 2 Provided that the yield stress and elongation requirements are compiled with the upper limit for tensile strength may be raised by 3 kgf/mm2

Note: For test procedures, refer to IS:1608-1972 Method of tensile testing of steel products (first revision).  IS: 1599-1974 Method of bend test for steel products other than sheet, strip, wire and tube (first revision), 7, 8 and Appendix A of the standard.

Annexure 7–A.14

SPECIFICATIONS FOR EXPANDED METAL STEEL SHEETS FOR GENERAL PURPOSES

(Extract of IS: 412-1975)

1. Scope - Requirements for expanded metal steel used for general purposes.

2. Size of mesh – Based on measurements of short way of mesh (SWM) and long way of mesh (LWM) of the diamond, and width and thickness of the strands. 

3. Dimensions

Ref.  No.

Size of Mesh  (Nominal)

Largest Standard Size of Sheets

Size of sheet Normally Stocked

SWM (mm)

LWM (mm)

LWM (mm)

SWM (mm)

MM

1

2

3

4

5

6

7

8

9

10

100

100

100

75

75

75

40

40

40

 40

250

250

250

200

200

200

115

115

75

 75

3.75

3.75

3.7`5

3.75

3.75

3.75

2.50

2.50

2.50

2.50

10.97

14.63

21.94

7.30

7.30

14.60

3.75

4.85

4.85

 7.30

 

 

 

2.50 x 3.75

11

12

13

14

40

40

40

40

115

75

115

75

2.50

3.75

2.50

3.75

 7.30

7.30

7.30

7.30

2.50 x 3.75

&

1.25 x 3.75

15

25

75

             2.50

             4.85

2.50 x 3.75

16

17

18

25

25

25

25

25

25

75

75

75

 2.50

2.50

2.50

       2.50 x 3.75   

&

1.25 x 3.75

19

20

20

20

60

50

 2.50

3.75

3.75

3.75

2.50 x 3.75

21

22

23

24

25

26

20

20

20

20

20

20

60

50

60

50

60

50

2.50

3.75

2.50

3.75

2.50

3.75

 3.75

3.75

3.75

3.75

4.85

3.75

 

2.50 x 3.75

&

1.25 x 3.75

27

28

29

30

31

32

33

12.5

12.5

12.5

12.5

12.5

12.5

12.5

50

40

50

50

40

50

40

 2.50

3.75

2.50

2.50

3.75

2.50

3.75

3.00

3.00

3.00

3.00

3.00

3.00

3.00

 

2.50 x 2.75

&

1.25 x 2.75

 

34

35

36

37

38

10

10

10

9.5

9.5

40

40

40

28.5

28.5

2.50

2.50

2.50

2.50

2.50

2.00

2.00

2.00

2.00

2.00

2.50 x 1.75

&

1.25 x 1.75

39

40

41

42

9.5

6

6

6

28.5

25

25

25

2.50

2.50

2.50

2.50

2.00

2.00

2.00

2.00

2.50 x 1.75

&

1.25 x 1.75

43

44

5

3

20

15

2.50

2.50

1.50

1.50

2.50 x 1.25

4. Tolerances

On nominal specified dimension: ± 10 mm

On minimum specified dimension : + 10

                                                          - 0 mm

On mass ± 10 percent (steel weighs 7 650 kg/m)

Size of mesh:

On SWM   ± 1mm up to 20 mm &

                    ± 2 mm over 20 mm

On LWM   ± 2 mm up to 60 mm &

                   ± 4 mm over 60 mm

5. Mechanical properties

5.1.Tensile strength of blank steel sheets shall be between 280 and 380 MN/m2.

Note:1  N/mm2 = 1 MN/m2 = 0.102 kgf/mm2.

5.2. Bend test – Test piece shall withstand without crack, being doubled over when cold, till the internal radius is not grater than 1.5 times its thickness and until the two sides of test piece are parallel. 

6. Freedom from defects Finished expanded metal sheets shall be free form flaws, joints, welds, broken strands, laminations, etc.

7. Preservative treatment – Shall be given a suitable protective coating to prevent corrosion.

Note 1: For test procedures, refer to IS: 1663 – 1972 Method for tensile testing of steel and strip of thickness 0.5 mm to 3 mm ( first revision), and IS : 1692 – 1974 Method for simple bend testing of steel sheet and strip less than 3 mm thick  ( first revision).

Note 2: For chemical composition, see 3.1 and 3.2 of the standard.

Annexure 7-A.15

SPECIFICATIONS FOR STEEL TUBES FOR STRUCTURAL PURPOSES

(Extract of IS:  1161-1979)

1. Scope – Requirements for hot finished welded (HFW), hot finished seamless (HFS), and electric resistance welded (ERW) or induction welded plain carbon steel tubes for structural purposes. 

2. Designation – Designated by their nominal bore and classified as ‘Light’, ‘Medium’ and ‘Heavy’ depending on wall thickness.  They are further graded as Yst 210, Yst 240 and Yst 310 depending on the yield stress. 

3. Dimensions ( in mm )

Nominal  Bore Ouside Diameter Thickness
    Light Medium Heavy 
15 21.3 2.00 2.65 3.25
20 26.9 2.35 2.65 3.25
25 33.7 2.65 3.25 4.05
32 42.4 2.65 3.25 4.05
40 48.3 2.90 3.25 4.05
50 60.3 2.9/3.25 3.65 4.50
65 76.1 3.25 3.65 4.50
80 88.9 3.25 4.05 4.85
90 101.6 3.65 4.05 4.85
100 114.3 3.65 4.50 5.40
110 127.0 4.50 4.85 5.40
125 139.7 4.50 4.85 5.40
135 152.4 4.50 4.85 5.40
150 165.1 4.50 4.85 5.40
175 193.7 4.85 5.40 5.90
200 219.1 4.85 5.60 5.90
225 244.5     5.90
250 273.0     5.90
300 323.9     6.30
350 355.6     8.00

Note: For detailed information regarding weight, area of cross section, moment of inertia, modulus of section, radius gyration, etc. see Table 1 of the standard.

4.Tolerances –

a. Outside diameter :

Up to and including 48.3 mm  : + 0.4 mm

                                                  : – 0.8 mm

Over 48.3 mm : ±  1.0 percent

b. Thickness  ( all sizes) :

Welded tubes :+  Not limited

– 10 percent

* Not limited

– 12.5 percent

5. Workmanship – Tubes shall be free from scale, cracks, surface flows, laminations, etc.

6. Test – For mechanical tests (tensile test. Flattening test, retest, etc), refer to 10 of the standard.

Annexure 7 – A .16

SPECIFICATIONS FOR STEEL TUBES USED FOR WATER WELLS

(Extract of IS: 4270-1967)

1. Scope - Requirements for steel tubes for water wells, such as casing, drive pipe and housing having following types of joints :

(a)Screwed and socketed butt joints,(b)Screwed flush butt joints,(c)Plain bevelled end pipes for butt welded joints, and(d)Slip socket welded joints.

2. Types

(a)Hot finished seamless ( HFS ) (b)Hydraulic lap welded (HLW) (c)Electric automatic fusion welded (EFW) (d)Electric arc welded (EAW) (e) Electric resistance welded (ERW) (f) High frequency induction welded (HFIW)

3. Dimensions ( in mm)

Nominal Size Outside Dia Thickness
    Screwed and Socketed Pipe Casing for Screwed Flush butt Joints Casing for Flush Plain end pipes
100 114.3 6.3 9.5 -
150 168.9 8.0 9.5 -
200 219.1 8.0 11.0 -
250 273.0 9.5 11.0 -
300 323.9 9.5 11.0 9.5
350 355.6 - - 9.5
400 406.4 - 12.7 9.5
450 457.2 - - 9.5
500 508.0 - 12.7 9.5
550 558.8 - - 9.5

Note 1: In respect of casing for slip socket welded joints, same particulars as for casing for plain end pipes shall apply.

Note 2: For details regarding sockets and weights of pipes see 6 of the standard.

4.Tolerances

a. Outside dia - ± 1 percent ( 3 mm Max for socket )

b. Thickness, seamless tube -  + 15  percent

                                                    - 12.5

c. Welded tube :

Up to 406.4 mm outside dia -  + 15 percent

                                                   - 12.5

Over 406.4  mm outside dia - + 15 percent

                                                   - 10

5. Requirements

5.1. Screwed and socket butt joints shall have right-handed V-form threads. There shall not be more than six incomplete external threads. Threads in the socket shall be continuous. 

Screwed flush butt joints shall have right-handed square form threads.

Plain-end pipes shall be supplied with both ends bevelled or both ends square cut or one end bevelled and one end square cut. 

6. Mechanical properties

6.1.Tensile test

Type

Grade

Tensile Strength Min (kgf/mm2)

Yield Strength Min (kgf/mm2)

 

Elongation Percent Min

 

HFS

St 55

55

31.5

950/TS*

HFS, HLW,

EFW, EAW, ERW and HFIW

St 42

42

25

950/TS*

 

* TS = Tensile strength in kgf/mm2.

Flattening test – Shall withstand the prescribed test.

Alignment test – Not more than 20 mm in 6 m length  

Hydraulic pressure test – Shall withstand test pressure of 2800 t/D kgf/cm2 for St 42 and 3500 t/D kgf/cm2 for St 55 subject to a maximum of 70 kgf/cm2 ( t = thickness in mm and D = outside dia in mm).

Coating of tubes – Shall be coated with bituminous solution inside and outside.

Protection of ends

All threads shall be coated with a petroleum jelly or other suitable rust preventing compound.

Tubes with V-form and square form threads shall have the exposed male threads protected with steel rings or sleeves.  Female threads shall be protected with steel nipples or bushes.

For slip joint-casing, wooden protectors should be provided. 

Note: For test procedures, refer to IS: 1894 – 1972 Method of for tensile of steel tubes (first revision) and IS: 2328 – 1963 Method for flattening test on steel tubes.

Annexure 7–A.17

SPECIFICATIONS FOR CORRUGATED ALUMINIUM SHEET 

(Extract of IS: 1254-1975)

1. Scope - Specifies the material, profile, dimensions and finish for corrugated aluminium sheet and covers requirements for

(a)General purpose sheet,  (b) Industrial sheet, and  (c ) Building sheet.

2. Material – Shall be made from sheets in alloy and temper conforming to Alloy 31000 – H4, 31500 – H4, 40800 – H4 or 51300 – H4 of IS: 737-1974.

3. Profile

General Purpose Sheet

Pitch: 75 mm

Depth: 19 mm

3.2. Industrial sheet

Pitch:  125 mm

Depth:  38 mm

3.3. Building sheet

Pitch:  190 mm

Depth:   38 mm

4. Dimensions

4.1. Thickness - As mutually agreed.

4.2. Width

General Purpose : 650 and 800 mm overall , Industrial :795 mm overall,  Building  : 830 mm overall

4.2.1. Tolerance - ± 10 mm for sheets 0.45 mm and above in thickness.  For sheets less than 0.45 mm thick, tolerance shall be as mutually agreed.

4.3. Length – 1 800, 2 400, 3 000 and 3 600 mm.

Tolerance - ± 6 mm.

4.4. Squareness – Diagonal distances of a sheet shall not differ by more than 20 mm for sheets 0.45 mm and above in thickness.  For sheets less than 0.45 mm thick, it shall be as be mutually agreed.

4.5. Finish – As rolled.

Note: For types of profile see 4 of the standard.

Annexure 7–A .18

SPECIFICATIONS FOR HOLLOW STEEL SECTIONS FOR STRUCTURAL USE

(Extract of IS: 4923-1968)

1. Scope – Requirements for hot and cold formed square and rectangular hollow steel sections for structural use.

2. Designation – Hollow section shall be designated by its outside dimensions, and its thickness in millimetre and shall be further classified in CFRHS or HFRHS depending on whether it is cold or hot formed.

3.  Dimensions (in mm)

3.1. Square hollow sections

Designation  Thickness Designation Thickness
25.4 x 25.4 x 2.65 2.65 50 x 50 x 2.90 2.90
x 3.25 x 3.25 x 3.65 x 3.65
x 4.05 x 4.05 x 4.50 x 4.50
32 x 32 x 2.65 2.65 63.5 x 63.5 x 3.25 3.25
x 3.25 x 3.25 x 3.65 x 3.65
x 4.05 x 4.05 x 4.50 x 4.50
38 x 38 x 2.90 2.90 75 x 75 x 3.25 3.25
x 3.25 x 3.25 x 4.05 x 4.05
x 4.05 x 4.05 x 4.85 x 4.85
45 x 45 x 2.9 2.9    
x 3.25 x 3.65    
x 4.50 x 4.5    

3.2. Rectangular hollow sections

Designation  Thickness Designation Thickness
40 x 25 x 2.65 2.65 76.2 x 50.8 x 3.25 3.25
x 3.25 x 3.25 x 3.65 x 3.65
x 4.05 x 4.05 x 4.50 x 4.50
50.8 x 25.4 x 2.90 2.90 90 x 38 x 2.65 2.65
x 3.25 x 3.25 x 3.25 x 3.25
x 4.05 x 4.05 x 4.05 x 4.05
63.5 x 38 x 2.90 2.90 100 x 50 x 3.25 3.25
x 3.65 x 3.65 x 4.05 x 4.05
x 4.50 x 4.50 x 4.85 x 4.85
76.2 x 38 x 3.25 3.3    
x 3.65 x 3.65    
x 4.50 x 4.50    
       
       
       

Note: For details regarding weight, moment of inertia, radius of gyration, elastic modulus and plastic modulus, see Tables 1 and 2 of the standard.

4. Weight – Shall be calculated on the basis that steel weighs 0.785 kg/cm2 per metre run.

5. Straightness – Shall not deviate by more than 1 in 600.

6. Oiling and painting – Shall be varnished, painted or oiled externally. 

7. Specific requirements hot formed sections

7.1. Tolerances

a)  Thickness: I)  Welded tubes ± 10 percent

                         ii)  Seamless tubes ± 12.5 percent

b)  Outside dimensions of sides  ± 1 percent of length of side

c)  Squareness of corners  90°  ± 1°

d)  Exact length ± 3 mm

Tensile properties

Grade  Tensile Strength, Min ( kgf/mm2 )   Yield Stress, Min  ( kgf/mm2 )
YSt 22 34 21.5
YSt 25 42 25
Yst  32  55 31.5

Elongation percent shall be not less than 950 divided by the tensile strength in kgf/mm2.

8. Specific requirements for cold formed sections

1.Tolerances

a)  Thickness ± 10 percent

b) Outside dimensions of sides:

    Largest outside dimension ± 0.5 mm

    across flats up to 63.5 mm

    Over 63.5 mm to 90 mm ± 0.60 mm

    Over 90 mm  ± 0.75 mm

 c)  Squareness of corners  90° ± 1°

 d)  Exact length ± 3 mm

2. Mechanical properties

8.2.1. Tensile properties of cold formed section

Grade  Tensile Strength, Min ( kgf/mm2 )   Yield Stress, Min  ( kgf/mm2 )
YSt 25 42 25
Yst  32  55

31.5

If sections supplied in cold formed conditions without any heat treatment are subjected to stress relieving, annealing, brazing welding or similar heating, the mechanical properties may be reduced at the heated parts as follows.

Grade  Tensile Strength, Min ( kgf/mm2 )   Yield Stress, Min  ( kgf/mm2 )
YSt 25 31.5 17.5
Yst 32  39.5

25

 8.2.2. Elongation percent shall not be less than 950 divided by the ultimate tensile strength in kgf/mm2.

Note: For test procedures, refer to IS : 1894 – 1962 Method for tensile testing of steel tubes ( first revision).

For detailed information, refer to IS: 4923 – 1968 Specification for hollow steel sections for structural use.

Annexure 7-A.19

SPECIFICATIONS FOR STEEL SHEET PILING SECTIONS  

  (Extract of IS: 2314-1963)

1. Scope – Lays down nominal dimensions and shape of hot rolled steel sheet piling sections.  Sectional properties of these sections as calculated on nominal dimensions are also included.  Some important requirements for sheet piles are (a) resistance to bending forces, (b) ease with which they can be driven and can be reclaimed for re-use, and (c) efficiency and water tightness. 

2. Designation – Designated with the letters ISPS followed by section modulus per metre of wall in cm3 and letters Z, U or F denoting Z-type, U-type or Flat type sections.

3. Material – Made from steel conforming to IS: 226-1975*, IS: 961-1975† or IS: 2062-1969‡

4. Dimensions

 

Designation

Weight per Metre

Weight per m2 of  Wall

Section Modulus per Metre of Wall

Moment of Inertia per Metre of Wall

Sectional Area per Metre

Perimeter per Meter Wall

Centre to Centre Distance of Joints

 

(kg/m)

(kg)

(cm3)

(cm4)

(cm2)

(cm)

(cm)

ISPS 1021Z

ISPS 1625U

ISPS 2222U

ISPS 100F

49.25

65.37

82.7

55.2

123.12

162.4

195.7

138

1 021

1 625

2 222

100

9 448.5

24 563

38 219

428

157

207

249

176

283

308

331

104

400.0

402.5

420.5

400.0

5. Tolerances

a) Weight -    + 4 percent

                      – 2.5

b) Length - Sections shall be supplied in lengths between 9 and 13.4 m, subject to a tolerance of +75  and  – 50mm.

For detailed information, refer to IS: 2314-1963 Specification for steel sheet piling sections.

Annexure 7–A.20

SPECIFICATIONS FOR STEEL WINDOWS FOR INDUSTRIAL BUILDINGS

(Extract of IS: 1361-1978)

1. Scope – Deals with steel windows suitable for use in industrial buildings and designed to suit openings based on a module of 10 cm.

2. Handing – Handing and direction of closing of sashes shall be according to IS: 4043-1969*.

3. Designation – By symbols denoting in sequence, IN (to indicate industrial window) x Width expressed in number of modules x Type = (F = fixed sash, C = centre – hung sash, B = bottom hung sash, T = top hung sash) x Height expressed in number of modules.

Examples:

a) IN 10 C 15 indicates industrial window for opening 10 module wide (100 cm) by 15 module high (150 cm) with centre hung ventilator

IN 10 C 10/IN 10 C 10

b) ------------------------------  indicates the combination of four windows, two of the type IN 10 C 15/IN 10 C 15 

IN 10 C 10 on top and two of the type IN 10 C 15 at the bottom, all the four of them coupled both horizontally and vertically.

4. Sizes and tolerances

Window Sizes :

IN10C10            IN22C10           IN16C15

IN10T10            IN22T10            IN16T15

IN10B10            IN22B10           IN16B15

IN16C10            IN10C15           IN22C15

IN16T10            IN10T15            IN22T15

IN16B10            IN10B15           IN22B15

IN10C20            IN22C20           IN16F10

IN10T20            IN22T20            IN16F15

IN10B20            IN22B20           IN16F20

IN16C10            IN10F10           IN22F10

IN16T10            IN10F15           IN22F15

IN16B10            IN10F20           IN22F20

c) Ventilator (opening part of a sash) shall be of one size and designed to fit into outer frame of IN10C10  and with 1.2 mm clearance.

d) Tolerance for overall dimensions - ±3 mm.

Note – Ventilator heights and widths to the outside of frames shall be derived after allowing 10 mm clearance all rounds for the purpose of fitting the sashes into modular openings.  Thus, width and depth of IN 16 C shall be 158 cm and 98 cm.

5. Material

5.1. Rolled steel sections shall conform to IS: 7452-1974. 

5.2. Pivots and Spring Catches – Non ferrous metal.

5.3. Glass – Shall conform to IS: 2835-1977 or IS: 5437-1969.

6. Holes for fixing, coupling and glazing – Holes for fixing and coupling sashes shall be provided in the web of the outside frame sections (and of outer ventilator frame sections where these occur at the perimeter of the sash).  Holes for glazing clips shall also be provided.

7. Fittings and fixing materials –

7.1. Centre-hung ventilators shall be mounted on a pair of brass cup pivots, each pivot consisting of an inner and an outer cup, permitting the swinging of the ventilator through at least 85º and so balanced that the ventilator shall be capable of remaining open in any desired position.

7.2. Centre-hung ventilators shall be provided with a pulley with centre at the bottom section of the ventilator, and attached with screws.

7.3. Centre-hung and bottom hung ventilators shall have a bronze spring catch in the centre of the top section, suitable for operation by hand or pole ( and by cord in case of centre-hung ventilators).  The former shall be provided with a 30 cm peg stay of steel or a 30 cm bronze cam opener to hold the ventilator open in three different positions.  Bottom-hung ventilators shall have folding side arms to limit the opening.

8. Composite Windows – Shall be dispatched unassembled, but complete with necessary coupling components. Each coupling member will increase the overall height or width by 25 mm maximum which includes manufacturing tolerances.

9. Glass – Sizes shall be as given below:

Pane Designation a b c d f
Width (mm) 269 304 292 304 304 292
Height (mm) 425 425 460 460 492 492

Note: For number of glass panes for each type of window see Fig.4 of the standard.

10. Finish – All sashes and coupling members shall be either galvanised or painted.

Annexure 7–A.21

 SPECIFICATIONS FOR ALUMINIUM DOORS, WINDOWS AND VENTILATORS

(Extract of IS:  1948-1961)

1. Scope – Requirements regarding material, fabrication and dimensions of aluminium doors, windows and ventilators, manufactured from extruded aluminium alloy sections of standard sizes and designs, complete with fittings, ready for being fixed into the buildings.  This standard does not cover the requirements for industrial doors, windows and ventilators.

2. Handing – Side-hung opening position of all doors and windows shall be said to be right hand or left hand according to the side on which they are hinged looking from the inside. 

3. Standard sizes, tolerances and designations –

a) Types and sizes:

6HF6 10HF6 12HF6 15HF6
6HT6 10HT6 12HT6 15HT6
6HC6 10HC6 12HC6 15HC6
       
6HF9 10HF9 12HF9 15HF9
6HS9 10HS9 12HS9 15HS9
6HT9      
       
6HF12 10HF12 12HF12 15HF12
6HS12 10HS12 12HS12 15HS12
       
6HF15 10HF15 12HF15 15HF15
6HS15 10HS15 12HS15 15HS15
       
6HF21 8HS21 12HS21 8HF6
8HC6      

b) Tolerances – For frames ± 1.5 mm.

Note 1 – the external dimensions fof width and height are derived after allowing 1.25 cm clearance all rounds for fitting into a modular opening based on 10 cm module. 

Note 2 – Designation is by symbols denoting width (number of modules in width of opening); type ( C = centre hung shutters; F = fixed glass panes; H = with horizontal glazing bars; N = without horizontal glazing bars; S = side-hung shutters; t = top-hung shutters); and height ( number of modules in height of opening).

Examples

a) A window of width 10 modules (97.5 cm) and height 9 modules (87.5 cm), having horizontal glazing bars and side-hung shutters is designated by 10 HS 9.

b) Two 10 module wide and 12 module high horizontally glazed side-hung windows coupled side by side with two fixed glass pane ventilators at top, each 10 module wide and 6 module high, is designated by

             10 HF 6/10 HF 6

 -----------------------------------------                     

         10 HS 12/10 HS 12

Note 3: Windows without horizontal glazing bars shall be designated by ‘N’ in place of ‘H’ in the range shown above.

Note 4: Doors and side lights shall only be coupled with 12 module (117.5 cm) high windows.

4. Materials

4.1. Alluminium Alloy – IS Designation HE 9 – WP and HV 9 – WP.

4.2. Glass Panes – Shall weight at least 7.5 kg/m2.  Glazing shall be outside of frames.

Note – For sizes of glass panes see Table 1 of the Standard.

5. Fabrication

5.1. Side – Hung shutters – Hinges projecting type 67 mm wide.  Friction hinges or peg stays (300 mm long) shall be provided.

5.2. Centre Hung Ventilators – Shall be hung on two pairs of cup pivots of aluminium alloy (IS Designation NS – 4).

5.3. Doors – Outer fixed frame shall be of section A1– F x 8. Shutter frame shall be of either hollow section A1– HF x 5 and A – HF x 6 or of solid sections A1 – F x 5 and A1– F x 6.

5.3.1. Hinges – Shall be of 50 mm projecting type.

5.3.2. A suitable lock for the door operable either from inside or outside shall be provided.

5.3.3. In double shutter doors the first closing shutter shall have a concealed aluminium alloy bolt at top and bottom. 

5.4. Composite units – Doors shall be coupled t windows or side lights by extruded aluminium sections made from aluminium conforming to IS Designation HE 9 – WP.

5.5. Weather bar – Where a coupling member is fitted over an external opening shutter, the coupling member should incorporate an integrally extruded weather bar. 

6. Position of bolts, fixing screws and lugs – Outer frames shall be provided with fixing holes centrally in the web of the sections.

Note: For details regarding positions of fixing holes and member of fixing lugs see 7 of the standard.

7. Finish

7.1. Matt, scratch – brush or polished.  May be anodized additionally.

7.2. A thick layer of clear transparent lacquer based on methacrylates or cellulose butyrate shall be applied by suppliers to protect the surface from wet cement during construction.  This lacquer coating shall be removed after installation is completed.

Annexure 7–A.22  

SPECIFICATIONS FOR ALUMINIUM WINDOWS FOR INDUSTRIAL BUILDINGS

(Extract of IS: 1949-1961)

1. Scope – Deals with aluminium windows suitable for use in industrial buildings and designed to suit openings based on a module of 10 cm.

2. Designation – By symbols IN (to indicate industrial window) x Width expressed in number of modules x Type (F = fixed sash; C = centre hung sash; B = bottom-hung sash; T = top-hung sash) x Height expressed in number of modules.

Examples:

a. IN 10 C 15 indicate window for opening 10 module wide (100 cm) by 15 module high ( 150 cm) with centre-hung ventilator.

b. Composite windows      

  IN 10 C 10/IN 10 C 10

---------------------------------- 

  IN 10 C 15/IN 10 C 15 

Indicates the combination of four windows, two of the type IN 10 C 10 on top and two of the type IN 10 C 15 at bottom, all the four of them coupled both horizontally and vertically.

3. Sizes and tolerances

a) Sizes

IN10C10 IN22C10 IN16C15 IN10C20 IN22C20 IN16F10
IN10T10 IN22T10 IN16T15 IN10T20 IN22T20 IN16F15
IN10B10 IN22B10 IN16B15 IN10B20 IN22B20 IN16F20
           
IN16C10 IN10C15 IN22C15 IN16C20 IN10F10 IN22F10
IN16T10 IN10T15 IN22T15 IN16T20 IN10F15 IN22F15
IN16B10 IN10B15 IN22B15 IN16B20 IN10F20 IN22F20

b) Ventilators (opening part of a sash) shall be of one size and designed to fit into outer frame of IN 10 C 10 and with 1.2-mm clearance.

c) Tolerance for overall dimensions ± 3 mm.

Note – The overall width and height of window is smaller than dimensions of modular opening by 2.5 cm, allowing a clearance of 1.25 cm all round.  Thus, width and height of INC10C5 = 97.5 x 147.5 cm.

4. Material

  1. Aluminium extruded section: IS Designation HE9 – WP.  Hollow sections shall conform to IS Designation HV9 – WP.
  2. Cord-eyes, pulleys, brackets and catch plates shall be of aluminium or galvanized or cadmium plated steel.
  3. Pivots, peg stays and spring catches shall be of non-ferrous metal.
  4. Glass panes - Shall weigh 7.5 kg/m2.  Sizes of glass panes shall be as given below:
Pane Designation a b c d f
Width (mm) 265 300 290 300 300 290
Height (mm) 420 420 455 455 490 490

Note: For number of glass panes for each type of window sees Fig.5 of the standard.

5. Holes for fixing, coupling and glazing – Holes for fixing and coupling sashes shall be provided in the web of the outside frame sections and of outer ventilator frame sections where these occur at the perimeter of the sash.  Holes for glazing chips shall also be provided, one hole being located in web of the section or tee, on each side of each pane. 

6. Fitting and fixing materials

6.1. Centre-hung ventilators shall be mounted on a pair of cup-pivots made out of aluminium alloy sheet or chromium plated brass and each pivot consisting of a inner and outer cup, permitting the swinging of the ventilator through at least 85°.  The ventilator shall be so balanced that it can remain open in any desired position. 

6.2. Centre–hung and bottom-hung ventilators shall have cast aluminium or bronze spring catch in the centre of the top section, suitable for operation by hand or pole (chord in case of centre-hung).

6.3. Bottom-hung and top-hung ventilators shall be hung on aluminium alloy hinges.  The former shall be provided with a pair of aluminium alloy folding side arms (to limit the opening) and the latter with a 300 mm long peg stay.  Alternatively, top-hung ventilator may be provided with 30-cm cam opener.

6.4. Two spring glazing clips per pane shall be provided

7. Composite windows – Shall be dispatched unassembled, but complete with necessary components.  Each coupling member will increase the overall height or width by 25 mm.

8. Finish - Matt, scratch-brush or polished may be anodized additionally.  A thick layer of transparent lacquer, based on methacrylates or cellulose butyrate, shall be applied, by the suppliers, to protect the surface from action of wet cement during installation.  This lacquer coating shall be removed after installation is completed. 

Annexure 7– A.23

SPECIFICATIONS FOR STEEL DOOR FRAMES    (Extract of IS:  4351-1976)

1. Scope – Requirements regarding material, dimensions and construction of steel doorframes for internal and external use.  Aluminium doorframes not covered.

2. Material – Shall be manufactured from commercial mild steel sheets of 1.25 mm thickness, conforming to IS: 513 – 1973 or IS: 1079 - 1973.

3. Sizes, tolerances and designation

Designation Overall Width (mm) Overall Height (mm)
8PX20 79 199
9PX20 89 199
10PX20 99 199
12PX20 119 199
8PX21 79 209
9PX21 89 209
10PX21 99 209
12PX21 119 209

b) Tolerance     ± 2 mm.

Note 1: ‘X’ in the designation stands for profile designation, such as A, B or C.

Profile A = 105 x 60 mm rebated for one set of shutter.

Profile B = 125 x 60 mm rebated for one set of shutter.

Profile C = 165 x 60 mm rebated for two sets of shutters.

Note 2: Sizes are derived after allowing 5 mm clearance all round for fitting the frame into a modular opening based on 10 cm module.

Note 3: Designation by symbols denoting width (number of modules in width of opening); type (P = pressed steel frame); profile (A ,B or C ) and height ( number of modules in height of opening).

4.Base ties and angle thresholds – Base ties of pressed mild steel 1.25 mm thick adjustable to suit floor thickness of 25, 30, 35 or 40 mm and removable, or alternatively, thresholds of mild steel angle 50 x 25 mm, Min, shall be provided for external door frames.

5. Fittings

5.1. Fixing lugs – There shall be three adjustable lugs with split and tail to each jamb without fanlight, and four for jamb with fanlight.  Head 25 mm wide x 1.6 mm thick, Min, and 95, 120 or 160 mm long

for profiles A, B and C respectively.  Tail shall be 200 mm long, 40 mm. Min wide and 1 mm, Min thick.

5.2. Hinges

a) Frames for doors 89 cm wide and above – 3 hinges welded to one jamb.

b) Frames for doors 99 cm wide and above – 6 hinges, 3 welded to each jamb.

5.3. Lock strike plate of steel, complete with mortar guard, shall be provided.

5.4. Shock Absorbers – Minimum 3 buffers, for side-hung door, and 2 buffers for double shutter door.

6. Finish – Doorframes shall be hot-dip galvanized or painted.

Annexure 7–A.24

 SPECIFICATIONS FOR METAL ROLLING SHUTTERS AND ROLLING GRILLS

(Extract of IS: 6248-1979)

1. Scope – Requirements regarding materials, fabrication and finish of metal rolling shutters and rolling grills for normal use. 

2. Sizes - Specified by clear width (W) and clear height (H) of the opening.  Width shall always be mentioned first.  Stopper height shall be 10 cm less than clear height, unless otherwise specified. 

Note: Since the term ‘rolling shutters’ is more commonly used; the reference in this standard is mainly to rolling shutters.  However, since rolling shutters and rolling grills are similar in design, construction and operation, all references to rolling shutters in this standard shall apply to rolling grills also.  Special features of rolling grills, as different from rolling shutters have also been given. 

3. Types and applicable sizes

a) Self-Coiling Type (Push-Pull Type or Manual type) – For sizes up to a clear areas of 8 m2 without ball bearings and 12 m2 with ball bearings. 

b) Gear-Operated Type (Mechanical Type) – Shall be fitted with ball bearings.  Used for a clear area up to 25 m2 if operated by bevel gearbox and crank handle, and up to 35 m2 if operated by chain wheel and hand chain, mounted directly on the worm shaft. 

c) Electrically-Operated Type – For use up to about 50-m2 clear area.  Operated by electric motor on 400/440 V, 3 phase, 50 cycles ac supply.  Speed of movements of curtain shall not exceed about 10 cm/s.

4. Requirements

4.1. Curtain shall be built up of interlocking lath section formed from cold rolled steel strips.  Thickness of sheets not less than 0.9 mm for shutters up to 3.5 m width and 1.20 mm for 3.5 m width and above.

4.2. Lock plate – Made of mild steel sheet not less than 3.15 mm thick, reinforced with mild steel angle section not less than 35 x 35 x 5 mm.  Alternatively, it may be fabricated out of mild steel angles or ‘Tee’ sections not less than 5 mm thick. 

4.3. Guide channels and bracket plates – Fabricated out of mild steel sheets of minimum 3.15 mm thickness.

4.4. Hood covers – For width up to 2.5 m, a properly fabricated and reinforced bottom lock plate shall be provided to give protection.  For widths above 2.5 m, anchorage rods or central hasp and staple, or both may be provided. 

5.Rolling grills – Curtains may be built of aluminium alloy or cold rolled steel sheet links of 0.9 mm thickness assembled on tubes or rods, or out of 8 mm dia mild steel or aluminium alloy round bars.

5.1.Rolling shutter–cum-grill – In situations where a certain amount of ventilation combined with safety is called for the rolling shutter may have a small rolling grill portion either at top or at bottom or at both places.  Height of grill portion shall be 0.5 m maximum.

6. Painting – All component parts (except springs and the inside of guide channels) shall be given one coat of a brushing quality ready mixed primer before dispatch.  Portions where there is contact between aluminium and steel shall be painted with zinc chromate primer.

Note: For details regarding types based on position of fixing, fabrication, optional features, operation, etc, refer to the standard.

Annexure 7-A.25

SPECIFICATIONS FOR GALVANISED STEEL SHEETS (PLAIN AND CORRUGATED)

 (Extract of IS: 277-1977)

1. Scope – Requirements for the following 4 classes of plain and corrugated galvanized steel sheets produced by hot dip process.

Class 1 Extra heavy coating of zinc, nominal 750 g/m2

Class 2 Heavy coating of zinc, nominal 600 g/m2

Class 3 Medium coating of zinc, nominal 450 g/m2 and

Class 4 Light coating of zinc, nominal 375 g/m2

This standard also covers the requirements for galvanized steel sheets in coil form.

2. Freedom from defects – Galvanized plain sheets shall be reasonably flat and free from twist.  Galvanized corrugated sheets shall be free from twist or buckle and shall have uniform corrugations, true in depth and pitch and parallel to the sides of the sheet.

3.  Dimensions

Length – 1.8, 2.2, 2.5, 2.8 and 3 m.

Width – 0.75 or 0.90 m

Thickness – 1.60, 1.25, 1.00, 0.80 and 0.63 mm

Corrugation, Depth – 18 mm (nominal); pitch 75 mm (nominal);

Number of corrugations per sheet    8    10     11

Width before corrugation, mm    750    900    1000  

Overall width, after corrugation between  660    800   885

Crowns of outside corrugations, mm.

Note: For details regarding dimensions and weights, see 6 of the standard.

4. Tolerances

Length - + 10 mm or + 0.5 percent of length whichever is higher.

Overall width after corrugation - ± 10 mm

Length of diagonals of sheet shall not differ by more than 20 mm.

Depth of corrugation - ± 1.5 mm

Pitch of corrugation - ±  2.0 mm

Mass of an individual sheet - ± 10 percent

On each bundle of sheets -   ± 5 percent

5.  Bend test – Test piece shall withstand bending through 180o round a mandrel of specified diameter without peeling or flaking of zinc coating.

6.  Zinc coating – The weight of coating, when tested according to prescribed methods, shall be within the following limits.

Class  1 2 3 4
Specified coating (nominal), g/m2      750 600 450 375
Minimum coating by diagonal triple spot test, g/m2  625 500 350 275
Minimum coating by single spot test g/m2  550 425 300 250

Note: For test procedures see 8 and 10 of the standard.

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