STEEL & ALUMINIUM WORKS -1



STEEL, IRON AND ALUMINIUM WORKS

7.1 Materials

7.1.1. Steel - All finished steel shall be well and cleanly rolled to the dimensions and weight specified by Bureau of Indian Standards subject to permissible tolerances as per IS: 1852. A List of BI Standards applicable to this section is Annexure 7-A.1. The finished materials shall be reasonably free from cracks, surface flaws laminations, rough and imperfect edges and all other harmful defects.

7.1.2. Steel sections, shall be free from excessive rust, scaling and pitting and shall be well protected.  The decision of the engineer regarding rejecting any steel section on account of any of the above defects shall be final and binding.

7.1.3. Structural steel work shall conform to the following requirements. The following varieties of steel should be used for structural purposes

7.1.4. S.T. 42S - The standard quality steel designated as ST–42S, conforming to IS: 226 shall be used for all types of structure (riveted or bolted) including those subject to dynamic loading and where fatigue, wide fluctuation of stresses  are involved, as for example crane gantry girders, road and rail bridges etc. It is also suitable for welded structures provided that the thickness of materials does not exceed 20 mm.

7.1.5. S.T. 42W - The fusion welding quality steel designated as S.T. 42W, conforming to IS: 2062 shall be used for structures subject to dynamic loading (Wind load is not to be considered as dynamic load for this purpose) where welding is employed for fabrication and where fatigue, wide fluctuation of, stresses reversal of stress and great restraint are involved as for example, crane gantry girders and road and rail bridges.

7.1.6. S.T. 420 - The ordinary quality steel designated as S. T. 420 conforming IS: 1977 shall be used for structures not subjected to dynamic loading other than wind loads where welding is not employed or / and structures not situated in earth quake zones or / and design has not been based on plastic theory.

7.1.7. S.T. 320 - The ordinary quality steel designated as S. T. 420 conforming to IS: 1977 shall be used for doors, window frames, window bars, grills, steel gates, hand railing, builders hardware, fencing post, tie bars etc.

7.1.8. Casting shall be cast from cast iron of grade FG 150 conforming to IS: 210-1978, Specification for grey iron castings.  The castings shall be sound, clean and free from porosity, blow holes, hard spots, cold shuts (i.e. irregularities due to casting at too low a temperature), distortion and other harmful defects.  They shall be well dressed and fettled, accurately moulded in accordance with the pattern/drawing and shall be of uniform thickness except where the design necessitates variation.  Abrupt changes in the section of adjoining members shall be avoided as far as possible.  Unless otherwise indicated edges of castings shall be rounded and internal angles finished with an angle fillet.  No welding or repairs shall be carried out, unless otherwise indicated. 

7.1.9. Rivets - Rivets shall be made from rivet bars of mild steel as per IS: 1148-1982.  High tensile rivet bars shall conform to IS: 1149-1982.

7.1.10. Bolts - These are of two type’s namely turned and fitted bolts and black bolts.  Turned & fitted bolts are turned to exact diameter in automatic lathe.  For these bolts, whether reamed or drilled bolts, the same unit stresses are allowed as for rivets.  In case of black bolts which are not finished to exact sizes, a lower working stress other than for turned bolts is adopted.  They shall conform to IS: 1367 Technical supply conditions for threaded steel fasteners.

7.1.11. Electrodes - The electrodes required for metal arc welding shall be covered electrodes and shall conform to IS:  814-1991.

7.2. Workmanship – General

7.2.1. Structural steel work riveted, bolted or welded shall be carried out described in IS: 800-1984, Code of practice for use of structural steel in general building construction.

7.2.2. Straightening and bending - All material shall be straight and if necessary, before being worked shall be straightened and flattened by pressure, unless required to be of curvilinear form and shall be free from twists.  Straightening of steel by hammer blows is not permitted. All bending and cutting shall be carried out in cold condition, unless otherwise directed, in such manner as not to impair the strength of the metal.

7.2.3. Cutting and machining - Member shall be cut mechanically by saw or shear or by oxyacetylene flame.  All sharp rough or broken edges and all edges of joints which are subjected to tensile or oscillating stresses shall be grounded.  No electric metal arc cutting shall be allowed.  All edges cut by oxyacetylene pores shall be cleaned of impurities and slag prior to assembly, cutting tolerance shall be as follows (a) For member connected at ends ± 1 mm. (b) Elsewhere ± 3 mm.

When compression members depend on contact surfaces for stress transmission, then ends of columns and bases together with gussets, angles and channels (after riveting / welding together) shall be accurately measured so that the parts connected butt over the entire surfaces of contact.  Columns at bases or at caps or at butt joints need to be machined.

7.2.4. Holes - All holes shall be accurately marked and drilled.  Holes through more than one thickness shall preferably be drilled together after the members are assembled and tightly clamped or bolted together.  In such cases, if required, these parts shall be separated after drilling and burrs removed.  For thickness of materials less than 16 mm the holes may be punched 3 mm less in diameter than the required size and may be reamed to the full diameter after assembly.  Finished holes for rivets and black bolts shall be more than 1.5 mm (2.0 mm for rivets and bolts of diameter more than 25 mm) in diameter larger than the diameter of rivets and bolts passing through them. All matching holes for rivets shall be so prepared that a gauge 0.8 mm diameter less than the hole can pass freely through the members assembled for riveting.  Holes other than those required for close tolerance may be punched full size through material not less than 12 mm thick.

All holes shall have their axis perpendicular to the surface bored through Holes through two or more members shall be truly concentric.  No rivet or bolt hole shall be nearer the edge of the member than a distance equal to its own diameter.  Holes shall not be formed by gas cutting process.

7.2.5. Assembly

7.2.5.1. Laying out - Steel structure shall be laid out on a level platform to full scale and to full size or in parts as shown on working drawings or as directed by engineer. Wooden templates 12 mm to 19 mm thick or metal sheet templates shall be made to correspond to each member and part; rivet holes shall be marked accurately on them and drilled.  The templates shall be laid on the steel members and holes for riveting and bolting marked on them.  The ends of the steel members shall also be marked for cutting.  The base of steel columns and the positions of anchor bolts shall be carefully set out. The component parts shall  be assembled in such a manner that they are neither twisted nor otherwise damaged and shall be so prepared that the specified cambers, if any, are provided.  All box sections shall be sealed so as to prevent the access of moisture to the inside of the members.

Assembly shall be done by using assembly fixtures, jigs and stands which facilitate high quality assembly with proper safety.  Misalignment and distortion of parts after assembly shall not be allowed; only thoroughly straightened parts free from burrs, grease, rust, etc. shall be allowed for assembly.

Temporary connection of parts during assembly shall be done in the following way:

  1. For welded structures joining shall be done by means of tack weld, fastening devices and fixtures.
  2. For riveted and bolted structures joining shall be done by adequate number of bolts. If tack welding is permitted, in such cases the same shall be removed after the work is over.
  3. For riveted structures in which holes are to be drilled after assembly, joining shall be done by appropriate fixtures.

Tack welding shall be done on the side and along the line of the weld.  Tack weld dimension all be minimum, welding being carried out with similar electrodes as the final welding and the tacks shall completely fuse with the final weld metal. In case splicing is necessary, the individual members shall be spliced first before assembly and before final welding with other members.

For riveted structures, members shall be well tightened by assembly bolts in every third hole maximum distance between bolts shall not exceed 500 mm.  To prevent stiffening drift pins shall be used 30 per cent of the assembly bolts.  After tightening, the gap between members to be jointed shall be checked by 0.2 mm thick feeler gauge which should not go inside by more than 2 mm, looseness of bolts shall be checked by tapping with a test hammer.

7.2.6. Riveting

Riveting shall be done by pneumatic riveting or hydraulic riveting equipment, riveting of diameter less than 10 mm may be fitted cold.  In cold riveting the rivets are driven with the aid of powerful pneumatic or electrical clamps and the holes filled with sufficient tightness.  However where such facilities are not available, hand riveting may be permitted by the engineer.

Members to be riveted shall be properly pinned, or bolted and rigidly held together while riveting. Rivets shall be heated uniformly throughout the length without burning or excess scaling and shall be of sufficient length to provide ahead of standard dimension. They shall, when driven, completely fill the holes and if countersunk, the countersinking shall be fully filled by the rivet.  Any proudness of countersunk head shall be dressed off flush.  All loose, burnt and badly formed or otherwise defective rivets shall be cut out and replaced before the structure is loaded.  The heads of rivets shall be central to shanks and shall grip the assembled members firmly.  In cutting out rivets care shall be taken so as not to injure the assembled members.  Caulking or recupping shall not be permitted.

7.2.7. Bolting

Bolt heads and nuts shall be of such length as to project one clear thread beyond the nuts when fixed in position, and these shall fit in the holes without any shake.  The nuts shall fit in the threaded ends of bolts properly.

Round washers shall be placed under the heads and nuts of permanent bolts. Maximum two washers for one nut and one for each bolt head shall be used.  Both threads shall be outside the limits of joining members and unthreaded portion of bolt shall not be outside the washer.

Where there is risk of the nuts being removed or becoming loose due to vibration or reversal of stresses, these shall be secured from slackening by the use of lock-nuts or spring washers, as directed by the engineer. Bolts, nuts and washers shall be thoroughly cleaned and dipped in double boiled linseed oil before use. Quality of lightening of bolts shall be inspected by tapping them with a hammer. The bolt shall not be shaken or shifted. The bolts shall be tightened starting from centre of the joint towards the edge.

7.2.8. Welding

Welding shall be done by metal arc process unless otherwise permitted by the engineer, in writing, in accordance with IS: 816-1969 Code of Practice for use of metal arc welding of general construction in mild steel, and IS: 9595-1980.  Recommendation of Metal Arc Welding, regarding workmanship welding method, welding procedure with suitable electrodes and wire flux, combinations, quality of welds, correction of weld faults etc.

7.2.9. Preparation of members for welding

Assembly of structural members shall be made with proper jigs and fixtures to ensure correct positioning of members (angles, axis, nodes etc.).

Sharp edges, rust of cut edges, notches, irregularities and fissures due to faulty cutting shall be chipped or ground or filed over the length of the affected area, deep enough to remove faults completely. Edge preparation for welding shall be carefully and accurately made so as to facilitate a good joint. Generally no special edge preparation shall be required for members under 8 mm thick.

Edge preparation (beveling) denotes cutting of the same so as to result in V, X, K or U seam shapes as per IS: 9595-1980.

The members to be assembled shall be clean and dry on the welding edges. Under no circumstances shall wet, greasy rust of dirt covered parts be assembled. Joints shall be kept free from any foreign matter, likely to get into the gaps between members to be welded.

Before assembly, the edges to be welded as well as adjacent areas extending for at least 20 mm shall be cleaned (Until metallic polish is achieved). When assembling members proper care shall be taken of welding shrinkage and distortions, as the drawing dimensions cover finished dimensions of the structure. The elements shall be got checked and approved by the engineer before assembly wherever it is specified. The permissible tolerances for assembly of members preparatory to welding shall be as per IS: 9595. After assembly has been checked, temporary tack welding in position shall be done by electric welding; keeping in view finished dimensions of the structure. Preheating of members to be joined to be carried put as per standards wherever necessary.

7.2.10. Butt welds (Fig. 1)

The form of joint, angle between fusion faces, gap between parts and the welding procedure shall be such that the welded joint shall comply with the design requirements. The ends of butt joints in plate shall be welded so as to provide full throat thickness. In the gas welded condition, the weld face shall be proud of the surface of the parent metal. Where a flush surface is required, the excess metal shall be dressed off. Where no dressing is to be carried out, the permissible weld profile shall be as specified in the relevant IS.

For butt  weld, where these are to be welded for both sides, certain welding procedures allow this to be done without back going, but where complete penetration cannot be achieved, the back of the first run shall be gouged out to clean sound metal before welding is started on the gouged outside.

7.2.11. Fillet Welds (Fig. 1)

A fillet weld as deposited shall be not less than the specified dimensions indicated as throat thickness and/or leg thickness taking into account penetration processor partial penetration. For concave fillet welds the actual throat thickness shall be not less than 0.7 times the specified leg length.  For convex fillet welds, the actual throat thickness shall be not less than 0.9 times the specified leg length.

7.2.12. Preparation of joint faces

If preparation or cutting of material is necessary, this shall be done by shearing, chipping, grinding, machining, thermal cutting or thermal gouging.  When shearing is used the effect of work hardening shall be taken care of to ensure that there is no cracking of the edges.  Removal of 1 mm to 2 mm from a cut face normally eliminates the layer of hardness.

7.2.13. Fusion faces

Fusion faces and adjacent surfaces shall be free from cracks, notches or other irregularities which might be the cause of defects or would interfere with the deposition of the weld.  They shall also be free from heavy scale, moisture, oil, paint and any other substance which might affect the quality of weld or impede the progress of welding.

7.2.14. Assembly for welding

Jigs and manipulators should be used, where practicable, so that the welding can be carried out in the most suitable position.  Jigs shall maintain the alignment with the minimum restraint so as to reduce the possibility of lock in stresses.

7.2.15. Alignment of butt joint

The root edges or root faces of butt joints shall not be out of alignment by more than 25 per cent of the thickness of the thinner material for material up to 12 mm thick or by more than 3 mm for thicker material.  For certain applications closer tolerances may be necessary for proper alignment.

7.2.16. Fit up of parts jointed by fillet welds

The edges and surfaces to be jointed by fillet welds shall be in as close contact as possible since any gap increases the risk of cracking but in no case should the gap exceed 3 mm.

7.2.17. Tack welds (Fig.1)

Tack welds shall be not less than the throat thickness or leg lengths of the root run to be used in the joint.  The length of the tack weld shall not be less than four times the thickness of the thicker part or 50 mm whichever is similar.  If smaller tack welds are desired, these shall be so indicated.

Where the tack weld is incorporated in a welded joint, the shape of the tack shall be suitable for incorporation in the finished weld and it shall be free from cracks and other deposition faults.

7.2.18. Protection from weather

Surface to be welded shall be dry.  When rain or snow is falling or during periods of high wind, necessary precautions shall be taken for outdoor welding arc. Warming shall be carried out at all ambient temperatures below 10 degree C.

7.2.19. Inter–run cleaning

Each run of weld bead and each layer of weld shall be thoroughly cleaned of slag, spatters, etc. before depositing subsequent bead or weld with particular reference to thorough cleaning of toes of the welds.  Visible defects such as cracks, cavities and other deposition faults, if any, shall be removed to sound metal before depositing subsequent run or layer of weld.

7.2.20. Welding procedure

Welding shall be carried out only by fully trained and experienced welders as tested and approved by the engineer.  Qualification tests for welders as well as tests for approval of electrodes will be carried out as per IS: 823-1964. The nature of test for performance qualification for welders shall commensurate with the quality of welding required on this work as judged by the engineer. The steel structures shall be automatically, semi automatically or manually welded. Welding shall be only after the checks have been carried out. Welding procedures and Tests for welders shall be conducted as per IS: 9595 and approved by the engineer. The welder shall mark with his identification mark on each element welded by him. When welding is carried out in open air steps shall be taken to protect the places of welding against wind or rain.  The electrodes wire and parts being weld on shall be dry. Before beginning the welding operation each joint shall be checked to assure that the parts to be welded are clean and root gaps provided as per IS: 9595. For continuing the welding of seams discontinued due to some reasons the end of the discontinued seam shall be melted in order to obtain a good continuity.  Before resuming the welding operation the groove as well as the adjacent parts shall be well cleaned for a length of approximately 50 mm. For single butt welds (in V, ½ V or U) and double butt welds (in K, double U, etc.) the re-welding of the root butt is mandatory but only after the metal deposition on the root has been cleaned by back gouging or chipping. The welding seams shall be left to cool slowly.  The contractor shall not be allowed to cool the welds quickly by any method. For multilayer welding before welding the following layer, the formerly welded layer shall be cleaned metal bright by light chipping and wire brushing.  Backing strips shall not be allowed. The order and method of welding shall be so that (a) no unacceptable deformation appears in the welded parts. (b) due margin  is provided to compensate for contraction due to welding in order to avoid any high permanent stresses. The defects in welds must be rectified according to IS: 9595-1980 and as per instruction of engineer.

7.2.21. Approval and testing of welders

The contractor shall satisfy the engineer that the welder is suitable for the work upon which they will be employed.

7.2.22. Weld inspection

The weld seems shall satisfy the following

  1. Shall correspond to design shapes and dimensions.(b)Shall not have any defects such as cracks, incomplete penetration and fusion under cuts, rough surfaces, burns, blow holes and porosity etc. beyond permissible. During the welding operation and approval of finished elements inspections and tests shall be made as shown in Table 1 below

Table 1 Extent of inspection and testing

Sl.No

Inspection of test

Coverage

Procedure

Evaluation and remedy of defects

1

Inspection of weld seam Appearance

All welds

Naked eye or lens

All faulty welds shall be rectified.

2

Checking of sizes

Atleast one for each weld  seam

Ordinary measuring instruments

(Rule template)

Should faulty weld be found, all welds shall be checked and all defects shall be rectified.

 

Mechanical test for welding procedure, performance & electrodes.

 

As per IS: 9595

As per IS: 9595

The mechanical characteristics of the welded joints shall be as in IS:  9595.

7.2.23. Quality of welds and corrections

Welded joints shall be from defects that would impair the service performance of the construction.  All welds shall be free from incomplete penetration, incomplete fusion, slag inclusion, burns, un-welded crators, undercuts and cracks in the weld metal or in the heat affected zone, porosity etc.  Unacceptable undercutting shall be made good by grinding.  In case of shrinkage cracks, cracks in parent plate and crator, defective portions shall be removed down to sound metal and re-welded. Whenever corrections necessitate the deposition of additional weld metal, electrode of a size not exceeding 4 mm may be used.  Rectification of welds by caulking shall not be permitted.

7.2.24. Cleaning - All welds shall be cleaned of slag and other deposits after completion; till the work is inspected and approved, painting shall not be done.

7.2.25. Plaining of ends

Plaining of ends of members like Column ends shall be done by grinding where so specified.

Plaining of but welded member shall be done after these have been assembled and the edges be removed with grinding machine or file.

The following tolerances shall be permitted on members that have been plained

  1. The length of member having both ends plained max ± 2 mm with respect to design.
  2. Level difference between plained surface = 0.3 mm.
  3. Deviation between plained surface and member axis = max 1 /5000.

7.2.26. Safety and health

The contractor shall ensure that the safety requirements and health provisions laid down in IS:  818-1968 Code of Practice for safety and health requirements in electric and gas welding and cutting operations are complied with during welding operations.  The contractors shall also provide equipment for eye and face protection during welding as laid down in IS:  1179-1967.  Fire precautions shall be taken in accordance with IS:  3016-1982 Code of Practice for fire precautions in welding and cutting operations.

7.2.27. Erection

Erection works shall be performed in accordance with the general construction schedule. A scheme shall be worked before the commencement of the erection which shall also contain rules for safety precautions as detailed in IS:  7205-1973. (Safety Code for erection of structural steel work).

Anchor bolts for fastening of steel structures shall be set in designed position and grouted along with foundations. Alternatively anchor bolts should be provided in the concrete foundations with bolt boxes and anchor channels for the purpose of flexibility and grouted after final alignment and leveling of column. The gaps between the bearing surface of foundation and bottom of the structures to be erected shall be filled properly by cement grouting.  Grouting shall be done after the verification and proper positioning of the structures but before encasing the structures with concrete if specified. Damaged structural members shall be examined and rectified or replaced as directed. The erected parts of the structure shall be stable during all the stages of errection; and structural elements to be erected shall be stable and strong to bear erection loads. Working on the already erected structures is permitted only after they are finally fixed. Erection of structures of each tier high structures shall be executed only after the relevant fastening of lower tier by the permanent or temporary fastening devices as per schedule of execution of work and certified for safety. The joint and mating surface including the mating planes, strips and filler or spacers shall be cleaned of dust, rust and water.

Erected structural members shall be firmly fastened by bolts and drifts, permanent or provisional tacking, crossing bars and so on before the erection crane book is removed. The trusses shall be lifted only at nodes. The trusses above 12 m span shall not be slinged at the apex, as it will develop compression stresses in the bottom tie member. It shall be lifted by slinging at two mid points of rafters, which shall be temporarily braced by a wooden member of suitable section.  After the trusses are placed in position, purlins and wind bracings shall be fixed as soon as possible.  The end of truss which faces the prevailing winds shall be fixed with holding down bolts and the other end kept free to move.  In case of small truss of span say up to 12 m the free end of the truss shall be laid on steel plate as per design and the holes for holding down bolts shall be made in the form of oblong slot so as to permit the free movement of the truss end.  For large spans, the free end of the truss shall be provided with suitable rocker and roller bearing where indicated.

7.2.28. Erection joints

While erecting, holes to be riveted shall be fitted with temporary bolts and drifts of diameters equal to those of the holes.  It is necessary to initial drifts for accurate matching of holes. Number of bolts and drifts shall not be less than 40 per cent of total number of holes. Forces applied to drifts shall be same as approved for rivets. Number of drifts shall be 10 per cent of number of holes.

The number, size and length of tack welds in erection joints bearing erection forces shall be as indicated. For the erection joints which do not bear the erection forces the length of tack welds shall be minimum 10 per cent of the designed weld length of the joints.

Welding, riveting and final fastening or permanent bolts shall be done only after the inspection of the structural elements for their positions. Head bolts and nuts shall perfectly be in touch with the surfaces of structures and washers.

7.2.29. Tolerance allowed in erection

Building without crane - The maximum Tolerance for line and level of steel structure shall be +/ 3.00 mm on any part of the structure. The structure shall not be out of plumb more than 5.00 mm each 10 metre section in height and not more than 7.00 mm per 30 metre section.  These tolerances shall apply to all parts of structure unless otherwise specified.

Tolerance allowed in erection of steel structure containing cranes shall be as per following Table.

Table

Component

Description

Tolerance allowed

Main columns

And roof posts

a

 

i

Shifting of columns axis at foundation level with respect to building line:

In longitudinal direction

 

 

± 5.00 mm

 

ii

In lateral direction

± 5.00 mm

 

b

Deviation of both major column axis from vertical between foundation and other member connection levels:

 

 

i

For a column upto and including 10 m height

± 5.00 mm from true vertical.

 

ii

For a column greater than 10 m but less than 40 m height

± 5.00 mm from True vertical for any 10 M length measured between connection levels but not more than ± 8.00 mm for 30 m length.

 

c

For adjacent pairs of columns across the width of the building prior to placing of truss.

± 5.00 on true span

 

d

For any individual column deviation of any bearing or resting level from levels shown on drawings.

± 5.00 mm

 

e

For adjacent pairs of columns either across the width of buildings or longitudinally level difference allowed between bearing or seating level supposed to be at the same level.

5.00 mm

Trusses

a

Deviation at centre of span or upper chord member from vertical plane running through centre of bottom chord.

1/500 of the span or 10 mm whichever is less.

 

b

Lateral displacement of top chord at centre of span from vertical plane running through centre of supports.

1/250 of depth of truss or 20 mm whichever is less.

7.3. Steel reinforcement

Steel reinforcement for concrete - Steel reinforcement shall be mild steel bars, deformed bars, steel wire fabrics and of grade / types as indicated.

Mild Steel Bars shall be of grade I or grade II indicated and conforming to IS: 432 (Part I)-1982 and (part II) (Annexure 7-A.7 & 7-A.8) Specification for mild steel and medium tensile steel bars.  Alternatively mild steel shall be of grade Fe 410S conforming to IS: 226-1975 of or grade Fe 4100 conforming to IS: 1977-(1975) as indicated. The limitations, on the use of mild steel bars or of grade Fe 4100 as given under structural steel shall apply. Deformed Bars shall conform to IS: 1786-1979 Specifications for High strength deformed bars and wires for concrete reinforcement- enclosed as Annexure 7-A.9. Fabric reinforcement shall conform to IS: 1566-(1982) Specification for hard drawn steel wire fabrics for concrete reinforcement.

7.3.5. Tolerance on size of reinforcement bars

The tolerance on diameter of the mild steel bars shall be ± 0.5 mm for bars up to and including 25 mm with a total margin of 1mm and ±  0.75 mm for bars above 25 mm dia with total margin of 1.5 mm.  The tolerance on the diameter in the case of coiled round bars shall be ±  0.5 mm up to and including 12 mm diameter with a total margin of 1 mm. Measurement shall be taken at point sufficiently away from the ends ensuring exclusion of heavy ends.

7.3.6. Tolerance on weight

The tolerance on weight of plain and deformed round shall be ±  4 per cent with a total margin of 8 per cent for bars up to and including 8 mm diameter and ±  2.5 percent for bars over 8 mm diameter with a total margin of 5 percent.

Tolerance on weight of fabric reinforcement shall be ±  6 per cent.

7.3.7. Freedom from defects

All finished bars shall be well and cleanly rolled to the dimensions and weights specified; these shall be sound and free from cracks, surface flaws, laminations and rough, jagged and imperfect edges and other defects and shall be finished in a workman like manner.

Steel reinforcement shall be stored as to prevent distortion and corrosion.  Any reinforcement that has deteriorated or corroded or is considered defective by the engineer shall not be used in the work.  Bars of different classification, sizes and lengths shall be stored separately to facilitate use in such sizes and lengths as to minimise wastage in cutting from the standard lengths.

7.3.8. Bends and hooks forming end anchorages

Ends of plain round mild steel bars shall be bent to radius of not less than 2 diameters and the straight portion beyond the curve shall not be less than 4 diameters unless otherwise indicated. In the case of deformed bars, bends shall be made to radius of 4 times the diameter of the bar and straight portion beyond the curve shall not be less than 4 diameters, unless otherwise indicated.  Ends of deformed bars are not bent to form hooks. In the case of binders, stirrups, links, etc., the straight portion beyond end of the curve at the end shall be not less than 8 times the nominal size of the bar.

Bars specified to be formed to radii exceeding those given in Table X of IS 2502-1963 Code of practice for bending and fixing of bars for concreting, need not be bent but the required curvature may be obtained during the placing.

7.3.9. Bending of bars

Bars shall be bent to shape cold except that bars larger than 25 mm in size may be bent hot at cherry red heat (not exceeding 850 degree C).  Hot bar shall not be cooled by quenching.  A bar which shows any sign of cracks at a bend shall be rejected.

Fig. 1 Welds and Rivets

7.3.10. Splicing

Where bars required are longer than those carried in stock, splices shall be provided as far as possible, away from the section of maximum stress and be staggered. The use of short length bars shall not be permitted. IS: 456-1978 Code of practice for plain and reinforced concrete recommends

that splices in flexural members should not be at sections where the bending moment is more than 50 per cent of the moment of resistance ; and not more than half the bars shall be spliced at a section.

7.3.11. Lap splices

Lap splices shall not be used for bars larger than 36 mm dia, larger diameter bars may be welded, in cases where welding is not practicable, lapping of bars larger than 36 mm dia may be permitted in which case additional spirals shall be provided around the lapped bars. Lap length shall be not less than 30 diameters for flexural tension and direct tension and not less than 24 diameters for compression. When bars of two different diameters are to be spliced the lap length shall be calculated on the basis of diameter of the smaller bar. End bearing splices shall be used only for the bars in compression. The ends of the bars shall be square out and concentric bearing ensured by suitable devices. When larger diameters have to be welded to avoid congestion rather than lapped for splicing, the method of welding shall be as directed.  The location of staggered welds at heights or position shall be convenient for welding.

7.3.12. Spiral reinforcement

Spirals shall be provided with one and a half extra turns at both top and bottom.  Where necessary to splice the spiral it shall be done by a lap of one and a half turns or by shop welding.

7.3.13. Placing and fixing of bars

Reinforcements shall be placed in position as per detailed design drawing and shall be secured at that position.  In case of delay occurring between fixing of reinforcement and concreting, the position of the reinforcement shall be checked prior to concreting. Bars crossing each other shall be secured by binding wire (annealed) of size not less than 0.9 mm, and conforming to IS: 280-1977.  Specification for mild steel wire, in such a manner that they will not slip over each other at the time of fixing and concreting.  Every compression bar shall be tied at least in two perpendicular directions.

7.3.14. Cover blocks

Cover blocks generally of cement mortar shall be used to ensure the required cover for the reinforcement.  The mortar or concrete used for the cover blocks or rings shall be not leaner than the mortar or concrete in which they would be embedded.

7.3.15. Spacers

Where multiple rows of reinforcement are provided distances between successive rows shall be properly maintained while concreting by providing suitable spacer bars.

7.3.16. Placing reinforcements

All mill scale, loose or scaly rust, oil and grease or any coating that will destroy or reduce bond shall be thoroughly cleaned off the steel reinforcement with a stiff wire brush or other approved means before it is placed in forms.  Steel reinforcement when placed in the forms shall be properly braced, supported, or otherwise held firmly in position so that placing and ramming / vibrating of concrete does not displace it. It shall be ensured that all the reinforcement can be properly placed.  Congestion of steel shall be avoided at points where members intersect.

7.3.17. Tolerance in placing of reinforcement

Unless otherwise indicated, reinforcement shall be placed within following tolerance.

(a) For effective depth 200 mm or less ± 10 mm (b) For effective depth more than 200 mm or ± 15 mm

The cover shall in no case be reduced by more than 1/3 of specified cover or 5 mm whichever is less.

7.3.18. Steel wire fabric reinforcement

Hard drawn steel fabric shall conform to IS 1566-1982 – Specification for hard drawn steel wire fabric for concrete reinforcement, MESH size, weight, size of wire for square and oblong welded shall be indicated. The fabric shall be formed by spacing the main and the cross wire, which shall be fixed at the point of intersection by electric welding.

Since fabric is supplied in long rolls it is rarely necessary to have a joint of the main wires.  In structural slab laps in regions, of maximum stress shall be avoided. When splicing of welded wire fabric is to be carried out, lap splices of wires shall be made so that overlap measured between the extreme cross wires shall be not less than the spacing of cross wires plus 10 cm. For edge laps a lap of 5 cm shall be provided.

7.3.19. Welding of reinforcement

Welding of bars where indicated or agreed to by the engineer, in writing, in lieu of lapping shall be done in accordance with IS: 2751-1979, Code of practice for welding of concrete construction. Welding in general shall be done as described for structural steel work.

Bars up to and including 20 mm dia shall be lap welded and those larger than 20 mm dia shall be butt welded.  In case of lap welds, the length of lap shall be five times the dia or 100 mm whichever is greater. The throat thickness shall not be less than 3 mm for bars up to 16 mm dia and 5 mm for bars over 16 mm dia and up to 20 mm dia.

7.3.20. Butt welding

Where it is not possible to rotate bars for welding in flat positions the axis of the bars shall be horizontal and the respective axis of welds shall be vertical.  The edge preparation for inclined bars shall be such that welding is done only on sides.  All the bars to be butt welded shall be aligned and set up in position with their axis in one straight line.  This may be done in a jig or by means of a clamp or by using guides.  Rotation of the bars shall be avoided, until they are adequately welded.

7.3.21. Lap welding

Edge preparation is not necessary for lap welds.

7.3.22. Finish

The profile of the welds shall be uniform, slightly convex and free from overlap at the toes of the welds.  The weld face shall be uniform in appearance throughout its length.  The welded joint shall be free from undercut.  The joints in the weld run shall be as smooth as practicable and shall show no pronounced hump or crater in the weld surface. The surface of the weld shall be free from porosity, cavities and trapped slag.

7.4. SPECIFICATIONS FOR STEEL WORK IN SINGLE SECTION FIXED INDEPENDENTLY WITH CONNECTING PLATE

7.4.1. The steel work in single sections of R. S. joists, flats, Tees Angles fixed independently with or without connecting plate, is described in these clauses.

7.4.2. Fabrication

The steel sections as specified shall be straightened and cut square to correct lengths and measured with a steel tape.  The cut ends exposed to view shall be finished smooth.  No two pieces shall be welded or otherwise jointed to make up the required length of a member.

All straightening and shaping to form, shall be done by pressure.  Bending or cutting shall be carried out in such a manner as not to impair the strength of the metal.

7.4.3. Painting

All surfaces which are to be painted, oiled or otherwise treated shall be dry and thoroughly cleaned to remove all loose scale and loose rust. Surfaces not in contact but inaccessible after shop assembly, shall receive the full specified protective treatment before assembly.  This does not apply to the interior of sealed hollow sections.  Part to be encased in concrete shall not be painted or oiled.  A priming coat of approved steel primer i.e. red oxide zinc chrome primer conforming to IS:  2074 shall be applied before any member of steel structure are placed in position or taken out of workshop.

7.4.4. Erection

Steel work shall be hoisted and placed in position carefully without any damage to itself and other building work and injury to workmen. Where necessary mechanical appliances such as lifting tackle winch etc shall be used. The suitability and capacity of all plant and equipment used for erection shall be to the satisfaction of the engineer.

7.4.5. Measurements

The work as fixed in place shall be measured in running metres correct to a millimeter and weights calculated on the basis of standard tables correct to the nearest kilogram.

Unless otherwise specified, weight of cleats, brackets, packing pieces, bolts, nuts, washers, distance pieces, separators, diaphragm,  gussets (taking overall square dimensions) fish plates, etc., shall be added to the weight of respective items.  In riveted work, allowance is to be made for weight of rivet

heads. Unless otherwise specified an addition of 2.5% of the weight of structure shall be made for shop and site rivet heads in riveted steel structures.

No deduction shall be made for rivet / or bolt holes (excluding holes for anchor or holding down bolts).

Deduction in case of rivet or bolt hole shall however be made if its area exceeds 0.02 sqm.

The weight of steel sheets, plates and strips shall be taken from relevant Indian Standards based on 7.85 kg/m2 for every millimetre sheet thickness.  For rolled sections, steel rods and steel strips, weight given in relevant Indian Standards shall be used.

7.4.6. Rate

Rate includes the cost of labour and materials required for all the operations described above.

7.5. SPECIFICATIONS FOR STEEL WORK RIVETTED AND BOLTED BUILT UP SECTIONS.

The steel work in built up sections (Riveted and bolted such as in trusses, framed work etc. is specified in this clause.

7.5.2. Laying out

A figure of the steel structure to be fabricated shall be drawn on a level platform to full scale.  This may be done in full or in parts, as shown on drawings or as directed by the engineer.  Steel tape shall be used for measurements.

7.5.3. Fabrication

Fabrication shall generally be done as specified in IS:  800-1984.

In major works or where so specified, shop drawings giving complete information for the fabrication of the component parts of the structure including the location, type, size, length and details or rivets, bolts or welds, shall be prepared in advance of the actual fabrication and approved by the engineer. The drawings shall indicate the shop and field rivets, bolts and welds.  The steel members shall be distinctly marked or stenciled with paint with the identification marks as given in the shop drawings.

Great accuracy shall be observed in the fabrication of various members, so that these can be assembled without being unduly packed, strained or forced into position and when built up, shall be true and free from twist, kinks, buckles or open joints.

Wooden or metal sheet templates shall be made to correspond to each member, and position of rivet holes shall be marked accurately on them and holes drilled. The templates shall then be laid on the steel members, and holes for riveting and bolting marked on them. The ends of the steel members shall also be marked for cutting as per required dimensions.  The base of steel columns and the positions of anchor bolts shall be carefully set out at the required location.

The steel section shall be straight or be straightened or flattened by pressure unless required to be of curvilinear for and shall be free from twists.  These shall be cut square either by shearing or sawing to correct length and measured by steel tape.  No two pieces shall be welded or joined to make up for the required length of member.

7.5.4. Making holes

Holes through more than one thickness of material for members, such as compound stanchion and girder flanges shall, where possible, be drilled after the members are assembled and tightly clamped or bolted together.  Punching may be permitted before assembly, provided the holes are punched 3 mm less in diameter than the required size and reamed after assembly to the full diameter.  The thickness of material punched shall be not greater than 16 mm.

7.5.5. Rivet holes

The diameter for rivets and black holes shall be taken as the nominal diameter of a rivet plus 1.5 mm for rivets of nominal diameter less than or equal to 25 mm and 2.0 mm for rivets of nominal diameter exceeding 25 mm, unless specified  otherwise.  Holes for turned and fitted bolts shall be drilled or reamed large by 0.2 to 8 mm depending upon the dia. of bolts.

Holes shall have their axis perpendicular to the surface bored through.  The drilling or reaming shall be free from burrs, and the holes shall be clean and accurate. Holes for rivets and bolts shall not be

formed by gas cutting process. Holes for counter sunk bolts shall be made in such a manner that their heads sit flush with the surface after fixing.

7.5.6. Assembly

Before making holes in individual members, for fabrication and steel work intended to be riveted or bolted together shall be assembled and clamped properly and tightly so as to ensure close abutting, or lappling of the surfaces of the different members.  All stiffeners shall bear tightly both at top and bottom without being drawn or caulked. The abutting joints shall be cut or dressed true and straight, and fitted close together.

Web plates of girders, which have no cover plates, shall have their ends flush with the tops and angles unless otherwise required.  The web plates when spliced shall have clearance of not more than 5 mm. The erection clearance for cleated ends of members connecting steel to steel shall preferably be not greater than 1.5 mm.  The erection clearance at the ends of beams without web cleats shall not be more than 3 mm at each end but where for practical reasons, greater clearance is necessary suitably designed seating shall be provided.

Column splices and butt joints of struts and compression members depending on contact for stress transmission shall be accurately, machined and close butted over the whole section.  In column caps and bases, the ends of shafts together with the attached gussets, angles, channels etc. after riveting together shall be accurately machined so that the parts connected, butt against each other over the entire surfaces of contact.  Connecting angles or channels shall be fabricated and placed in position with great accuracy so that they are not unduly reduced in thickness by machining.

The ends of all bearing stiffeners shall be machined or grounded to fit tightly both at top and bottom.

7.5.7. Riveting

Rivets shall be used, where the connection is such that slip under load has to be avoided.

7.5.8. Preliminaries before riveting

Members to be riveted shall have all parts firmly drawn and held together before and during riveting, and special care shall be taken in this respect for all single riveted connections. For multiple riveted connections, a service bolt shall be provided in every third or fourth hole.

7.5.9. Process of riveting

The riveting shall be carried out by using machines of the steady pressure type.  However, where such facilities are not available hand riveting may be permitted by the engineer. The rivets shall be heated red hot, care being taken to control the temperature of heating so as to not to burn the steel.  Rivets of diameter less than 10 mm may be driven cold. Rivets shall be finished neat, with heads full and of equal size. The heads shall be central on shanks and shall grip the assembled members firmly. All loose, burnt, or badly formed rivets with eccentric or deficient heads shall be cut out and replaced.  In cutting out rivets, care shall be taken so as not to injure the assembled members.  Caulking and recupping shall not be permitted.

For testing rivets, a hammer weighing approx. 0.25 kg shall be used and both heads of the rivet (specially the machine head) shall be tapped.  When so tested, the rivets shall not give a hollow sound and a jar.  Where so specified, other tests shall be carried out to ensure the soundness of rivets. All rivets heads shall be painted with approved steel primer paint within a week of their fixing.

7.5.10. Bolting

The nominal length of the bolt shall be the distance from the underside of the head to the further end of the shank.  The nominal diameter of the bolt shall be the diameter at the shank above the screwed threads, Bolts, nuts and washers shall be thoroughly cleaned and dipped in double boiled linseed oil, before use.  All bolts heads and nuts shall be hexagonal unless specified otherwise.  The screwed threads shall conform to IS: 1363 and the threaded surface shall not be tapered.  The bolts shall be of such length as to project at least two clear threads beyond the nuts when fixed in position, and these shall fit in the holes without any shake.  The nuts shall fit in the threaded ends of bolts properly.

Where necessary, washers shall be tapered or otherwise suitably shaped to give the heads and nuts of bolts a satisfactory bearing.  The threaded portion of each bolt shall project through the nut at least two thread.  In all cases where the full bearing area of the bolt is to be developed, the bolt shall be provided with a washer of sufficient thickness under the nuts to avoid any threaded portion of the bolt being within the thickness of the parts bolted together.

Where there is a risk of the nuts being removed or becoming loose due to vibrations or reversal of stresses, these shall be secured from slackening by the use of lock nuts, spring washers as directed by the engineer.

7.5.11. Erection

Steel work shall be hoisted and erected in position carefully, without any damage to itself, other structures and equipment and injury to workmen.  The method of hoisting and erection proposed to be adopted by the contractor shall be got approved from the engineer in advance.  The contractor however shall be fully responsible for the work being carried out in a safe and proper manner without unduly stressing the various members and proper equipment such as derricks, lifting tackles, winches, ropes etc. shall be used. The work may be erected in suitable units as may be directed by the engineer.  Fabricated members shall be lifted at such points as to avoid deformation or excessive stress in members. The structure or part of it placed in position shall be secured against over –turning or collapse by suitable means. During execution, the steel work shall be securely bolted or otherwise fastened and when necessary temporarily braced to provide for all loads to be carried safely by the structure during erection including those due to erection equipment and its operations. The steel work shall be placed in proper position as per approved drawing, final riveting or permanent bolting shall be done after proper alignment has been checked and confirmed.

Trusses shall be lifted only at nodes. The trusses above 10 mm in span not be lifted by slinging at two mid points of rafters, which shall be temporary braced by a wooden member of a suitable section. After the trusses are placed in position, purlins and wind bracings shall be fixed as soon as possible.

The end of the truss which faces the prevailing winds shall be fixed with holding down bolts, and the other end kept free to move.  In case of trusses of spans up to 10 m the free end of the truss shall be laid on lead sheet or steel plate as per design, and the holes for holding down bolts shall be made in the form of oblong slots so as to permit the free movements of the truss end.  For large spans the truss shall be provided with proper bearing as per design.

Columns and stanchions shall be erected truly vertical with the necessary cross bracing etc. and the base shall be properly fixed with the foundation concrete by means of anchor bolts etc. as per drawing.

Anchor bolts to be placed in the concrete foundation should be held in position with a wooden template. At the time of concreting anchor bolt locations shall be provided with suitable timber mould or pipe sleeve to allow for adjustment which shall be removed after initial setting of concrete. The spaces left around anchor bolts shall be linked to a stopping channel in the concrete leading to the side of the pedestal and on the underside of the base plate to allow the spaces being grouted up after the base plate is fixed in the position along with the column footing. Grouting shall be of cement mortar 1:3 (1 cement 3 coarse sand) or as specified.

7.5.12. Bedding of column, stanchions etc.

Bedding shall not be carried out until the steel work has been finally leveled, plumbed and connected together. The stanchion shall be supported on steel wedges and adjusted to make the column plumb. For multistoreyed buildings, the bedding shall not be done until sufficient number of bottom lengths of stanchions have been properly lined, leveled and plumbed and sufficient floor beams are fixed in position. The base plates shall be wedged clear of the bases by M.S. wedges and adjusted where necessary to plumb the columns. The gaps under the base plate may be made up to 25 mm shall then be pressure grouted with cement grouts.

With small columns, if permitted by the engineer, the column base shall be floated on a thick cement grout on the concrete pedestal.  The anchor bolt holes in the base plate may be made about 10 to 15 mm larger than the bolts.  In such cases suitable washers shall be provided.

7.5.13. Painting

Before the members of the steel structure are placed in position or taken out of the workshop these shall be painted as specified.

7.5.14. Measurements

The work as fixed in place shall be measured in running metres correct to a millimetre and their weight calculated on the basis of standard tables correct to the nearest kilogram.

Unless otherwise specified, weight of cleats, brackets, packing pieces, bolts nuts, washers, distance pieces, separators diaphragm gussets (taking overall square dimensions) fish plates, etc. shall be added to the weight of respective items.  No deductions shall be made for skew cuts.  In riveted work, allowance is to be made for weight of rivet heads.  Unless otherwise specified an addition of 2.5% of the weight of structure shall be made of shop and site rivet heads in riveted steel structures.  No deduction shall be made for rivet/or bolt holes (excluding holes for anchor or holding down bolts).  Deduction in case of rivet or bolt hole shall, however, is made if its area exceeds 0.02 m2.

The weight of steel sheet and strips shall be taken from relevant Indian Standards based on 7.85 kg/m2 for every millimeter sheet thickness. For rolled sections, steel rods and steel strips, weight given in relevant Indian Standards shall be used.

7.5.15. Rate

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

7.6. SPECIFICATIONS FOR STEEL WORK IN WELDED BUILT UP SECTION

The steel work in built up sections (welded) such as in trusses, framed work etc. is specified in this clause.

7.6.2. Laying out

A figure of the steel structure to be fabricated shall be drawn on a level platform to full scale.  This may be done in full or in parts, as shown on drawings or as directed by the engineer.  Steel tape shall be used for measurements.

7.6.3. Fabrication

Straightening, shaping to form, cutting and assembling, shall be as per 7.5.3 as far as applicable, except that the words “riveted or bolted” shall be read as “welded” and holes shall only be used for the bolts used for temporary fastening as shown in drawings.

7.6.4. Welding

Welding shall generally be done by electric arc process as per IS:  816 and IS:  823. The electric arc method is usually adopted and is economical.  Where electricity for public is not available generators shall be arranged by the contractor at his own cost unless otherwise specified.  Gas welding shall only be resorted to using oxyacetylene flame with specific approval of the engineer.  Gas welding shall not be permitted for structural steel work.  Gas welding requires heating of the members to be welded along with the welding rod and is likely to create temperature stresses in the welded members. Precautions shall therefore be taken to avoid distortion of the members due to these temperatures stresses.

The work shall be done as shown in the shop drawings which should clearly indicate various details of the joint to be welded, type of welds, shop and site welds as well as the types of electrodes to be used.  Symbol for welding on plane and shops drawings shall be according to IS:  813.

As far as possible every effort shall be made to limit the welding that must be done after the structure is erected so as to avoid the improper welding that is likely to be done due to heights and difficult positions on scaffolding etc., apart from the aspect of economy.  The maximum dia of electrodes for welding any work shall be as per IS: 814 and appendix “B” of IS:  823.  Joint surfaces which are to be together shall be free from loose mill scale, rust, paint, grease or other foreign matter, which adversely affect the quality of weld and workmanship.

7.6.5. Precautions -All operations connected with welding and cutting equipment shall conform to the safety requirements given in IS:  818 for Safety Requirements and Health Provisions in electric and gas welding and cutting operations. Operation, Workmanship and Process of Welding shall be as described in this section. Inspection and testing of welds shall be as per IS: 822.

7.6.6. Assembly

Before welding is commenced, the members be welded shall first be brought together and firmly clamped or tack welded to be held in position.  The temporary connection has to be strong enough to hold the parts accurately in place without any disturbance. Tack welds located in places where final welds will be made later shall conform to final weld in quality and shall be cleaned off before final weld is made.

7.6.7. Erection

The specifications shall be as described except that while erecting a welded structure adequate means shall be employed for temporary fastening of the members together and bracing the frame work until the joints are welded.  Such means shall consists of erection bolts, tack welding or other positive devices imparting sufficient strength and stiffness to resist all temporary loads and lateral forces including wind.  Owing to the small number of bolts ordinarily employed for joints which are to be welded, the temporary support of heavy girders carrying columns shall be specially attended. Different members which shall be fillet welded, shall be brought into as close contact as possible. The gap due to faulty workmanship or incorrect fit if any shall not exceed. 1.5 mm if gap exceeds 1.5 mm or more occurs locally the size of fillet weld shall be increased at such position by an amount equal to the width of the gap.

7.6.8. Painting

Before the member of the steel structures are placed in position or taken out of the workshop these shall be painted as specified.

7.6.9. Measurements

The mode of measurements shall be the same as specified except that weight of welding material shall not be added in the weight of members for payment and nothing extra shall be paid for making and filling holes for temporary fastening of members during erection before welding.

7.6.10. Rate

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

7.7. SPECIFICATIONS FOR STEEL COLLAPSIBLE GATES (Fig.2)

7.7.1. These shall be of approved manufacture and shall be fabricated from the mild steel sections.

The gates shall consist of double or single collapsible gates depending on the size of the opening.  These shall consists of vertical double channels each 20 x 10 x 2mm. at 10 cm centres braced with flat iron diagonals 20 x 5 mm and top and bottom rails of T-iron 40 x 40 x 6 mm at 3.5 kg/m with 40 mm dia. ball bearings in every fourth double channel, unless otherwise specified. Wherever collapsible gate is not provided within the opening and fixed along the outer surface, T-iron at the top may be replaced by flat iron 40 x 10 mm.

The collapsible gate shall be provided with necessary bolts and nuts, locking arrangement, stoppers and handles.  Any special fittings like spring, catches and locks, shall be so specified in the description of item where so required.  The gate shall open and close smoothly and easily.

7.7.2. Fixing

T-iron rails shall be fixed to the floor and to the lintel at top by means of anchor bolts embedded in cement concrete of floor and lintel.  The anchor bolts shall be placed approximately at 45 cm centres alternatively in the two flags of the T-iron.  The bottom runner (T-iron) shall be embedded in the floor and proper groove shall be formed along the runner for the purpose.  The collapsible shutter shall be fixed at sides by fixing the end double channels with T-iron rails and also by hold – fasts bolted to the end double channel and fixed in masonry of the side walls on the outer side.  In case the collapsible shutter is not required to reach the lintel, beam or slab level,  a Tee – section suitably, designed may be fixed at the top, embedded in masonry and provided with necessary clamps and roller arrangement at the top.  All the adjoining work damaged in fixing of gate shall be made good to match the existing work, without any extra cost.

Fig. 2 Collapsible steel gate

7.7.3. Painting

All the members of the collapsible gate including T-iron shall be thoroughly cleaned off rust, scales, dust etc and given a priming coat of approved steel primer i.e., red oxide zinc chrome primer conforming to IS: 2074 before fixing them in position.

7.7.4. Measurements

The height and breadth shall be measured correct to a cm.  The height of the gate shall be measured as the length of the double channels and breadth from outside to outside of the end fixed double channels in open position, of the gate.  The area shall be calculated in square metres, correct to two places of decimal.

7.7.5. Rate

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

7.8. SPECIFICATIONS FOR MILD STEEL SHEET SLIDING SHUTTER

7.8.1. These shall be manufactured as per drawings and specifications.  These shall be fabricated from mild steel sheets.

7.8.2. The shutters shall be double or single leaf shutter as specified.  The shutters shall be fabricated of specified size of M .S. angle iron frame diagonally braced with the same size of M. S. angle and riveted together with 3 mm gusset plate at junction to form a rigid flame.  M. S. sheet of 1 mm thickness or as specified shall be fixed to the frame with rivets, as approved by the engineer. These shall also be provided with top and bottom guide rails of specified size angles or T-irons and 25 mm diameter pulley or with 25 mm diameter ball bearing at the bottom and guide block with steel pulleys at the top.  The shutters shall also be provided with locking arrangement, handles, stoppers, and holdfasts, other fittings as specified in the description of the item.

The guide rails shall be sufficiently long and continued along the wall on both ends – so that the sliding shutters can rest against the walls, giving full opening when so required.

7.8.3. Fixing

The guide rails shall be fixed to the floor by means of anchor bolts embedded in the cement concrete floor.  The steel section at the top shall be suitably supported from the walls. Tow channel sections shall be suitably fixed vertically below the extreme clamps in the wall and floor to avoid the shutter from going out of the supports at top and bottom. A suitable clamping arrangement will be provided at either end of the opening to avoid the shutters from rolling back into the opening.

All the adjoining work damaged in fixing shall be made good to match the existing work.

7.8.4. Painting

All members of the sliding shutters including fitters shall be thoroughly cleaned of rust, scales, dust etc., and given a priming coat of approved steel primer i.e. Red oxide zinc chrome primer confirming to IS: 2074 before fixing them in position.

7.8.5. Measurements

The height and width shall be measured correct to a cm and its area for payment shall be calculated in square metres correct to two places of decimal.  The height of the shutter shall be measured from outside to outside of the guide rail and width out side to outside of the shutter including the vertical position channels in sides, when closed.

7.8.6. Rate

The rate shall include the cost of materials and labour involved in all the operations described above.  It also includes the cost of the full length of guide rails.

7.9. SPECIFICATIONS FOR MILD STEELSHEET SHUTTERS

7.9.1. These shall be manufactured as per drawing and specifications. These shall be fabricated from mild steel sheets and angle iron.

The doors shall be provided as double leaf shutters unless otherwise specified.  The shutters shall be fabricated with frame of M. S. angle 40 x 10 x 6 mm at 3.5 kg/meter and two diagonal braces of the same section as shown in Fig. 3 unless otherwise specified.  The frame shall be riveted and/or welded at the junctions. Wherever riveting shall be done 3 mm thick gusset plate shall be provided at the junctions, M. S. sheet of 1 mm thickness or as specified, shall be fixed to the frame with rivets or welds as approved by the engineer.

Alternatively, the diagonal bracing may be replaced by one horizontal and two cross flats 30 x 6 mm as shown in Fig. 3 unless otherwise specified.

The outer frame shall be provided with cleats made of section 40 x 10 mm and bent in the shape of angle cleats with one arm 150 mm long and the other arm 50 mm long and fixed to the angle iron frame of the door with two 12 mm dia bolts and nuts.  For door up to 2.40 m height, two angles cleats per door shall be provided.

The cleat shall have a vertical leg of 150 mm which shall be fixed with frame and horizontal leg of about 50 mm which shall be provided with a hole of 24 mm dia and fixed in the projected pin of the pin clamp.

7.9.2. Fittings and fixtures

The shutter shall be fixed to the wall masonry with four pin clamps (pin ties) where the height of the shutter is up to 2.4 m. Each pin clamp shall consist of 50 x 6 mm flat iron 45 cm long bend and forked

at one end and provided with 20 mm diameter M. S. pin on the other.  The pin shall be firmly riveted or welded to the pin clamp, the other end of which shall be embedded in masonry by means of cement concrete block 40 x 20 x 20 cm of 1:3:6 mix (1 cement 3 coarse sand 6 graded stone aggregate 20 mm nominal size).  It shall be so placed that bottom pin shall face upwards and top downwards in order that the gate may not be removed by lifting over pins.

 Fig. 3 Typical M.S. sheet shutters

One hook with eye 45 cm long of 10 mm diameter shall be provided for each shutter to keep it fixed in open position.  The hook shall be fixed in wall masonry with wooden block and the eye shall be fixed to 6 mm thick M. S. plate as staple and fixed in the shutter frame with rivet or weld.

A cement concrete block 15 x 10 x 20 cm in 1:2:4 (1 cement  2 coarse sand  4 grades stone aggregate of 20 mm nominal size) mix shall be embedded in the floor or at junction of two shutters so that door shutter open only on the outside and not on the inside.

The shutters shall also be provided with locking arrangement and two handles of the shape and pattern as approved by the engineer.

7.9.3. Painting

 All the members of the door including angle iron shall be thoroughly cleaned off rust, scales, dust etc. and given a priming coat of approved steel primer i.e. Red oxide Zinc chrome primer confirming to IS:  2074 before fixing them in position.

7.9.4. Measurements

The width and height of shutters shall be measured to the nearest cm.  The area shall be calculated in square meter correct to two places of decimal.

7.9.5. Rate

The rate shall include the cost of materials and labour involved in all the operations described above.  Nothing extra shall be paid for cement concrete blocks or wooden blocks nor did anything deduct for these from the measurement of the masonry wall.

7.10. SPECIFICATIONS FOR STEEL ROLLING SHUTTERS

7.10.1. Rolling shutters shall conform to IS: 6247.  These shall include necessary locking arrangement and handles etc.  These shall be suitable for fixing in the position as specified i.e. outside or inside on or below lintel or between jambs of the opening.  The door shall be either push and pull type or operated with mechanical device supplied by the firm.  Shutters up to 10 sq. metres shall be of push and pull type and shutters with an area of over 10 sq.metre shall generally be provided with reduction gear operated by mechanical device with chain or handle, if bearings are specified for each of operation, these shall be paid for separately.

7.10.2. Shutter

The shutter shall be built up of interlocking lath section formed from cold rolled steel strips.  The thickness of the sheets from which the lath sections have been rolled shall be not less than 0.90 mm for the shutters up to 3.5 m width and not less than 1.20 mm for shutters above 3.5 m width.  Shutters above 9 meters in width should be divided in 2 parts with provision of one middle fixed or movable guide channel or supported from the back side to resist wind pressure.  The lath section shall be rolled so as to have interlocking curls at both edges and a deep corrugation at the centre with a bridge depth of not less than 12 mm to provide sufficient curtain of stiffness for resisting manual pressures and normal wind pressure.  Each lath section shall be continuous single piece without any welded joint. When interlocked, the lath sections shall have a distance of 75 mm rolling centers.  Each alternate lath section shall be fitted with malleable cast iron or mild steel clips securely riveted at either ends, thus locking the lath section at both ends and preventing lateral movement of the individual lath sections. The clips shall be so designed as to fit the contour of the lath sections.

7.10.3. Spring

The spring shall be of coiled type.  The spring shall be manufactured from high tensile spring steel wire or strips of adequate strength conforming to IS:  4454-Part I.

7.10.4. Roller and brackets

The suspension shaft of the roller shall be made of steel pipe conforming to heavy duty as per IS: 1161.  For shutter up to 6 meter width and height not exceeding 5 meter, steel pipes of 50 mm nominal bore shall be used.  The shaft shall be supported on mild steel brackets of size 375 x 375 x 3.15 mm for shutters up to a clear height of 3.5 meter.  The size of mild steel brackets shall be 500 x 500 x 10 mm for shutters of clear height above 3.5 m up to 6.5 m. The suspension shaft clamped to the brackets shall be fitted with rotable cast iron pulleys to which the shutter is attached.  The pulleys and pipe shaft shall be connected by means of pretension helical springs to counter balance the weight of the shutter and to keep the shutter in equilibrium in any partly open position. When the width of the opening is greater than 3.5 meter the cast iron pulleys shall be interconnected with a cage formed out of mild steel flats of at least 32 x 6 mm and mild steel dummy rings made of similar flats to distribute the torque uniformly. Self aligning two row ball bearings with special cast iron casings shall be provided at the extreme pulley and caging rings shall have a minimum spacing of 15 mm and at least 4 number flats running throughout length of roller shall be provided.

In case of shutters of large opening with mechanical device for opening the shutter the roller shall be fitted with a pinion wheel at one end which in contact with a worm fitted to the bracket plate, caging and pulley with two ball bearing shall be provided.

7.10.5. Guide channel

The width of guide channel shall be 25 mm the minimum depth of guide channels shall be as follows

Clear width of shutters

Depth of guide channel

Up to 3.5 m

65 mm

3.5 m up to 8 m

75 mm

8 m and above

100 mm

The gap between the two legs of the guide channels shall be sufficient to allow the free movements of the shutter and at the same time close enough to prevent rattling of the shutter due to wind.

Each guide channel shall be provided with a minimum of three fixing cleats or supports for attachment to the walls or column by means of bolts or screws.  The spacing of cleats shall not exceed 0.75 m.  Alternatively, the guide channels may also be provided with suitable dowels, hooks or pins for embedding in the walls.

The guide channels shall be attached to the jambs, plumb and true either in the overlapping fashion or embedded in grooves, depending on the method of fixing.

7.10.6. Cover

Top cover shall be of mild sheets not less than 0.90 mm thick and stiffened with angle or flat stiffeners at top and bottom edges to retain shape.

Lock plates with sliding bolts, handles and anchoring rods shall be as per IS: 6247.

7.10.7. Fixing

The arrangement for fixing in different situations in the opening shall be as per IS:  6247.

Brackets shall be fixed on the lintel or under the lintel as specified with rawl, plugs, and screws bolts etc.  The shaft along with the spring shall then be fixed on the brackets.

The lath portion (shutter) shall be laid on ground and the side guide channels shall be bound with ropes etc.  The shutter shall then be placed in position and top fixed with pipe shaft with bolts and nuts.  The side guide channels and cover frames shall then be fixed to the wall through the plate welded to the guides.  These plates and bracket shall be fixed by means of steel screws bolts, and rawl plugs concealed in plaster to make their location invisible.  Fixing shall be done accurately in a workman like manner that the operation of the shutter is easy and smooth.

7.10.8. Measurements

Clear width and clear height of the opening for rolling shutter shall be measured correct to a mm.  The clear distance between the two jambs of the opening shall be clear width and the clear distance between the sill and soffit (bottom of lintel) of the opening shall be the clear height.

The area shall be calculated in square metres correct to two places of decimal.

7.10.9. Rate

The rate shall include the cost of materials and labour involved in all the operations described above including cost of top cover and spring except ball bearing and mechanical device of chain and crank operation, which shall be paid for separately.

7.11. SPECIFICATIONS FOR STEEL ROLLING GRILLS.

Rolling grill is meant to provide visibility or ventilation or both, the degree of protection and safety is less as compared to a rolling shutter.  The situations where a certain amount of ventilation combined with safety is required rolling shutter-cum-grill  may be provided in which the rolling shutter may have a rolling grill portion either at the top or at the bottom or at both places.   In addition, the rolling grill portion may also be provided in the middle of the shutter.  The total height of the grill portion in all the segments of rolling shutter –cum – grill shall not exceed 1.0 m and the height of the grill portion in any individual segment shall not be more than 0.5 m.

Rolling grills are similar in design, construction and operation of rolling shutters and all the provisions shall be applicable to rolling grills except in respect of the shutter portion, and shall conform to IS:  6248-1979.

7.11.2. Shutters

Rolling grill shutter and the rolling grill portion of the rolling shutter – cum – grill shall be fabricated with 8 mm diameter mild steel round bars.  Straight bars and bars bent to the required profile are placed alternatively and held in position with 20 mm wide and 5 mm thick mild steel flat links.  Straight bars shall be spaced not exceeding 150 mm centre to centre and the bars bent to required profile shall be placed symmetrically between two consecutive straight bars. Unless otherwise specified or directed by the engineer, bars placed alternatively with straight bars shall be bent to form a corrugated profile such that the pitch of the corrugation is 100 to 120 mm and the depth of corrugation is 80 to 100 mm.  All the bent bars shall have uniform profile.  Straight bar along with the adjoining bent bars on it both sides shall be held in position by passing the bars through holes in the links.  Each link shall have three holes and the length of the links shall be such that the distance from the centre of the hole to the nearest edge of the flat is not less than the diameter of the hole.  The corner of the links shall be rounded.  All links shall be of uniform size and shape.  The spacing of the links measured along the straight bar shall be of uniform size and shape.  The spacing of the links measured along the straight bar shall be the same as centre to centre distance between two consecutive crests/troughs of the bars bent to the required profile.  Each bar and link shall be a continuous single piece without any joint.

7.11.3. Measurement and rate

The measurements and rate shall be as specified in 7.9.8.  In case of Rolling Shutter-cum-Grill, where the area of the grill portion is half or less than  half the area of opening, it shall be measured and paid as rolling shutter and where the area of grill portion is more than half the area of opening, it shall be measured and paid as rolling grill.

7.12. SPECIFICATIONS FOR STEEL DOOR, WINDOWS, VENTILATORS AND COMPOSITE UNITS (FIG. 4)

7.12.1. Steel Doors - Hot rolled steel sections for fabrication of steel doors, windows, ventilators and fixed lights shall conform to IS: 7452-1990.  Shapes weights and designations of hot rolled sections shall be as per IS: 7452-1990.  Tolerance in thickness of the sections shall be + 0.2 mm.  The steel doors, windows, ventilators and composite units shall be got fabricated in workshop approved by the engineer. The steel doors and windows shall be according to the specified sizes and design.  The size of doors and windows shall be calculated, so as to allow 1.25 cm clearance on all the four sides of opening to allow for easy fitting of doors windows and ventilators into opening.  The actual sizes of doors, windows and ventilators shall not vary by more than + 1.5 mm from those given in the drawing.

7.12.2. Fabrication

Frames - Both the fixed and opening frames shall be made of sections which have been cut to length and mitred.  The corner of fixed and opening frames shall be welded to form a solid fused welded joint conforming to the requirements given below. All frames shall be square and flat.  The process of welding adopted shall be flash butt welding.  The section of glazing shall be tennoned and riveted into the frames and where they intersect the vertical tie shall be broached and horizontal tee threads through it, and the intersection closed by hydraulic pressure.

7.12.3. Requirements of welded joints

i)  Visual inspection test

When two opposite corners of the frame are cut, paint removed and inspected, the joint shall conform to the following ;

  1. Welds should have been made all along the place of meeting the numbers and tack welding shall not be permitted.(b) Welds should have been properly grounded and ( c )Complete cross section of
  2. the corner shall be checked up to see that the joint is completely solid and there are no cavities visible.

ii) Micro and macro examinations

From the two opposite corners obtained for visual test, the flanges of the sections shall be cut with the help of saw.  The cut surface of the remaining portions shall be polished, etched and examined.  The polished and etched faces of the weld and the base metal shall be free from cracks and reasonably free from under cutting, overlaps, gross porosity and entrapped slag.

iii) Fillet weld test

The fillet weld in the remaining portion of the joint shall be fractured by hammering.  The fractured surfaces shall be free from slag inclusion porosity, crack penetration defects and fusion defects.

7.12.4. Door

The hinges shall be of 50 mm projecting type. Non projecting type hinges may also be used if approved by the engineer.  The hinge pin shall be of electro galvanized steel or aluminium alloy of suitable thickness and size.  Door handles shall be approved by the engineer.  A suitable latch locks for door openable both from inside and outside shall be provided.

In the case of double doors, the first closing leaf shall be left hand leaf locking at the door from the push side.  The first closing shutter shall have a concealed steel bolt at top and bottom. The bolts shall be so constructed as not to work loose or drop by its own weight.

Single and double shutter door be provided with a three way bolting device.  Where the device is provided in the case of double shutters, concealed brass or steel bolts shall not be provided.

7.12.5. Steel windows

a) For fixed windows, the frames shall be fabricated as per specified standards

b)  Side hung windows

For fixing steel hinges, slots shall be cut in the fixed frame and hinges inserted inside and welded to the frame at the back.  The hinges shall be of projecting type with thickness not less than 3.15 mm and length not less than 65 mm and width not more than 25 mm.  No projecting type hinges may also be allowed if approved by the engineer.  The diameter of hinges pins shall not be less than 6 mm. The hinge pin and washer shall be of galvanized steel or aluminium alloy of suitable thickness.

For fixing hinges to inside frame, the method described above may be adopted but the weld shall be cleaned, or the holes made in the inside frame and hinge riveted.

The handle of side shutters shall be pressed brass, cast brass, aluminium or steel protected against rusting and shall be mounted on a steel plate.  Thickness of handle shall not be less than 3 mm in case of steel or brass and 3.5 mm in case of aluminium.  The handle plate shall be welded, screwed and / or riveted to the opening frame in such a manner that it should be fixed before the shutter is glazed and should not be easily removable after glazing.

The handle shall have a two point nose which shall engage with a brass or aluminium alloy striking plate on the fixed frame in a slightly opened position as well as closed position. The boss of handle shall incorporate a friction device to prevent the handle from dropping under its own weight and the assembly shall be so designed that the rotation of the handle may not cause it to unscrew from the pin.The height of the handle plate in each type standard windows will be as specified. Otherwise it shall be at a height of 3/8 of the height of shutter, from its bottom. The strike plate shall be so designed and fixed in such a portion in relation to the handle that with the later bearing against its stop, there shall be adequately tight fit between the casement and outer frames.

In case where no friction type hinges are provided, the windows shall be fitted with peg stays which shall be either of black oxidised steel, pressed or cast brass or as specified, 300 mm long with steel peg and locking brackets.  The pegs stay shall have three holes to open the side hung casement in three different angles.  The peg stay shall be of minimum thickness 2 mm in case of brass or aluminium and 1.25 mm in the case of steel, where specified friction hinges shall be provided.  Side hung shutters fitted with friction hinges shall not be provided with a peg stay.

Fig. 4 Steel doors, windows and ventilators

If specified, side hung shutters may be fitted with an internal removable fly proof screen in a 1.25 mm thick sheet steel frame to the another frame of the shutter by brass turn buckles at the jambs, and brass studs at the sill to allow the screen being readily removed. The windows with removable fly proof screen shall be fitted with a through-the-screen level operator at the sill level to permit the operation of the shutter through an angle of 90 degree without having to remove the fly proof screen.  The level shall permit keeping the shutter open in minimum three different positions.

7.12.6. STEEL VENTILATORS

a) Top hung ventilators - The steel butt hinges for top hung ventilators shall be riveted to the fixed frame or welded to it at the back after cutting a slot in it.  Hinges to the opening frame shall be riveted or welded.

Top hung ventilators shall be provided with a peg stay with three holes which when closed shall be held tightly by the locking bracket.  The locking bracket shall either be fitted to the fixed frames or to the window.

b) Centre hung ventilators

Central hung ventilators shall be hung on two pairs of brass or aluminium cup pivots as specified, riveted to the inner and outer frames of ventilators to permit the ventilator shutter to swing to angle of approx. 85 degree.  The opening portion of the ventilators shall be so balanced that it remains open at any desired angle under normal weather conditions.

 A black oxidised steel spring catch approved by the engineer shall be fitted in the centre of the top of the centre hung ventilator, for the operation of ventilators.  The spring catch shall be secured to the frame with M. S. screws and shall close into a mild steel or malleable iron catch plate riveted, screwed or welded to the outside of the outer window frame bar.

A black oxidised cord pulley wheel in galvanised mild steel brackets shall be fitted at sill of the centre hung window with mild steel screws or alternatively welded together with a mild steel or malleable iron cord-eye riveted or welded  to the bottom inner frame bar of the window in a position corresponding for that of pulley.

Removable fly proof screen may be provided as specified.  This shall be fitted with a through–the-screen operator to enable operating and keeping the shutter open in minimum three different positions.

7.12.7. Composite units

Composite Units consist of combination of two or more units of doors, windows and ventilators etc. as the case may be.  The different units shall be coupled by using coupling sections. K11 B or K12 B as the case may be.

Wherever the ventilators, windows and doors shall be coupled with coupling sections, mastic cement shall be applied between the junctions to make the water tight.

7.12.8. Glazing

The glass panes shall have square corners and straight edges. The glass panes shall be so cut that it fits slightly loose in the frames. In doors, windows and clerestory windows of bath, WC and lavatories frosted glass panes shall be used which shall weigh not less than 10.00 kg/m2.

Glazing shall be provided on the outside of the frame unless otherwise specified.  Putty of approved make conforming to IS: 419 shall be used for fixing glass panes.  Putty shall be applied between glass panes and glazing bars.  Putty shall then be applied over the glass pane, which shall stop 2 to 3 mm from the sight line of the back rebate to enable the painting to be done up to the sight line to seal the edge of the putty to the glass.  The oozed out putty shall be cleaned and from putty cut to straight line.  Quality of putty shall not be less than 185 gm/metre of glass perimeter. Putty shall be painted within 2 to 3 weeks, after glazing is fixed to avoid its cracking.

Note: Putty may be prepared by mixing one part of white lead with three parts of finely powdered chalk and then adding boiled linseed oil to the mixture to from a stiff paste and adding varnish to the paste at the rate of 1 litre of varnish to the paste to 18 kg of paste.

Four glazing clips may be provided per glass pane for a size larger than 30 cm x 60 cm for all types, where the glass panes size exceed 80 cm x 200 cm, 6 glazing clips shall be used.  In case of doors, windows and ventilators without horizontal glazing bars, the glazing clips may be spaced according to the slots, in the vertical members provided the spacing does not exceed 30 cm otherwise the spacing shall be 30 cm.

Note: Where large size glass panes are required to be used or where the door or window is located in heavily exposed situation, holes for glazing clips have to be drilled prior to fabricating and cannot be done at any later stages. Use of glazing clips, shall be specified while placing the order.

Where specially stipulated, fixing of glass panes may be done with metal or wooden beading instead of mere putty.  Where beadings are proposed to be used, the manufacturers shall be intimated in advance to drill holes for hard screws.  Usually beads shall be fixed with screws spaced not more than 10 cm from each corner and the intermediate not more than 20 cm apart.  When glass panes are fixed with wooden or metal beading having mitred joints, a thin layer of putty shall be applied between glass panes and sash bars and also between glass panes and the beading.

 Where metal beading is specified extra payment shall be made on this account.

7.12.9. Finishing

All steel surfaces shall be thoroughly cleaned of rust, scale and dirt.  Where so specified, the steel surfaces shall be treated for rust proofing by the hot dip, zinc spray or electro galvanising process. A priming coat of approved steel primer i.e. red oxide zinc chrome primer conforming to IS: 2074 shall be given.  The fabricated steel door, windows, ventilators and composite units shall be inspected in the factory and approved by the engineer before priming coat is applied. Final finishing coat shall be given to the doors, windows and ventilators after they are erected and fixed in final position.  The rate shall be exclusive of final finishing coats but shall include the priming coat.

7.12.10. Fixing

Steel, doors and windows shall be so stacked as to keep them in true shape without damage.  Doors, windows and ventilators shall be fixed as described below

Opening may be flush or rebated as shown in the drawings.  Those opening may have rendered finish or a “fair faced” finish (i.e., without rendering as in case of marble or stone facing).  Where openings are flush and with a rendered finish a clearance of 1.25 cm shall be provided between the steel frame and opening (see Fig. 5).  In case of external masonry finish “fair faced” and with rebated jambs, a minimum 1.25 cm clearance between frame and opening shall be provided (see Fig. 5) opening in steel work shall be so designed that the outer flange of the door, windows, or ventilator frame section overlaps the steel surface by 10 mm (see Fig. 5.).

Note: The sizes of Indian Standard doors, windows and ventilators, are designed for modular opening 1.25 cm larger all round than the doors, windows, etc.  This gap of 1.25 cm is for the purpose of fixing of doors, windows etc.  In masonry openings, the gap is filled up with mastic cement and plaster after the door or windows are fixed in position.  In the case of steel or timber modular openings, extra steel or timber fillets will be necessary to cover this gap of 1.25 cm.

7.12.11. Fixing in masonry openings

a)  Fixing with lugs

  1. Doors, windows and ventilators unit, shall not be “built in” as the work proceeds but opening shall be left out and frames fitted afterwards so that the minimum specified clearance between opening and unit frame is left alround. The size of the opening shall first be checked and cleared of obstruction, if any.  The position of the unit and fixing holes shall be marked on the jamb.  Necessary holes shall be made in the masonry and lugs not less than 10 cm long 15 x 3 mm size fixed in cement concrete blocks 15 x 10 x 10 cm size of 1:3:6 (1 cement  3 coarse sand  6 graded stone aggregate 20 mm nominal size). The frames of units shall be set in the opening by using wooden wedges at the jamb, head and sill, (wedges shall preferably be placed near the points where a glazing bar meets the frames and be plumbed in position).
  2. After it, the frame shall be fixed with the lugs with 20 mm long and 6.3 mm dia. G. I. counter sunk machine screws and nuts.  In case of flush opening which are rendered smooth, wedges shall be removed and gap between unit and the jambs shall be filled with cement mortar (Fig. 5).
  3. In case of flush jamb with external “fair faced” finish the gap between the opening and frame shall be filled with mastic from inside till it oozes out on external face.  The oozing mastic shall be cleaned and flush pointed.  The internal gap shall be filled with mastic to about 1/3rd depth and the rest with cement mortar (Fig. 5).
  4. In case of rebated jambs finished “fair faced” externally, the mastic shall be freely applied to the inside channel of frame, jamb and sill, so as to ensure a water tight joint.  After the unit is firmly fixed in position surplus mastic shall be cleaned and flush pointed, as shown in (Fig. 5).

b)  Fixing with screws and plugs

In R. C. C. work where lugs cannot be embedded due to reinforcement bars etc. rawl plugs or other approved metallic fasteners may be fixed in proper position and frame fixed to them with 60 mm galvanised wood screws of designation 10.

c) Fixing in wood work opening

Opening in wood work are normally rebated and approved mastic or rubber linings shall be applied to jambs, sill and channel before fixing in position.  The frame shall be set in opening using wooden wedges as specified and fixed to the opening with 60 mm galvanised wood screws of designation 10. Extra timber fillets of hard wood to match the adjoining work shall also be provided around the frame to close the extra gap between openings and frame   (Fig. 5).

d) Fixing in steel work opening

Before placing the unit frame in position approved mastic shall be applied as specified and a mild steel or hard wood fillet shall be provided around the frame to close the extra gap between opening and frame.  The unit shall then be fixed to the opening with fixing clips or with nuts and bolts as shown in the drawings or as directed by the engineer (Fig. 5).

e) Fixing of composite units

The fixing procedure for composite units shall be generally be as described under ….to…except that:  

Where large units shall be formed by coupling individual units together (with coupling sections), the mullions and transom shall be bedded in mastic to ensure water tightness. Mastic shall be applied liberally to the channels of the outside frame sections before assembly and after coupling.  All oozing out mastic shall be cut out neatly.

7.12.12. Precautions

Care shall be taken that steel doors and windows etc. are not deformed/damaged during subsequent constructions. Particular care shall be taken that scaffolding do not rest on the steel door window frames or glazing bars.

All fittings and hinges (projecting hinges) shall be protected, preferably with alkathene sheets so that these may not be damaged during execution of work.

7.12.13. Measurement

The height and width shall be measured correct to 1 mm. The area shall be calculated in square meter correct to two places of decimal. The fixed side hung and top hung, categories shall be measured separately.

All composite units shall first be measured as fixed. Extra shall then be added for side hung, top hung and centre hung portions. The measurements for extra for side hung, centre hung and top hung windows shall be measured from outside to outside of the casement frames.

7.12.14. Rate

Rate shall include the cost of materials and labour involved in all the operations described above excluding two coats of painting but including cost of glazing and priming including the cost of projecting hinges in case of side hung doors/windows, plain hinges in case of top/bottom hung windows/ventilators and pivots for centre hung windows / ventilators.

Metal beading and other fittings such as peg stays and casement window fasteners etc. shall be enumerated and paid for separately. (Please refer additional specifications in Annexure 7-A.11).

7.13.1. SPECIFICATIONS FOR T-IRON DOORS, WINDOWS AND VENTILATORS FRAMES

T-iron doors, windows and ventilators frames shall be manufactured from uniform mild steel Tee section.  The steel shall be of the grade as provided in clause 7.1.10. The frames shall be got fabricated in workshop approved by the engineer.

The sizes of doors, windows and ventilator frames shall be as per drawing or as directed by the engineer MS tie bar of 10 mm dia shall be welded at bottom of the frame.  The size of doors, windows and ventilators shall be calculated so as to allow 12.5 mm clearance on all sides to allow an easy fitting in opening.  The actual size of doors, windows and ventilators shall not vary by more than ± 2 mm than those shown in the drawings.

The size of T Section used for manufacture of doors, windows and ventilators shall not be less than those specified in IS: 1038-1983 unless otherwise directed by the engineer. (See Fig. 6) 

7.13.2. Fabrications

The frame shall be constructed in section which has been cut to length and metered. The corners of the frames shall be butt welded to form a true and right angle.  All frames shall be square and flat meeting the requirements as stated under 7.12.3.1.

The T Section shall be mitre joined and continuously butt welded all along.  The requirement of welded joints shall be as specified under 7.12.4.

Fig. 5 T-Iron door, window frames

7.13.3. Fittings

Requisite number of holes shall be made in the frame for fixing of fitting.  Detailed arrangements of fixing fittings shall be as shown in (Fig. 6). All fitting shall be fillet welded to T iron frame all along the periphery of contact.

Butt hinges shall be fixed to the frame as below

i) MS flat of size 100 mm x 25 mm x 6 mm will be welded with fillet weld all along the periphery of contact on the rear side of the web of T-iron to receive the hinges.  Requisite number of holes shall be made in T iron frame and MS flat for fixing of hinges with counter sunk steel screws as shown in Fig. 6.

ii) An alternate method of fixing butt hinges can be adopted by fillet welding the hinge to the T iron frame on three sides. No welding shall be done along the hinge pin to allow free movement of butt hinges as shown in Fig. 6.

7.13.4. Fixing procedure

Fixing procedure for T iron doors, windows and ventilator frames in masonry opening shall be as described in clause 7.12.14.  Fixing arrangements of shutters to such frames is shown in Fig. 6.

7.13.5. Measurements

T-iron door, windows and ventilator frames shall be measured in running metre, along the centre line of the frame correct to a 1 mm and weight calculated on the basis of standard tables.  No deduction or extra payment shall be made for making holes and making arrangements for fixing fittings including packing wherever necessary.  No deduction will be made for not providing tie bars in case of windows and ventilators.

7.13.6. Rate

The rate includes cost of materials and labour involved in all the operations described above.  It shall include the necessary butt hinges and screws for fixing the same with frame or as specified.  But it does not include the cost of other door, window and ventilator fittings.

7.14. SPECIFICATIONS FOR PRESSED STEEL DOOR FRAMES (FIG. 7)

7.14.1. Material - Steel door frames shall be manufactured from commercial mild steel sheet of 1.25 mm thickness, conforming to IS:  2062-1999 and 4351-1976. Steel door frames with or without fan light shall be made in the profiles indicated in (Fig. 7) which may be manufactured to suit doors of either type opening inwards or outwards as directed by the engineer.

7.14.2. Construction - Each door frame shall consist of hinge jamb, lock jamb, head and if required angle threshold (See Fig. 7). These shall be welded or rigidly fixed together by mechanical means. Where no angle threshold is required, temporary base tie shall be screwed to the feet of frames in order to form a rigid unit.  Where so specified base ties shall be pressed mild steel 1.25 mm thick adjustable to suit floor thickness of 35 or 40 mm and removable, or alternatively, threshold of mild steel angle of section 50 x 25 mm, minimum shall be provided for external doors frames.

7.14.3. Fabrication - The pressed steel door frames shall be got fabricated in an approved workshop as approved by the engineer.

Fixing lugs (Fig. 7). There shall be three adjustable lugs with split end tail to each jamb without fan light, and four and jamb with fan light.

7.14.4.The head of the fixing lug shall be of one of the following lengths;

(a) 95 mm long for use with profile A (b) 120 mm long for use with profile B (c) 160 mm long for use with profile C. The head shall be made from flat steel strip 25 mm wide and not less than 1.60 mm thick.

7.14.5. The tail of the lugs shall be 200 mm long and shall be made of steel strip not less than 40 mm wide and not less than 1 mm thick.

7.14.6. Hinges (Fig. 7) 100 mm mild steel butt hinges shall be used. For door frames 89 cm wide and under, three hinges shall be rigidly fixed to one jamb and for frames and for door above 89.0 cm wide, four hinges shall be rigidly fixed to one jamb, if it is single shutter. Where the height of door shutter exceeds 2.15 metres, one additional hinge shall be provided for every 0.5 m or part thereof of the additional height.

7.14.7. In all cases the hinges shall be so fixed that the distance from the inside of the head to rebate to the top of the upper hinge is 20 cm and distance from top of upper range to the lower range is about 175 cm.

Fig. 6 Steel doors, windows & ventilators

7.14.8. Hinges shall be made of steel 2.5 mm thick with zinc coated removable pin of 6 mm, diameter.  The space between the two leaves of the hinge when closed shall be 3 mm and the leaf that is not welded to the frame shall have four counter sunk holes to take No.10 wood screws.

Fig. 7 Pressed steel doors and window frames

Fig. 6 (Contd.) Steel doors, windows & ventilators

7.14.4. Mortar guards - Mortar guards as instructed by engineer shall be provided.  These shall be welded to the frame at the head of the frame for double shutter doors to make provision for bolts.

7.14.5. Lock-strike plate - There shall be an adjustable lock-strike plate of steel complete with mortar guard to make provision for locks or latches complying with the relevant Indian Standards.  Lock-strike plates shall be of galvanised mild steel and fixed at 95 cm from the head of the frame.

7.14.6.  Shock absorbers -  For side hung door there shall not be less than three buffers or rubber or other suitable material inserted in holes in the rebate and one shall be located on the centre line of the lock strike plate and the other two at least 45 cm above and below the centre line of the lock strike plate. For double shutter doors, there shall be two buffers of rubber or similar suitable material inserted in holes in the rebate in the lock jamb only at the head and spaced 15 cm at the either side of the centre line of the door.

7.14.7. Finish - The surface of door frame shall be thoroughly cleaned, free of rust, mill-scale dirt, oil etc. either by mechanical means, for example, sand or shot blasting or by chemical means such as picking. After pretreatment of the surface one coat of approved primer, i.e. red oxide zinc chrome primer conforming to IS 2074 and two coats of paints as directed by the engineer shall be applied to the exposed surface.

7.14.8. Fixing - Frames shall be fixed up right in plumb. To avoid sag or bow in width during fixing or during construction phase, temporary struts across the width preventing sides bulging inwards may be provided. Wall shall be built solid on each side and grouted at each course to ensure solid contact with frame leaving no voids behind the frame.

Three lugs shall be provided on each jamb with spacing not more than 75 cm. The temporary struts should not be removed till the masonry behind the frame is set.  In case screwed base tie is provided, this should be left in position till the flooring is laid when it can be removed.

After pretreatment of the surface, one coat of steel primer and two coats, of paint, as directed by the engineer shall be applied to the exposed surface.

7.14.9. Measurements - The length shall be measured in running meter correct to a cm along the centre line of the frames.

7.14.10. Rate - The rate shall include the cost of labour and materials involved in all the operations described above including application of one coat of approved steel primer, i.e. red oxide zinc chrome primer conforming to IS: 2074.

7.15. SPECIFICATIONS FOR FAN CLAMPS (FIG. 8)

7.15.1. Types - The fan clamp shall be of the following types

(a) Fan clamp to be fixed during the laying of R. C. C. slab, shall be of type 1, as shown in (Fig. 8).  This shall be made of 16 mm M.S. bar bent to shape with its ends hooked. The overall height of the clamps shall be made to suit the depth of the slab. (b) Fan clamp for beams shall be of type II as shown (Fig. 8). It shall be similar to fan clamp, type I, except that its height shall be greater depending on the depth of the beam rib. (c) In case low ceiling heights, circular cast iron box for ceiling fan clamp shall be of type III and fixed during the laying of R. C. C. slab and shall be as shown in (Fig. 8).  The size of cast iron box shall be 140 mm internal dia with 73 mm height, the thickness of cast iron rim shall be 4.5 mm bottom and top lid shall be of 1.5 mm thick M. S. sheet, with its top surface hacked so as to ensure proper bonding with the concrete. The lids shall be screwed into the cast iron box by means of 3.3 mm dia round head screws one each at the corners. The box can be of M. S. sheet, the thickness of side walls can be reduced to 3 mm without effecting inner dia of the box. 

The fan clamp shall be made of 12 mm dia MS bar bent to shape with its ends bent as per drawing.

7.15.2. Fixing - Holes for inserting the fan clamps in the positions shown in the drawing or as instructed by the engineer shall be made in the shuttering after the latter has been fixed in position. After steel reinforcement is tied, fan clamps shall be fixed with their loops truly vertical and at the correct depth from the underside of the slab or beam. The hooked arms and the loop shall be tied to the reinforcement, either directly or through cut pieces of M. S. bars with annealed steel wire 1.6 mm or 1.00 mm thick.  The clamp shall neither be disturbed out of position during concreting nor shall they be bent out of shape when shuttering of slabs or beams is removed.

The exposed portion of loops of the clamp shall be given two or more coats of paint, including priming each of approved steel primer as ordered by the engineer. 

7.15.3. Measurements - Clamps of type I and III shall be counted in numbers. Fan clamps type II, shall be counted and paid for under fan clamps type 1, but they shall in addition be paid for their extra height as determined by the depth of the beam.

7.15.4. Rate - The rate per fan clamp shall include the cost of labour and materials involved in all the operations described above.  In the case of type I and III clamps, the rate shall apply irrespective of the thickness of the slabs.

Fig. 8 Fan Clamps

7.16. SPECIFICATIONS FOR MILD STEEL CLAMPS AND RINGS FOR CHICKS

7.16.1. M. S. Clamps - These shall be fabricated from M. S. flat iron 20 mm x 6 mm.  One end shall be bent at right angles for 25 cm length and other end shall be tapered to a point.  Total length of clamp shall not be less than 15 cm.

These shall be built into the wall masonry, while the work is in progress, so as to project 2.5 cm from the finished surface. These shall be fixed in cement mortar. All clamps shall be fixed in straight horizontal line as shown in drawings or as specified by the engineer.

7.16.2. M. S. Rings - These shall be made of 6 mm dia bars with 40 mm internal diameter. Their joint shall be well formed or welded together.  These shall be provided with a 50 mm forked clamp of 10 x 3 mm M. S. flat iron.  It shall be wide at the fork end and pointed on the other end.

These shall be fixed in the masonry as specified.

7.16.3. Measurements - The M. S. clamps and rings shall be counted in numbers.

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

7.17. SPECIFICATIONS FOR M. S. BARS AND M. S. GRILLS IN WOODEN OR STEEL FRAMES

7.17.1.  M. S. round or square bars, with or without  M. S. flats M. S. grills of different patterns with flats with M. S. or without M. S. bars, round or square, fixed in wooden or steel windows or clerestory windows etc. are described in this clause.

7.17.2. Fabrication

When M. S. bars round or square are to be fixed in wooden or steel frame these are cut in to required length to form the required pattern then fixed as per drawing.   In case of wooden frames the length will be for fixing in the hole 5 cm deep in one frame and right through and flush with outer side of the frame. When M. S. round or square bars are to be fixed to steel frames or in combination with M. S. flats these are to be cut to proper size welded to steel frames or MS flats to form the required pattern. In case of M. S. flats they should have counter sunk holes to facilitate fixing them to wooden frames with wood screws.  Welding to be done in an approved workshop and not at site.

When the grill is to be fabricated mainly with M. S. flats with or without M. S. round or square bars, the flats of required size are cut and bent to form the required pattern and length and design as per drawing or as directed by the engineer.  The cut and bent flats and bars are then welded by fillet welding all around the width of the flats or circumference of bars which are joined, forming at right angle corners of flat proper mitered joint angle shall be provided with welding for full width.  Welding to be done in approved workshop and not at site.

7.17.3. Fixing

When MS round or square bars are to be fixed to wooden frames the bars shall be passed in to the wooden frame, from the end having a through hole and fixed flush with that end while at the other end it will be 5 cm deep in the hole drilled in the frame.  In case of steel frames, the bars will be welded to the steel frame by fillet weld all along the circumference of the bars in an approved workshop and not at site. In case of grill of bars welded to M. S. Flat forming the required pattern, the outer frame of M. S. flats shall be fixed to the wooden frame with wood screws in the counter sunk holes drilled in M. S. flats ensuring that screws are driven with some screw driver (not hammered) till the screws are embedded fully inside flush with the M. S. flats. In case of fixing to steel frames, M. S. flats of required pattern with or without M. S. round or square bars, the method of fixing will be similar to what is described above. Any kind of welding at site shall be permitted only under written order of the engineer.

7.17.4. Measurements - The different types of M. S. grills as described will be measured separately and paid for.  The length of bars and flats used in grills will be measured correct to a cm and then weights calculated in kg by using standard tables.

7.17.5. Rate - The rate shall include the cost of materials and labour required for all the operations described above.  Grill of different types as mentioned shall be paid for separately.

7.18. Specifications FOR tubular trusses 

7.18.1. Structural steel tube - These shall be of - (1) Hot finished welded (HFW) type, or (2)Hot finished seamless (HFS) type, or (3) Electric resistance or induction butt welded (ERW), having carbon content less than 0.03 percent, yield stress of 21.5 kg/mm (YST 22) type, Conforming to the requirement of IS: 1161.  The steel tubes when analysed in accordance with the method specified in IS: 226 shall show not more than 0.06 percent Sulphur, and not more than 0.06 percent phosphorous.

Tubes shall be designated by their nominal bore.  These shall be light, medium or heavy as specified depending upon the wall thickness. The standard size and weights of tubes are listed in Annexure 7-A.12. Tubes shall be clean finished and reasonably free from scale.  They shall be free from cracks, surface flaws, laminations and other defects.  The ends shall be cut clean and square with axis of tube, unless otherwise specified.

7.18.2. Minimum thickness of metals - 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.

7.18.3. Fabrication

The component parts of the structure shall be assembled in such a manner that they are neither twisted nor otherwise damaged and be so prepared that the specified cambers, if any, are maintained.  The tubular steel work shall be painted with one coat of approved steel primer after fabrication.  All fabrication and welding is to be done in an approved workshop.

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

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

In all cases, where the full 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 nuts to be completely tightened.

Welding - Where welding is adopted, it shall be as per IS: 816.

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

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

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 sections shall be gradual.

Hoisting and erection - Tubular trusses shall be hoisted and erected in position carefully, without damage to themselves other structure, equipment and injury to workman.

The method of hoisting and erection proposed to be adopted shall be got approved from the engineer.  The contractor shall however be fully responsible, for the work being carried out in a safe and proper manner without unduly stressing the various members.  Proper equipment such as derricks, lifting tackles, winches, ropes etc. shall be used. 

7.18.4. Measurements - The work as fixed in place shall be measured in running metres correct to a centimetre and their weights calculated on the basis of standard tables correct to the nearest kilogram unless otherwise specified.

Weight of cleats, brackets, packing pieces bolts, nuts, washers distance pieces separators diaphragm gussets (taking overall square dimensions) fish plates, etc. shall be added to the weight of respective items unless otherwise specified.  No deduction shall be made for skew cuts.

7.18.5. Rate - The rate shall include the cost of labour and materials involved in all the operations described above include application of one coat of approved steel primer i.e. red oxide zinc chrome primer conforming to IS: 2074.

Annexure-7.A.1

List of Bureau of Indian Standards (IS) **

Sl.No

IS No.

Subject

1

63-1978

Whiting for paints and putty (2nd revision) (Amendment 2) (Reaffirmed 1994)

2

198-1978

Varnish gold size (1st revision) (Amendment 1) (Reaffirmed 1991)

3

226-1975

Structural steel (standard quality) (5th revision) superseded by IS 2062:1992.

4

277-2003

Specification for galvanized steel sheets (plain and corrugated) (5th revision) (Amendments 2)

5

800-1984

Code of practice for use of structural steel in general in steel construction (2nd revision) (Amendments 2) (Reaffirmed 1991)

6

806-1968

Code of practice for use of steel tubes in general building construction (1st revision) (Amendment 1) (Reaffirmed 1991)

7

812-1978

Glossary of terms relating to welding and cutting of metals (Reaffirmed 1991)

8

813-1986

Scheme of symbols for welding (revised) (Reaffirmed 1991)

9

814-2004

Covered electrodes for manual metal arc welding of carbon and carbon manganese steel (5th revision) 

10

815-1974

Classification and coding of covered electrodes for metal arc welding of structural steels (2nd revision) (Supercedes by IS 8141:1991).

11

816-1969

Code of practice for use of metal arc welding for general construction in mild steel (1st revision) (Amendments 2) (Reaffirmed 1992)

12

817-1966

Code of practice for training and testing of metal arc welders (revised) (Reaffirmed 1991) Part I-1992, Part-II-1996

13

818-1968

Code of practice for safety and healthy requirements in electric and gas welding and cutting operations (1st revision) (Reaffirmed 1991)

14

822-1970

Code of procedure for inspection of welds (Reaffirmed 1991)

15

823-1964

Code of procedure for manual for metal arc welding in mild steel (withdrawn)

16

1038-1983

Steel doors, windows and ventilators (3rd revision) (Amendment 1) (Reaffirmed 1991)

17

1081-1960

Code of practice for fixing and glazing of metal (steel and aluminium) doors, windows and ventilators (Amendment 1) (Reaffirmed 1991)

18

1148-1982

Hot rolled steel rivet bars (upto 40 mm diameters) for structural purposes (3rd revision) (Reaffirmed 1992)

19

1161-1979

Steel tubes for structural purposes (3rd revision) (Amendments 2) (Reaffirmed 1998)

20

1182-1983

Recommended practice for radiographic examination of fusion welded butt joints in steel plates (2nd revision) (Reaffirmed 1991)

21

1200-1993

(Part 8)

Method of measurements of building and civil engineering works

Part 8 steel work and iron works (4th revision) Part I,II & III 2002

22

1363-1992

Hexagonal head bolts, screws and nuts of product grade C 2002

 

Part-1

(Hexagon head bolt) (size range M5 to M64) (3rd revision) 2002

 

Part-2

(Hexagon head screws) (size M5 to M64) (3rd revision) 2002

 

Part-3

(Hexagon nuts) (size range M5 to M64) (3rd revision) 2002

23

1367-1980

(Part 1-19) Technical supply conditions for threaded steel fasteners (Part 1 to 19)

24

1599-1985

Method for bond test for steel products other than sheet, strip, wire and tube (2nd revision) (superseding IS 1692 : 1974, IS 3260 : 1960, 815, 4598 : 1968) (Reaffirmed 1991)

25

1608-2005

Method of tensile testing for steel products (1st revision) (Amendments 1) (Reaffirmed 1991)

26

1821-1987

Dimensions for clearance holes for bolts and screws (3rd revision) (Reaffirmed 1992)

27

1852-1985

Rolling and cutting tolerances for hot rolled steel products (4th revision) (Amendment 1) (Reaffirmed 1991)

28

1894-1972

Method for tensile testing of steel tubes (1st Revision) (Reaffirmed 1991)

29

1977-1975

Structural steel (ordinary quality) (2nd revision) (Amendments 4) (Reaffirmed 1996)

30

2062-1992

Steel for general structural purposes (4th revision) (Supersedes IS 226:1975) (Amendment 1) 1999

31

2074-1992

Ready mixed paint, air drying red oxide-zinc chrome, priming (2nd revision)

32

4351-1976

Specification for steel door frames (1st revision) (Amendment 1) (Reaffirmed 2003) 2003

33

4454-1981

(Part 1)

Steel wires for cold formed springs. Patented and cold drawn steel wires unalloyed (2nd revision) (Reaffirmed 1992) Part I -2001, Part II -2001, Part II – 1975 & Part IV 2001

34

4736-1986

Hot-dip zinc coatings on mild steel tubes (1st revision) (Amendment 1) (Reaffirmed 1992)

35

6248-1979

Metal rolling shutters and rolling grills (1st revision) (Reaffirmed 1991)

36

7452-1990

Specifications for hot rolled steel sections for doors, windows and ventilators (2nd revision).

Annexure 7-A.2

 SPECIFICATIONS FOR STEEL FOR GENERAL STRUCTURAL PURPOSES

(Extract of IS: 2062-1999)

1. Scope

1.1. This Indian Standard covers the requirements of steel plates, strips, sections, flats, bars, etc, for use in structural work.

1.1.1. The steels are suitable for welded, bolted and riveted structures, and for general engineering purposes.

1.2. Where welding is employed .for fabrication and guaranteed weld ability is required, welding procedure should be as specified in IS: 9595-1996 Metal arc welding of carbon and carbon manganese steels-Recommendations (first revision)

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

IS.No.               Title  
228 Methods of chemical analysis of steel  

1599-1955

Method for bend test (second revision)

1608-1995

Mechanical testing of metals Tensile testing (second revision)

1757- 1988

Method for Charpy impact test (V notch) for metallic material (second revision)

1852-1985

Rolling and culling tolerances for hot-rolled steel products (third revision)

1956

Glossary of terms relating to iron and steel

3803 (Part1) -1989

Steel - Conversion of elongation values: Part I Carbon and alloy steels (second revision)

8910-1978

General technical delivery requirements for steel and steel products

9595=1996

Metal arc welding of carbon and carbon manganese steels  Recommendations (first revision)

10842-1984

Testing and evaluation procedure for Y groove crackability test

3. Terminology - For the purpose of this standard, the following definitions in addition to those given in the relevant parts of IS: 1956 shall apply.

3.1. Micro-alloying elements - Elements, such as niobium, vanadium and titanium, added singly or in combination to obtain higher strength levels combined with better form ability, weldability and toughness as compared with non-alloyed steel produced to equivalent strength levels.

3.2. Weldability - A metallic substance is considered to be weldable by a given process and. for the given purpose, when metallic continuity to a stated degree can be obtained by welding using a suitable procedure, so that the joints comply with the requirements specified in regard to both their local properties and their influence on the construction of which they form a part.

4. Supply of material - General requirements relating to supply of weldable structural steel shall conform to IS 8910.

5. Grades - There shall be three grades of steel as given in Tables 1 and 3.

Grade- A steel specified in this standard is intended for use in structures subject to normal conditions for non-critical applications. The use of Grade A steel is generally justified for these structural parts which are not prone to brittle fracture on account of its thickness, size and shape adopted and/or because of the fabrication and / or service conditions.

Grade-B steel specified in this standard is intended for use in structures subject to critical loading applications, where service temperatures do not fall below 0°C. Use of Grade B steel is generally specified for those structural parts which are prone to brittle fracture and/or are subjected to severe fluctuation of stresses.

Grade-C steel specified hi this standard, is supplied with guaranteed low temperature impact properties. This grade is intended to be used in structures or structural parts, where the risk of brittle fracture requires consideration due to their design, size and/or service conditions. In cases where owing to increased thicknesses, loading conditions and general design of the structures, higher resistance to brittle fracture is required, use of steel of Grade C with a guarantee of impact properties at 00C or -20°C or -40°C will be advisable.

The steel products conforming to the requirements of this specification can be rolled from the cast billet ingots, billets, blooms, slabs and continuously cast billets, blooms or slabs conforming to IS: 2830:1992 Carbon steel cast billet ingots, billets, blooms and slabs for re-rolling into steel for general structural purposes (second revision).

6. Manufacture - The processes used in making the steel and manufacturing hot rolled steel plates, strips, sections, flats, bars, etc, are left to the discretion of the manufacturer. If required, secondary refining may follow steel mating.7. Freedom from defects

7.1. All finished steel shall be well and cleanly rolled to the dimensions, sections and masses specified. The finished material shall be reasonably free from surface flaws; laminations; rough/jagged and imperfect edges: and alt other harmful defects.

7.2. Minor surface defects may be removed by the manufacturer by grinding provided the thickness is not reduced locally by more than 4 percent below the minimum specified thickness. Reduction in thickness by grinding greater than 4 percent, but not exceeding 7 percent, may be made subject to mutual agreement between the purchaser and the manufacturer.

7.2.1. Subject to agreement with the purchaser. Surface defects which cannot be dealt with as in 7.2 may be repaired by chipping or grinding followed by welding and inspection by a mutually agreed procedure such that: (a) after complete removal of the defects and before welding, the thickness of the item is in no place reduced by more than 20 percent; (b) welding is carried out by approved procedure by competent operators with  approved electrodes and that the welding is ground smooth to the correct nominal thickness; and( c) subsequent to the Finish grinding, the item may be required to be normalized or otherwise heat-treated at the purchaser's direction.

7.3. However, welding as mentioned in 7.2.1 is not permissible for Grade C material.

7.4. The material may be subjected to non-destructive testing to determine soundness of internal subject to mutual agreement between the purchaser and the manufacturer.

8. Chemical compositions

8.1. The ladle analysis of the steel, when carried out by the method specified in the relevant parts of IS 228 or any other established instrumental / chemical method, shall be as given in Table I. In case of dispute. The procedure given in IS:  228 and its relevant parts shall be the referee method. 

However, where the method is not given in IS: 228 and its relevant parts, the referee method shall be as agreed to between the purchaser and the manufacturer.

8.2. Product analysis - The product analysis shall be carried out on the finished product from the standard position.

Permissible limits of variation in case of product analysis from the limits specified in Table 1 shall be as given in Table 2.

Table 1 Chemical composition   (Clause 5.8.1and 8.2)

Grade composition

Ladle Analysis, Percent, Max

Carbon equivalent

Deoxida-tion Mode

Supply condition

C

Mn

S

P

Si

(CE) Max

A

Fe

410 WA

0.23

1.50

0.050

0.050

0.40

0.42

Semi-killed or killed

As rolled 

B

Fe

410 WB

0.22

1.50

0.045

0.045

0.40

0.41

Killed

As rolled Plates above 12 mm may be normalized / controlled cooled if agreed to between the purchaser and the manufacturer

C

Fe

410 WC

0.20

1.50

0.040

0.040

0.40

0.39

Killed

As rolled Plates above 12 mm shall be normalized / controlled cooled

Notes:

                                                            Mn       Cr + Mo + V         Ni + Cu

1. CE based on ladle analysis = C + ------- +  -----------------  +  ------------

                                                             6                  5                     15

2. When the steel is killed by alluminium alone, the total aluminium content shall not be less than 0.02 percent.  When the steel is killed by silicon alone, the silicon content shall not be less than 0.10 percent.  When the steel is silicon-aluminium killed, the silicon content shall not be less than 0.03 percent and total aluminium content shall not be less than 0.01 percent.

3. When micro-alloying elements like Nb, V and Ti are used individually or in combination, the total content shall not exceed 0.20 percent.

4. if mutually agreed to between the purchaser and the manufacturer, the steel may be supplied in the copper bearing quality in which case the copper shall be present between 0.20 to 0.35 percent on ladle analysis.  In case of product analysis, the copper content shall be between 0.17 and 0.38 percent.  The copper bearing quality steel shall be designated with a suffix Cu, for example Fe 410 Cu-WA.

5. Nitorgen content of the steel should not exceed 0.012 percent, which shall be ensured by the manufacturer by occasional check analysis.

6. Details of elements other than those specified may be specified if agreed at the time of inquiry and order

Table 2 Permissible variations for product analysis (Clauses 5 and 8.2)

Constituent

Permissible variations over the specified limit, percent, max

Carbon

0.02

Manganese

0.05

Silicon

0.03

Sulphur

0.005

Phosphorus

0.005

9. Selection and preparation of test samples

9.1. The position from which test samples are taken shall be so located in the product as to yield the clearest possible information regarding properties in the cross-sectional and longitudinal planes. The recommended locations for taking less samples for plates, sections and bars are indicated in Fig.1. Alternatively, in case of sections, the samples may be taken from the web.

9.2. Wherever practicable, the rolled surface of the steel shall be retained on the two opposite sides of the test samples.

9.3. In case of flat test samples for tensile test, both surfaces are normally to be left on the test samples for strips and plates up to 32 mm thick. At least one rolled surface shall be left on rectangular test samples taken from plates exceeding 32mm in thickness. Round test samples are permitted, but should only be adopted for thickness exceeding 28 mm.

9.4. In case of flats up to 16mm thick, the test sample shall undergo, if possible, no machining whatever, prior to use as a test piece. If this is not possible, the test sample shall undergo the minimum amount of machining.

9.5. Bars below 28 mm shall be tested without machining.  In case of bars having diameters or thickness between 28 mm and 71 mm. the bars may, be symmetrically reduced by machining.  For bars having diameters or thicknesses exceeding 71 mm. The test sample may be taken from the position shown in Fig. 1.

9.6. In case of plates, strips, sections and flats, bend tests shall be carried out on rectangular test samples which, as far as possible, should be of the full thickness of the product. In case of plates, sections and flats exceeding 28 mm in thickness, it is permissible to remove metal from one side of the test sample before using it as a test piece. The rolled surface of the test piece shall be on the outer side of the bend during the test.

9.7. Before-test samples are detached, full particulars regarding cast number, size and mass of

plates, strips, sections, flats and bars in each cast shall be furnished by the manufacturer to the purchaser. In case of plates, the number of plates in each cast shall also be given.

9.8. Test samples shall be cut in such a manner that the deformation is avoided as far as possible. It shearing or flame-cutting is employed; an adequate allowance shall be left for removal by machining.

9.9. Test samples shall not be subjected to heat treatment unless the material from which they are cut is similarly treated, in which case the test samples shall be similarly and simultaneously treated with the material before testing. Any slight straightening of test samples which may be required shall be done cold.

10. Tensile-test

10.1. Number of tensile tests

10.1.1. Plates, Strips, Sections (Angles, Tees, Beams, beams, Channels, etc and Flats) - One tensile test shall be made from finished steel for every 50 tonnes or part thereof rolled continuously from each cast, a separate test being made for each class of steel product (namely, plates, strips, sections and flats) rolled from a cast.

10.1.1.1. Where plates, strips, sections or flats of more than one thickness are rolled from the same cast, one additional tensile test shall be made from the material in each class of product for each variations in thickness of 6 mm.

10.1.2. Bars (Round, Square and Hexagonal) - One tensile test shall be made from finished product for each 50 tonnes or part thereof. If more than one diameter or thickness of the bar is processed, one or additional tensile test shall be made for each variation of 3 mm above or below the diameter or thickness of the bar ordered.

10.2. Tensile test pieces - The tensile strength, yield strength and percentage elongation of steel shall be determined from standard test pieces cut crosswise from plates and strips and lengthwise from sections, flats and bars. The test shall be carried out on the standard test pieces prepared in accordance with IS 1608.

10.2.1. As a rule, test pieces with a non-proportional gauge length complying with the requirements to Lo = 5.65 ÖS0 should be used for the tensile test, where Lo is the gauge length and SO is the cross sectional area of the test piece.

10.2.1.1. Test pieces with a non-proportional gauge lengths, other than 5.65 ÖS, may also be used in which case the elongation values shall be converted 5.65 ÖS0 in accordance with IS: 3503 (Part 1).

10.3. Tensile test - Tensile strength, yield strength and percentage elongation when determined in accordance with IS: 1608 shall be as given in Table 3.

10.1.1. In case of sections the thick ness of which is not uniform throughout the profile, the limits of sizes given in Table 3 shall be applied according to the actual maximum thickness of the piece adopted for testing.

10.3.2. Should a tensile test piece break-outside the middle half of the gauge length (see IS: 1608) and the percentage elongation obtained is less than the specified, the test may be discarded at manufacturer’s option and another test made from the sample plate, strip, section, flat or bar.

11. Bend test

11.1. Number of bend tests

Bend test shall be made from finished steel from each cast. The number of tests for every 50 tonnes material or part thereof, rolled continuously, shall as even below. One additional test shall be made 1 to each class of product and for each variation of thickness.

11.2. Bend test piece - The test pieces shall be cut crosswise from plates and strips and length wise from sections, flats and bars.  When section permits, these shall be not less than

40 mm wide. If the manufacturer so desires, round, square, hexagonal and flat bars and structural sections shall be bent in the full section as rolled.

11.2.1. In all bend test pieces, the rough edge or arris resulting from shearing may be removed by filing or grinding or machining but the test pieces shall receive no other preparation.

11.3. Bend test - Bend test shall be conducted in accordance with IS: 1599.

Table 3 Mechanical properties    (Clauses 5, 10.3, 10.3.1, 11.3.1, 12.1.1, 12.2 and 12.4)

Grade

Designation

Tensile strength Min, Mpa

Yield stress, Min, MPa

Percent elongation at gauge length 5.60ÖS0

Internal diameter of bend

Charpy V-notch impact energy J, Min

<20 

mm

20-40

mm

>40

mm

Min

Min

A

Fe 410 WA

410

250

240

230

23

3t

-

B

Fe 410 WB

410

250

240

230

23

2t for less than or equal to 25 mm thick products 3t for more than 25 mm thick products

27 (see Note 1)

C

Fe 410 WC

410

250

240

230

23

2t

27

Notes

1. For Grade B material, the minimum Charpy V-notch impact energy is to be guaranteed at 00C, if agreed to between the manufacturer and the purchaser.

2. For Grade C materials, the minimum Charpy V-notch impact energy shall be guaranteed at any one of the three temperatures, namely 00C, or –200C or –400C, as specified by the purchaser.

3. ‘t’ is the thickness of the material.

4. The impact values are given for a standard test piece.  When tested with subsidiary test pieces, the values shall not be less than the following:

Test piece size                            Charpy V-notch Impact Energy

     Mm                                                             J, Min

   10 x 7.5                                                         22

   10 x 5                                                           19.5

11.3.1. For bend test, the test piece at room temperature shall withstand bending through 180° to an internal diameter not greater than that given in Table 3 without cracking.

12. Impact test

12.1. Impact test shall normally be carried out on products having thickness/diameter greater than or equal to 12 mm.  The test specimen shall be so machined that the axis of the test specimen is parallel to the direction of rolling and the base closer to the rolled surface is more than 1mm from it. The notch axis shall be perpendicular to the rolled surface.

12.1.1. If stated in the order, impact tests may be carried out on products having a thickness less than 12 mm the dimensions of the test pieces shall be in conformity with IS 1757 (see also Note 4 of Table 3).

12.2. This lest is carried out using a V-notch lest piece (see IS 1757) the value for consideration being the arithmetic mean of the results obtained on three test pieces taken side by side from the same product (see Table 3).

12.3. The test sample shall be taken from the thickest product.  If the test sample taken from the thickest product rolled from a cast meets the requirements, the whole cast shall be seemed to meet the requirements of the test. If not, the test shall be performed on a section of next lower thickness rolled from the same cast and if it meets the requirements specified. This particular thickness as also other sections of lower thickness shall be deemed to satisfy the specification. If this thickness also does not meet the requirements. The test shall be carried out on the next lower thickness and so on, because the toughness of the product will be dependent on the rolling direction as well as on the section size.

12.3.1. A test sample shall be taken from each 50 tonnes or part thereof from the same cast.

12.4. The material represented shall be deemed to comply with the standard, if the average value of 3 test specimens, meets the requirements given in Table 3 provided no individual value shall be less than 70 percent of the specified value. If the average value of the three charpy impact tests fails to comply by an amount not exceeding 15 percent of the specified minimum average value, three additional test pieces from the same sample shall be tested and the results added to those previously obtained and a new average calculated. Provided this new average complies with the specified requirement, the material represented shall be deemed to comply with this standard.

13. Y Groove crackability test - Y groove crackability tests may be earned out in accordance with IS: 10842 for products of only Grade C material having thickness above 12 mm, if specifically agreed to between the manufacturer and the purchaser.

NOTE: The V groove crackability test will not be applicable for rounds and it is mainly for plates and sections.

14. Dimensions - Unless otherwise agreed to between the purchaser and the manufacturer the nominal dimensions of rolled products conforming to this standard shall be in accordance with the relevant Indian Standard. The Currently available Indian Standards are listed in Table 4.

15. Tolerances

The rolling and culling tolerances for steel product 2 conforming to this standard shall be those specified in IS: 1852. Stricter tolerances may be followed if agreed to between the purchaser and the manufacturer.

16. Retest - Should any one of test pieces first selected fail to pass (see any of the tests specified in this standard, two further samples shall be selected for testing in respect of each failure. Should the test pieces from both these additional samples pass, the material represented by the test samples shall be deemed to comply wish the requirements of that particular test.  Should the test pieces from either of these additional samples fail, the material represented by the test samples shall be considered as not having complied with this standard.

Table - 4 Indian Standards which give nominal dimensions of rolled steel products (Clause 14)

Product

Relevant Indian Standard

Beam, column, channel and angle sections

IS:808-1899 dimensions for hot rolled steel beam, column, channel and angle sections (third revision)

Tee-bars

IS: 1173-1978 Hot rolled slit steel tee bars (second revision)

Bulb angles

IS: 1252 – 1991 Hot rolled steel bulb angles – Dimensions (first revision)

Plates, strips and flats

IS:1730 – 1989 Steel plates sheets, strips and flats for structural and general engineering purposes (second revision)

Round and square bars

IS:1732-1989 Dimensions for round and square steel bars for structural and general engineering purposes (first revision)

Bulb flats

IS:1863-1979 Hot rolled steel bulb flats (first revision)

Sheet piling sections

IS:2314-1986 Steel sheet piling sections (first revision)

Channel sections

IS: 3954-1991 Hot rolled steel channel sections for general engineering purposes (first revision)

Track shoe sections

IS:10182 (Part 1)-1982 Dimensions and tolerances for hot rolled track shoe sections: Part 1 Section TS-L1

IS:10182 (Part 2)-1985 Dimensions and tolerances for hot rolled track shoe sections :Part 2 Section TS-H1

17. Calculation of mass - The mass of steel shall be calculated on the basis that steels weighs 7.85 g/cm3

18. Delivery - Subject to prior agreement between the purchaser and the manufacturer, suitable protective treatment may be given to the material after rolling.

19. Marking

19.1. Each product, with the exception of round, square and hexagonal ban and flats, shall carry or be marked with the manufacturer's name or trade-mark. Bars and flats shall carry a tag bearing manufacturer's name or trade-mark, Designation of steel should also be similarly marked on the product or tag,

19.2. Every heavy and medium structural mill product and each plate of thickness 10 mm and over shall be marked with the cast number.  In case of plates 10 mm thickness, the top plate of each pile (which consist of approximately 16 plates) shall be marked with the cast number and the remaining plates have suitable identification marking.

19.3. The ends of the rolled product shall be painted with a colour code as given below:

Grade A

Green

Grade B

Grey

Grade C

Orange

19.3.1. For the copper bearing quality, in addition the colour code as specified in 19.3, a white colour band shall be painted.

19.4. BIS certification marking - The material may also be marked with standard mark.

19.4.1. The use of the Standard Mark is governed by the provisions of Bureau of Indian Standard Act 1986 and the Rules and Regulations made there under. The details of conditions under which the license for the use of Standard Mark may be granted to manufacturers or producers may be obtained from the of Bureau of Indian Standard

Annexure 7–A.3

SPECIFICATIONS FOR MILD STEEL AND MEDIUM TENSILE STEEL BARS AND HARD – DRAWN STEEL WIRE FOR CONCRETE REINFORCEMENT  (PART I)  MILD STEEL AND MEDIUM TENSILE STEEL BARS (Third Revision) IS: 432(Part I)-1982

1.  Scope – Requirements of mild steel and medium tensile steel plain bars in round and square sections for use as reinforcement in concrete.

2. Types and grades   

a)  Mild steel bars; Grade I and Grade II, and

b)  Medium tensile steel bars.

Note: Grade II bars are not recommended for use in structures located in earthquake zones subjected to severe damage and for structures subjected to dynamic loading (other than wind loading).

3. Freedom from defects – Finished bars shall be sound and free from cracks, surface flaws, laminations and rough, jagged and imperfect edges, etc.

4. Nominal sizes – Diameter of round bars or side of square bars shall be 5, 6, 8, 10, 12, 16, 20, 22, 25, 28, 32, 36, 40, 45 and 50 mm.

5.  Tolerances

5.1. Bars in straight length

5.1.1. Size

Size

 

Tolerance (mm)

Over (mm)

Up to and Including ( mm)

-

25

35

50

80

100

25

35

50

80

100

-

±0.5

±0.6

±0.8

±1.0

±1.3

±1.6  percent  or

dia or side width

5.1.2. Ovality and out-of-square – Permissible ovality for round bars and out-of-square of square bars shall be 75 percent of total tolerance (plus and minus) specified on size.

5.1.3. Weight

Size

 

Tolerance, percent

Over (mm)

Up to and Including (mm)

 

-

10

16

 

 

10

16

-

 

±7

±5

±3

5.2. Coiled rounds and squares

5.2.1. Size -  ± 0.5 mm for size up to and including 12 mm.

5.2.2. Out of shape – Permissible value at any cross section shall not exceed 0.65 mm.

Note: 1) Size shall be diameter in case of round bars and side width in case of square bars.

Note: 2) No weight tolerance shall be applicable in case of coiled round and square bars.

6. Physical requirements

6.1. Ultimate tensile stress, yield stress and percentage elongation shall be as given in Table 1.

(see Next Page)

6.2. Bend test – Shall withstand the specified test.

Note: 1) For test procedures, refer to IS: 1608-1972 Method for tensile testing of steel products (first revision), IS : 1599-1974 Method for bend test for steel products other than sheet, strip, wire and tube ( first revision) both read in conjunction with IS: 226-1975  Specification for structural steel ( standard quality) ( fifth revision) and 9 of the standard.

Note: 2) For chemical composition refers to see 4 of the standard.

For detailed information, refer to IS: 432(Part I)-1982 Specification for mild steel and medium tensile steel bars and hard-drawn steel wire for concrete reinforcement: Part I Mild steel and medium tensile steel bars (third revision).

Table 1 Mechanical properties of bars

 

Sl.no

 

Type and nominal size of bar

 

Ultimate tensile stress

Min

 

Yield stress

Min

 

Elongation percent

Min

i

Mild Steel Grade I

For bars up to and including 20 mm

For bars over 20 mm, up to and including 50 mm

 

410

410

 

250

240

 

23

23

ii

Mild Steel Grade II

For bars up to and including 20 mm

For bars over 20 mm, up to and including 50 mm

 

370

370

 

225

215

 

23

23

iii

Medium Tensile Steel

For bars upto and including 16 mm

For bars over 16 mm, upto and including 32 mm

For bars over 32 mm, upto and including 50 mm

 

540

540

510

 

350

340

330

 

20

20

20

* Elongation on a gauge length 5.65 ÖSo where So is the cross-sectional area of the test piece.

Annexure 7-A.4

SPECIFICATIONS FOR HIGH STRENGTH DEFORMED STEEL BARS AND WIRES FOR CONCRETE REINFORCEMENT (Extract of IS: 1786-1985)

Deformed bars for concrete reinforcement are being produced in the country for many years, the main processes being hot rolling or hot rolling followed by cold twisting.  In the past decade there has been an increasing demand for higher strength deformed bars (415 N/m2, Min, yield strcngth/0.2 percent proof stress being the most common).  This high yield strength was being first achieved by raising carbon and manganese and to a great extent by cold twisting.

Micro-alloying with Nb, V, Ti and B, in combination. Individually, and thermo-mechanical treatment process are worth mentioning in tills field.  With these two processes higher strength values could be achieved at low carbon levels even in large diameter bars.

1. Scope

1.1. This annexure covers the requirements of deformed steel bars and wires for use as reinforcement in concrete, in the following three strength grades:

(a) Fe 415, (b) Fe 500, and  (c) Fe 550

Note: The figures following the symbol Fe indicates the specified minimum 0.2 percent proof stress or yield stress in N/mm2.

2. Glossary of terms

2.1. Batch – Any quantity of bars / wires of same size and grade whether in coils or bundles presented for examination and test at one time.

2.2. Bundle – Two or more coils or a number of lengths properly bound together.

2.3. Elongation - The increase in length of a tensile test piece under stress.   The elongation at fracture is conventionally expressed as a percentage of the original gauge length of a standard test piece.

2.4. Longitudinal rib – A rib of uniform cross-section, parallel to the axis of the bar/wire (before cold working, if any).

2.5. Nominal diameter or size - The diameter of a plain round bar/wire having the same mass per metre length as the deformed bar / wire.

2.6. Nominal perimeter of a deformed bar/wire – 3.14 times the nominal diameter.

2.7. Nominal mass – The mass of the bar / wire of nominal diameter and of density 0.007 kg/mm2 per metre run.

2.8. 0.2 Percent proof stresses – The stress at which a non-proportional elongation equal to 0.2 percent of the original gauge length takes place.

2.9. Tensile strength – The maximum load reached in a tensile test divided by the effective cross sectional area of the gauge length portion of the test piece, also termed as ultimate tensile stress.

2.10. Transverse rib - Any rib on the surface of a bar wire other than a longitudinal rib.

2.11. Yield stress - Stress (that is, load per unit cross-sectional area) at which elongation first occurs in (lie test piece without increasing the load during tensile test.  In the case of steels with no such definite yield point, proof stress shall be applicable.

3. Manufacture and chemical composition

3.1. Steel shall be manufactured by the open hearth, electric, duplex, basic oxygen, or a combination of these processes.  In case the manufacturer employs any other process, prior approval of the purchaser should be obtained.

3.1.1. Steel shall be supplied semi-killed or killed.

3.1.2. The bars/wires shall be manufactured from properly identified heats of mould cast, continuously cast steel or rolled semis.

3.1.3. The steel bars/wires for concrete reinforcement shall be manufactured by the process of hot-rolling.  It may be followed by a suitable method of cooling and/or cold working.

3.2. Chemical composition - The ladle analysis of steel when made as per relevant parts of IS: 228 shall be as follows:

Constituent

Percent, maximum

Fe 415

Fe 500

Fe 550

Carbon

0.30

0.30

0.30

Sulphur

0.060

0.055

0.055

Phosphorus

0.060

0.055

0.050

Sulphur and phosphorus

0.11

0.105

0.10

Note: 1) For guaranteed weldability, the percentage or carbon shall be restricted to 0 -25 percent, maximum.

Note: 2) Addition of micro alloying elements is not mandatory for any of the above grades.  When strengthening elements like Nb, V, B and Ti are used individually or in combination, the total contents shall not exceed 0-30 percent; in such case manufacturer shall supply the purchaser or his authorized representative a certificate slating that the total contents of the strengthening elements in the steel do not exceed the specified limit.

3.2.1. In case of product analysis, the permissible variation from the limits specified under 3.2 shall be as follows:

Constituent

Variation, over specified maximum limit, percent, max

Carbon

0.02

Sulphur

0.005

Phosphorus

0.005

Sulphur and phosphorus

0.010

3.2.2. For welding of cold-worked deformed bars, the recommendations of IS: 9417-1979 shall be followed.

3.2.3. In case of deviations from the specified maximum, two additional test samples shall be taken from the same batch and subjected to the test or tests in which the original sample failed.  Should both additional test samples pass the test, the batch from which they were taken shall be deemed to comply with this standard.  Should either of them fail, the batch shall be deemed not to comply with this standard.

3.3. Rolling and cold-working of bars/wires

3.3.1. All bars/wires shall be well and cleanly rolled and shall be round and free from surface defects and pipe, or oilier defects detrimental to its subsequent processing and to its end use.  Rust, seams, surface irregularities or mill scale shall not be the cause for rejection provider hard wire brushed test specimen fulfils all the requirements of this specification.

3.3.2. Stretching may or may not be combined with cold working.  The unworked length at each end of the bar/wire shall not exceed 100 mm or 4 times the nominal diameter, whichever is greater.

4.  Requirements for bond

4.1. High strength deformed bars/wires shall satisfy the requirements given in either 4.2 or 4.7.

4.2. Deformation and surface characteristics - For high strength deformed bars/wires, the mean area of ribs ( in mm2 ) per unit length (in mm) above the core of the bar/wire, projected  on a plane normal to the axis of the bar/wire calculated in accordance with 4.4 shall not be less than the following values:0.12 f  for £ 10 mm,  0.15 f for 10 mm < f  £ 16 mm, 0.17 f for f > 16 mm, where f is the nominal diameter of bar/wire in mm.

The mean projected area of transverse ribs alone shall be not less than one-third of the values given above.

4.3. The ribs contributing to the projected area considered in 4.2 shall consist of:

a) Longitudinal ribs in the form of continuous or discontinuous helix; and

b) Transverse ribs which after hot-rolling or cold-working are uniform in size and shape along the length of the hardwire, and are spaced along the bar/wire at substantially uniform distances.

4.4. The mean projected rib area per unit length Ar ( in mm2 per mm ) may be calculated from the following formula :  Where

ntr   =  number of rows of transverse ribs ;

Atr  = area of longitudinal section of a transverse rib on its own axis (see Fig.1) in mm

O  = including of the transverse rib to the bar axis (after twisting for cold - worked twisted bars) in degrees. Average value of two ribs from each row of transverse Fibs shall be taken;

str  =  spacing of transverse ribs in mm ;

mr =  number of longitudinal ribs;

d1r =  height of longitudinal ribs in mm ;

      =  nominal diameter of the bar / wire in mm ; and

sp  =  pitch of the twist in mm.                             

Note: 1. In the case of hot rolled bars / wires which are not subjected to cold twisting, the value of sp in the second term of the expression for Ar shall be taken as infinity rendering the value of the second term to zero.

Note: 2. Atr may be calculated as 2/3 ltr dtr where ltr and dtr are shown in Fig.1

Note3.  In the case of cold – worked bars / wires with some discontinuous longitudinal ribs, the number of longitudinal ribs, n1r shall be calculated as an equivalent number using the following formula and accounted for in the expression for Ar :

Where

mr’  =  number of discontinuous longitudinal ribs,

l’     =  average length of discontinuous longitudinal ribs

dtr’  =  height of discontinuous longitudinal ribs

str ‘  = averaged spacing of discontinuous longitudinal ribs, and

dtr   =  height of continuous longitudinal ribs.

Note: 4. The average length of discontinuous longitudinal ribs shall be determined by dividing a measured length of the bar equal to at least 10 f  by the number of discontinuous longitudinal ribs in the measured length, f being the nominal diameter of the bar.  The measured length of the bar shall be the distance from the center of one rib the center of another rib.

4.5. The heights of longitudinal land transverse ribs shall be obtained in the following manner

a) The average height of longitudinal ribs shall ribs shall be obtained from measurements made at not less than 4 points, equally spaced,  over a length of 10f or pitch of rib, whichever is greater.

b) The height of transverse ribs shall be measured at the centre of 10 successive transverse ribs.

4.6.  The average spacing of transverse ribs shall be determined by dividing a measured length of the bar / wire equal to at least 10f by the number of spaces between ribs in the measured length, f being the nominal diameter of the bar / wire.  The measured length of the bar / wire shall be the distance from the centre of one rib to the centre of another rib.

4.7. When subjected to pull-out test the bond strength calculated from the load at a measured slip of 0.025 mm and 0.25mm for deformed bars / wires shall exceed that of a plain round bar of the same nominal size by 40 percent and 80 percent respectively. 

4.7.1. The pull-out test shall be conducted in accordance with IS: 2770 (part 1)-1967* unless otherwise modified.

4.7.2. Bonded length of the bar embedded in the concrete shall be 5 times the diameter of the bar; the rest of the embedded length shall be made unbounded by providing plastic sleeve for that portion.

5.  Nominal sizes

5.1. The nominal sizes of bars / wires shall be as follows :

Nominal size, 4,5,6,7,8,10,12,16,18,20,22,25,28,32,36,40,45 and 50mm.

Note: Other sizes may also be supplied by mutual agreement.

5.2. The exact values for the cross- sectional area and nominal mass4es or individual bars / wires, shall be as given in Table 1.

5.3. Effective cross – sectional area of deformed bars and wires

5.3.1.  For bars / wires whose pattern of deformation is such that by visual inspection, the cross-sectional area is substantially uniform along the length of the bar / wire, the effective cross-sectional area shall be the gross sectional area determined as follows, using a bar / wire not less than 0.5 m in length :

Gross cross sectional area in mm2 =

Where

W = mass in kg weighed to a precision of ± 0.5 percent, and

L = length in m measured to a precision of ± 0.5 percent.

5.3.2.  For a bar / wire whose cross – sectional area varies along its length, a sample not less than 0.5 in long shall be weighed (w) and measured to a precision of ±  0.5 percent in the as rolled and / or

Fig. 1 Determination of longitudinal sectional area Atr of A transverse R1B

cold – worked condition, and after the transverse ribs have been removed, it shall be re-weighed (w’). The effective cross-sectional area shall then be round as follows:

Table d1 cross sectional area and mass ( clause 5.2 )

Nominal sized

Cross sectional area

Mass per meter

Mm

Mm2

kg

1

2

3

4

12.6

0.099

5

19.6

0.154

6

28.3

0.222

7

38.5

0.302

8

50.3

0.395

10

78.6

0.617

12

113.1

0.888

16

201.2

1.58

18

254.6

2.00

20

314.3

2.47

22

380.3

2.98

25

491.1

3.85

28

616.0

4.83

32

804.6

6.31

36

1018.3

7.99

40

1257.2

9.85

45

1591.1

12.50

50

1964.3

15.42

a)  Where the difference between the two masses ( w – w ’ )  is less than 3 percent of w’ , the effective cross-sectional area shall be obtained as in 5.3.1., b)  Where the difference is equal to or greater than 3 percent, the effective cross-sectional area in mm2 shall be taken as:

Where

W ‘ =  mass in kg of the bar with transverse ribs removed, and   L  =   length in m.

For routine test purposes, a nominal ratio of effective to gross cross-sectional area of bars / wires covered by (b) shall be declared and used by the manufacturer.

6.  Tolerances on dimensions and nominal mass

6.1.  Specified lengths -  If bars / wires are specified to be cut to certain l4engths, each bar / wire shall be cut within deviations of ± 75 25 mm on the specified length, but if minimum lengths are specified, the deviations shall be + 50mm and – 0 mm.

6.2. Nominal mass

6.2.1. For the purpose of checking the nominal mass, the density of steel shall be taken as 0.007 85 kg /mm2 of the cross-sectional area per metre run.

6.2.2. Unless otherwise agreed to between the manufacturer and the purchaser, the tolerances on nominal mass shall be as in Table 2.  For bars / wires whose effective cross-sectional areas is determined as in 5.3.2 (b), the nominal mass per metre run shall correspond to the gross mass and the deviations in Table 2 shall apply to the nominal mass.

Table 2 Tolerances on nominal mass

Nominal size (mm)

Tolerance on the nominal mass, percent

Batch

Individual sample*

Individual sample for coils only†

Up to  and including 10

± 7

- 8

± 8

Over 10 up to and including 16

± 5

- 6

± 6

Over

± 3

- 4

± 4

* For individual sample plus tolerance is not specified.

† For coils batch tolerance is not applicable.

6.2.3. The nominal mass per metre of individual sample, batch and soil shall be determined as given in 6.2.3.1 to 6.2.3.3.

6.2.3.1. Individual sample – The nominal mass of an individual sample shall be calculated by determining the mass of any individual sample taken at random as specified in 10.1 and dividing the same by the actual length of the sample.  The sampled shall be of length not less than 1.5 meter.

6.2.3.2. Batch – The nominal mass of a batch shall be calculated from the mass of the test specimens taken as specified in 10.1 and dividing the same by the actual total length of the specimens.  Each specimen shall be of length not less than 0.6 meter.

6.2.3.3. Coils – The nominal mass of a coil shall be calculated by determining the mass of two samples of minimum one meter length taken from each end of the coil and dividing the same by the actual total length of the samples.

7.  Physical properties

7.1. Proof stress, percentage elongation and tensile strength for all sizes of deformed bars / wires determined on effective cross – sectional area (see 5.3) and in accordance with 8.2 shall be specified in Table 3.

Table 3 Mechanical properties of high strength deformed bars and wires

Sl. 

No.

Property

Grade

Fe 415

Fe 500

Fe 550

1

0.2 percent proof stress / yield stress, Min, N/mm2

415.0

500.0

550.0

2

Elongation, percent, Min, on gauge length 5.65 ÖA, where A is the cross-sectional area of the test piece

14.5

12.0

8.0

3

Tensile strength, Min

10 percent more than the actual 0.2 percent proof stress but not less than 485.0 N/mm2

8 percent more than the actual 0.2 percent proof stress but not less than 545.0 N/mm2

6 percent more than the actual 0.2 percent proof stress but not less than 585.0 N/mm2

7.2. The bars / wires shall withstand the bend test specified in 8.3 and the rebend test specified in 8.4

7.3. Bond – Bars / wires satisfying the requirements given in 4 shall be de4emed to have satisfied the bond requirements of a deformed bar / wire.

8.  Tests

8.1. Selection and preparation of test sample – Unless otherwise specified in this standard, the requirements of IS: 226-1975 shall apply.

8.1.1. All test pieces shall be selected by the purchaser or his authorised representative, either;

(a)from the cuttings of bars / wires ; or (b) if, he so desires, from any bar / wire after it has been cut to the required or specified size and the test piece taken from any part of it. In neither case, the test piece shall be detached from the bar / wire except in the presence of the purchaser or his authorised representative.

8.1.2. The test pieces obtained in accordance with 8.1.1 shall be full s4ections of the bars / wires and shall be subjected to physical tests without any further modifications.  No reduction in siz4e by machining or otherwise shall be permissible, except in case of bars of size 28mm and above (see 8.1.2.1.   No test piece shall be annealed or otherwise subjected to heat treatment except as provided in 8.1.3 Any straightening which a test piece may require shall be done cold.

8.1.3. Notwithstanding the provisions in 8.1.2 test pieces may be subjected to artificial ageing at a temperature not exceeding 1000 C and for a period not exceeding 2 hours.

8.1.4. Before the test pieces are selected, the manufacturer or supplier shall furnish the purchaser or his authorised representative with copies of the mill records giving the mass of bars / wires from that cast can be identified.

8.2.  Tensile test -  The tensile strength, 0.2 percent proof stress and percentage elongation of bars / wires shall be determined in accordance with requirements of IS: 1608-1972 read in conjunction with IS : 226-1975

8.2.1. Alternatively and by agreement between the purchaser and the supplier, for routine testing, the proof stress may be determined in conjunction with the tensile strength test and may be taken as the stress measured on the specimen whilst under load corresponding to an increase measured by an extensometer of 0.4 percent for Fe 415 bars / wires, 0.45 percent for grade Fe 500 bars / wires and d0.47 percent for grade Fe 550 bars / wires the total str5ain on any convenient gauge length.

8.2.2. The stresses shall be calculated using the effective cross – sectional area of the bar / wire.

8.3. Bend best - The bend test shall be performed in accordance with the requirements of IS: 1599 – 1974 and the mandr5el diameter shall be considered to have passed the test if there is no transverse crack in the bent portion.

Table 4 mandrel diameter for bend test

Nominal size mm

Mandrel diameter for different grades

Fe 415

Fe 500

Fe 550

Up to and including 22

3 Ø

4 Ø

5 Ø

Over 22

4 Ø

5 Ø

6 Ø

Where Ø is the nominal size in mm of the test piece.

8.4. Rebend test - The test piece shall be bent to an included angle of 1350 ( see Fig.2 ) using a mandrel of appropriate diameter ( see 8.4.1 ) The bent piece shall be aged by keeping in boiling water ( 1000 C ) for 30 minutes and then allowed to cool.  The piece shall then be bent back to have an included angle of 157½0.  The specimen shall be considered to have passed the test if there is no fracture in the bent portion.

  1.  

The diameter of the mandrel shall be as given below:

Nominal size of specimen

Dia of mandrel for Fe 415 and Fe 500

Dia of mandrel for Fe 550

Up to and including 10 mm

5 Ø

7 Ø

Over 10 mm

7 Ø

8 Ø

8.5. Retest - Should any one of the test pieces first selected fail to pass any of the tests specified in this standard, two further samples shall be selected for testing in respect of each failure.  Should the test pieces from both these additional samples pass, the material represented by the test samples shall be deemed to comply with the requirements of that particular test.  Should the test piece from either of these additional samples fail, the material presented by the samples shall be considered as not having complied with this standard.

9. Routine inspection and testing

9.1. All material shall be subject to routine inspection and testing by the manufacturer or supplier in accordance with this standard and a record of the test results of material conforming to this standard shall be kept by the manufacturer or the supplier. The records shall be available for inspection by the purchaser or his representative.

In the case of material delivered to a supplier, the manufacturer shall supply a certificate containing th results of all the required tests on samples taken from the delivered material.

10. Selection of test specimens

10.1. For checking nominal mass, tensile strength, bend test and rebend test, test specimen of sufficient length shall be cut from each size of the finished bar / wire at random at a frequency not less than that specified in Table 5.

Table 5 Frequency for nominal mass, tensile, bend and rebend tests

Nominal size

Quantity

 

For casts / heats below 100 tonnes

For casts / heats over 100 tonnes

Under 10 mm

1 Sample from each 25 tonnes or part thereof

1 Sample from each 40 tonnes or part thereof

10 mm to 16 mm inclusive

1 Sample from each 35 tonnes or part thereof

1 Sample from each 45 tonnes or part  thereof

Over 16 mm

1 Sample from each 45 tonnes or part thereof

1 Sample from each 50 tonnes or part thereof

10.2. Bond test - The frequency of bond test as required in 4.7 shall be as agreed to between the manufacturer and the purchaser / testing authority.

11. Delivery, inspection and testing facilities

11.1. Unless otherwise specified, general requirements relating to the supply o material, inspection and testing shall conform to IS: 1387-1968. {General requirements for the supply of metallurgical materials (first revision)}

11.2. No material shall be dispatched from the manufacturer's or supplier's premises prior to its being certified by the purchaser or his authorized representative as having fulfilled the tests and requirements laid down in this standard except where the bundle containing the bars / wires is marked with the ISI certification mark.

11.3. The purchaser or his authorised representative shall be at liberty to inspect and verify the steel maker's certificate of cast analysis at the premises of the manufacturer or the supplier.  When the purchaser requires an actual analysis of finished material, this shall be made at a place agreed to between the purchaser and the manufacturer or the supplier.

11.4. Manufacturer's certificate - In the case of bars/wires which have not been inspected at the manufacture's works, the manufacturer or supplier, as the case may be, shall supply the purchaser or his authorized representative with the certificate stating the process of manufacture and also the test sheet signed by the manufacturer giving the result of each mechanical test applicable to the material purchased and the chemical composition, if required.  Each test sheet shall indicate the number of the cast to which it applies, corresponding to the number or identification mark to be found on the material.

12. Identification and marking

12.1. The manufacturer or supplier shall have ingots, billets and bars or bundles of bars / wires marked in such a way that all finished bars / wires can be traced to the cast from which they were made.  Every facility shall be given to the purchaser or his authorized representative for tracing the bars/wires to the cast from which they were made.

12.2. For each bundle / coil of bars / wires a tag shall be attached indicating cast No. / lot No., grade and size.

12.3. Distinguishing mark shall be given to identify the different grades of bar / wire.

12.3.1. Identification marks like brand name, trade mark etc., that are introduced during rolling shall be designed and located in such a manner that the performance in use of the bar is not affected.

12.3.2. Each bundle containing the bars / wires may also be suitably marked with the ISI certification mark in which case the concerned test certificate shall also bear the ISI certification mark.

Note - The use of the ISI certification mark is governed by the provisions of the Indian standards institution (certification marks) act and the rules and regulations made there under.  The ISI mark on products covered by an Indian standard conveys the assurance that they have been produced to comply with the requirements of that standard under a well defined system of inspection, testing and quality control which is devised and supervised by ISI and operated by the producer.  II marked products are also continuously checked by ISI for conformity to that standard as a further safeguard.  Details of conditions under which a license for the use of the ISI certification mark may be granted to manufacturers or processors, may be obtained form the Indian standards institutions.

Annexure 7-A.5

SPECIFICATIONS FOR HOT ROLLED STEEL SECTIONS FOR DOORS, WINDOWS AND VENTILATORS (Extract of IS: 7452-1990)

1. Scope

1.1. This standard lays down the requirements regarding material, nominal dimensions and mass, dimensional and mass tolerances, surface finish and packing for hot rolled steel sections used for doors, windows, ventilators and sashes. 

2. References

2.1. The following Indian Standards are necessary adjuncts to this standard:

IS No

Title

1599: 1985

Method for bend test (second revision)

2830: 1975

Carbon steel billets, blooms and slabs for re- rolling into structural steel (standard quality)

2831: 1975

Carbon steel billets, blooms and slabs for re- rolling into structural steel  (ordinary quality)

6914: 1978

Cast billet ingots and continuously cast billets for rolling into structural steel (standard quality)

3. Terminology

3.1. For the purpose of this standard, the components of doors, windows and ventilators shall be defined as given in 3.1.1 and 3.1.2 and as illustrated in Fig.1.

3.1.1. Sub – dividing Bars - These are vertical bars in a fixed-light or window or ventilator.

3.1.2. Fixed – light - Doors, windows and ventilators where there is no openable shutter.

3.1.2.1. Sub – light - A fixed light above an openable door or window.

3.1.2.2. Side – light - A fixed light of door height to couple with door. 

Fig. 1 - Components of doors, windows and ventilators

4. Designation

4.1. Hot rolled steel sections of the profiles given in Fig.2 shall be designated by letters indicated against each. 

5. Material

5.1. Steel as per IS: 2830-1975, IS: 2831-1975 or concast billets conforming to IS: 6914-1978 shall be used for manufacture of rolled steel sections. 

6. Dimensions and dimensional tolerances

6.1. Dimensions - The dimensions of steel rolled sections when measured in accordance with 6.1.1 shall be as given in Fig.2. 

Fig. 2.1 Hot rolled steel sections

6.1.1. The dimensions of the sections shall be measured at the two ends, leaving 150 mm at the end and at the centre.  The average of three readings shall be taken for conformity.  The measurements shall be given to the nearest 0.1 mm. 

6.2. Dimensional Tolerances

6.2.1. Thickness of the sections - Rolling tolerances on thickness of section shall be ±0.2mm.

6.2.2. Thickness of the sections - A tolerance of ± 0.5 mm shall be permitted on the nominal value of the radii of curvature except where the maximum radii have been indicated. 

Fig. 2.2 Hot rolled steel sections

6.2.3. Other dimensions - Rolling tolerances on dimensions of the sections other than those covered in 6.2.1 and 6.2.2 shall be as under :

Dimension (mm)                         Tolerance (mm)

Up to 10                                             ±0.2

Over 10 and up to 25                         ±0.4

and over 25                                        ±0.6 

Fig. 2.3 - Hot rolled sections

6.2.3.1. Dimensions of the matching portion shown with an asterisk ( * ) in Fig. 2, shall be within ± 0.4 mm tolerance. 

6.2.3.2. The flanges of the sections shall be parallel to obtain correct matching. 

7. Mass and mass tolerance

7.1. Mass - Mass of the various sections per running meter shall be as given against each of the section in Fig.2. 

NOTE: Mass of the section as given have been arrived keeping in view the nominal dimensions of the sections and assuming density of the steel as 7.85 gm/cm2.

7.2. Mass tolerance - Mass tolerance per meter length for the various profiles shall be ± 5 percent of the nominal mass specified for the section.

8. Surface finish  

8.1. The rolled steel section shall be free from rolling defects, such as knot, steep bends, overlaps, waviness on edges, unparallel flanges, rolling marks and shall be suitable for punching and welding or both.  The section shall be straightened by roller straightening machine or any other suitable machine ensuring that twist will not be more than 5 degree over a length of 3 m the section shall be packed in such a way as to avoid damage in transit. 

9. Bend test

9.1. Frequency of test - Bend test shall be conducted at the rate of one test per cast or part thereof rolled continuously.  One additional test shall be made for each class of product and for each variation in thickness. 

9.2. Selection and preparation of test sample

9.2.1.   Test samples shall be prepared from the finished product and full particulars regarding cast number, size and mass of section, in each cast shall be recorded. 

9.2.2. The points from which test samples are taken shall be so located in the production as to yield the clearest possible information regarding properties in the cross-sectional and longitudinal planes. 

9.2.3. Wherever practicable, the rolled surface of the steel shall be retained on the two opposite sides of the test samples.

9.2.4. In case of sections, bend tests are to be carried out on rectangular test samples which, as far as possible, should be of the full thickness of the product.  The rolled surface of the test piece shall be on the outer side of the bend during the test. 

9.2.5. Test samples shall be cut in such a manner that deformation is avoided as far as possible.  If guillotining or cutting by hand or power hacksaw is employed an adequate allowance shall be left for removal by machining. 

9.2.6. Test samples taken from rolled steel which have undergone deformation through bending or twisting shall in all cases be straightening cold.  If the deformation is too severe to allow cold straightening, it is permissible, in the case of materials to be delivered in the annealed or normalized condition, to carry out straightening under the application of heat provided the temperature does not exceed 650°C.  When straightening test samples, care shall be taken to avoid any rise in temperature due to cold working as it may alter the properties of the samples as compared with the finished product which they represent. 

9.2.7. Test samples shall not be annealed or otherwise subjected to heat treatment unless the material from which they are cut is similarly treated, in which case the test samples shall be similarly and simultaneously treated with the material before testing.  Any slight straightening of test samples which may be required shall be done cold.

9.3. Bend test piece

9.3.1. The test pieces shall be cut lengthwise.

9.3.2. In all bend test pieces, the rough edge or arris resulting from shearing may be removed by filling or grinding or machining, but the test pieces shall receive no other preparation. 

9.3.3. The test pieces shall not be annealed or otherwise subjected to heat treatment unless the material from which they are cut is similarly treated, in which case the test pieces shall be similarly and simultaneously treated, with the material before testing. 

9.4. Bend test on the test piece shall be conducted in accordance with IS: 1599-1985.  The test piece when cold shall without fracture be doubled either by pressure or by blows from a hammer until the internal diameter is not greater than three times the thickness of the test piece and the sides are parallel. 

9.5. Re–test - Should any one of test pieces first selected fail to pass bend test specified in this standard two further samples shall be selected for testing.  Should the test pieces from both these additional samples pass, the material represented by the test samples shall be deemed to comply with the requirements of bend test.  Should the test pieces from either of these additional samples fail, the material represented by the test samples shall be considered as not having complied with this standard.

10. Packing

10.1. The rolled sections shall be supplied in bundles, each carrying a metal tag with the following information: (a) Indication of the source of manufacture,(b) Designation of the section,(c) Number of pieces in the package, and (d) Batch number. 

10.2. Each bundle shall weigh not more than 100 kg and the variation of any tow bar lengths in a bundle shall not be more than 150 mm. 

11. Marking

11.1. Each length of section shall be indelibly marked at intervals of not more than one meter and shall carry the indication of the source of manufacture. 

Annexure   A   Purpose or recommended use of sections

Designation

of sections

Situation of uses

Designation 

of sections

Situation of uses

T2  T3

Vertical and horizontal glazing bars for doors and sashes, windows, ventilators glazing bars for door side-lights, sub dividing bars, Fir fixed-lights, sash bars for doors, windows and ventilators where steel, aluminium or wooden beading is used for fixing glasses.

F 500, F501, F502

b) F5 is sometimes used as inner frame for open-out windows.  Also used as inner frame for bottom-hung ventilators.

c)  F8 is also used as outer frame for bottom-hung ventilators.

T6

Vertical and horizontal glazing bar for windows and ventilators.

 

Outer or inner frames of large size windows only (more than 600 meter width).

F2

Inner frames for open-in windows.

F 503

Outer frame for large size fixed glazing only.

F3

Outer frames for open-in frames.

F4B

Central mullion (meeting bar for shutters) for windows and ventilators, outer frame for open-in.

F5, F8

a) Inner and middle frames in centre hung ventilators, windows in rainy areas, sub-dividing bars for openable windows and top-hung ventilators.

 

a)  Vertical coupling mullion for all standard-windows.

F7D

Inner and outer frames for windows and ventilators, for inner frames for centre-hung ventilators, and outer frames for door side-lights.

 

b) Can be used as horizontal coupling bar when openable windows are to be coupled above fixed ones one or between two fixed window.

FX6, FZ5

Inner frames for doors.

 

c)  Can also be used as horizontal coupling mullion where windows are not exposed.

FX8

Outer frames for doors.

K12B

To weather Horizontal coupling mullion, also known as weather bar.  Especially used when the coupled unit is exposed to rain.

EZ7

Used as outer frame for industrial sashes.  Also used for outer frame for wooden doors.

 

 

Annexure 7-A.6

SPECIFICATION FOR STEEL DOORS, WINDOWS AND VENTILATORS 

(Extract of IS: 1038-1983)

1. Scope

1.1. This standard lays down the requirements regarding material, fabrication and finish of steel doors, windows, ventilators and fixed-lights manufactured from rolled steel sections to specified sizes and designs.

1.2. This standard does not cover steel doors, windows, ventilators and fixed lights for use in industrial buildings. 

2.  Terminology 

2.1. For the purpose of this standard, the components of doors, windows, ventilators and fixed-lights shall be as defined in 2.1.1 to 2.1.2.2 and as illustrated in Fig.1. 

2.1.1. Sub-Dividing Bars – These are vertical bars in a fixed-light or window or ventilators.

2.1.2. Fixed – Light - Doors, windows and ventilators where there is no openable shutter.

2.1.2.1. Sub – Light – A fixed-light above openable door or window.

2.1.2.2. Side – Light – A fixed-light of door height to couple with door. 

3.  Symbolic designation

3.1. The direction of closing and faces of doors, windows and shutters shall be designated in accordance with IS 4043 – 1969.

4.  Standard sizes, tolerances and designations

4.1. Sizes – Types and overall sizes of steel doors, windows, ventilators and fixed lights shall be as given in Fig.2.  ‘Sizes other than modular sizes, as agreed to between the manufacturer and the purchaser, may also be permitted’.

4.1.1. The dimensions shown in Fig.2 are overall heights and widths to the outside of frames of steel doors, windows, ventilators and fixed-lights.  These sizes are derived after allowing 10 mm clearance on all the four sides for the purpose of fitting doors, windows, ventilators or fixed-lights into modular openings (see Fig.3). 

4.2. Tolerances – The sizes Indicated in Fig.2 for door, window and ventilator or fixed-light frames shall not vary by more than ± 1.5 mm.

4.3. Designation – Doors, windows, ventilators and fixed-lights shall be designated by symbols denoting their width, type and height in succession in the following manner:

a) Width – It shall be indicated by the number of modules in the width of opening.

b) Type – It shall be indicated by the following letters of alphabet: C = Centre hung shutter, F = Fixed glass panes, H = with horizontal glazing bars,  N = without horizontal glazing bars, S = Side hung shutters, and  T = Top hung shutters.

c) Height – It shall be indicated by the number of modules in the height of opening. 

Example:

A window of a width of 10 modules and height 12 modules having horizontal glazing bars and side hung shutters is designated by 10HS12.

4.3.1. Composite doors, windows, ventilators or fixed-lights shall be designated in the following manner:

a) A 12 module wide and 21 module high horizontally glazed side hung door coupled on its two sides with two sides hung horizontally glazed windows, 6 module wide and 12 module high is designated by 6HS12 /12HS21 / 6HS12.

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

10HF6 / 10HF6.   

10HS12/10HS12 

4.4. The purchaser shall supply the information as given in Appendix A while placing order for steel doors, windows, ventilators and fixed-lights. 

5.1. Rolled steel sections

5.1.1. Rolled steel sections for the fabrication of steel doors, windows, ventilators and fixed-lights shall conform to IS: 7452-1982.  Steel used in the manufacture of these sections shall conform to IS: 7452 – 1982. 

5.2. Coupling sections for non-modular openings

5.2.1. Coupling section K11B shall be used as mullions for coupling the units side by side and coupling section K12 B to couple independent units one above the other.  These sections are covered in IS: 7452 – 1982.

5.2.2. Coupling sections manufactured from galvanized steel plate of minimum 1.6 mm thickness conforming to the dimensions shown in Fig.4 may also be used for coupling if agreed to between the purchaser and the manufacturer.

5.  MATERIALS

5.2.3. Tubular section shall be used for coupling at varying angles to form bay composites, right angle composites, etc.  (See IS: 1081-1960)

 5.3. Glass panes – Glass panes shall be at least 3 mm thick and shall conform to IS: 2835-1977.  All glass panes shall have properly squared corners and straight edges.  The sizes of glass panes for doors, windows, ventilators and fixed-lights shall be as given in Table 1.  Note - The sizes of glass are only indicative and approximate and may vary depending on the tolerances in the doors, windows, ventilators and fixed-lights. 

Fig. 1 Terminology for steel doors, windows and sub-light

5.4. Screws – Screw threads of machine screws used in the manufacture of steel doors, windows, ventilators and fixed-lights shall conform to the requirements of IS: 4218 (Part I) – 1976, IS : 4218 (Part II) – 1976, IS : 4218 (Part III) – 1976, IS : 4218 (Part IV) – 1976, IS : 4218 (Part V) – 1967 and IS : 4218 (Part VI) – 1978.

5.4.1. Fixing lugs shall have a standard slot of 8 mm wide for mild steel screw of 6 mm dia and 12 mm long with square nuts as indicated in Fig. 3.

Fig. 2-A Doors (as viewed from inside)

Fig. 2-B Windows

* * * *