SPECIFICATION AND STANDARD FOR STRUCTURAL STEELWORK: GENERAL PART 1

1.0            STRUCTURAL STEELWORK

1.1            GENERAL

1.1.1         This  Specification  shall  be  read  in  conjunction  with  the  General  Conditions  of

Contract and all other Specifications and Drawings.

1.1.2         Where works are ordered to be performed by the Contractor but are not specified in these Specifications, the Contractor shall carry them out with full diligence and expedience as are expected for works of this nature.

1.1.3         This part of the Specification sets out the requirements for:

(a)    the fabrication, supply and delivery of all structural steel used in the Contract; (b)    the assembly and erection of structural steel including surface preparation and

corrosive protection measures.

(c)    Quality Assurance and Quality Control of the materials.

1.1.4         An  independent  organisation  known  as  the  Independent  Testing  Agency  (ITA), approved by the Client / SCI, shall carry out tasks to ensure that:

(a)    The Contractor’s proposed methods are likely to produce acceptable work. (b)     Finished items and assembly conform to the Specifications.

1.1.5         The duties of the ITA are described in the Quality Assurance/ Quality Control section of the Specifications and they include the carrying out of non-destructive testing in addition to that carried out by the Contractor.

1.2            DEFINITION

The following definition shall be adopted in this specification.

“SCI”                          Sembcorp Industries Ltd and its appointed QP (Supervision); Resident

Technical Officer; and Engineers.

“Contractor”               Individual, firm or corporation appointed by SCI to execute and complete the scope of work defined in the Agreement.

“Scope of work”         The work (activities) assigned to the Contractor via formal execution of the Agreement.

“Site”                          Any site where the Scope of work is to be performed or any structure is to be located.

“Agreement”               The legal agreement between SCI and Contractor to perform the scope of work defined in this document; including but not limited to the

Condition of Contract, Purchase Order, Letter of Intent, Letter of Award, Variation Order and other relevant documents between SCI and other parties

1.3            REFERENCE DOCUMENTS

1.3.1         Unless otherwise specified herein, the following Codes and Standards current at the date of the tender shall lay down the minimum standards required for the structural steelwork.   Where these Codes and Standards are in conflict, or are less severe than the equivalent provisions of the Singapore Standards, the latter standards shall take precedence.

1.3.2         Standards, Specifications and test methods are referred to in abbreviated form (e.g.

BS 4). For convenience, the full titles are given below:

ANSI/AWS D1.1       Structural Welding Code – Steel, American Welding Society

ASTM E165              Standard test method for liquid penetrant examination

BS 4                         Structural Steel Sections, Specifications for Hot Rolled Sections

BS 1070                   Specification for Black Paint (tar-based)

BS 1140                   Specification for  Resistance Spot Welding  of  Uncoated  and

Coated Low Carbon Steel

BS 2523                   Specification for Lead-based Priming Paints

BS 3416                   Specification for Bitumen-based Coatings for Cold Application, Suitable for use in Contact with Potable Water

BS 3692                   Specification for ISO metric-precision Hexagon Bolts, Screws

and Nuts. Metric Units

BS 4147                   Specification for Bitumen-based Hot-applied Coating Materials for Protecting Iron and Steel, including Suitable Primers Where

Required

BS 4164                   Specification for Coal-tar-based Hot-applied Coating Materials for Protecting Iron and Steel, Including a Suitable Primer

BS 4190                   Specification for ISO metric Black Hexagon Bolts, Screws and

Nut

BS 4320                   Specification  for  Metal  Washers  for  General  Engineering

Purposes. Metric Series

BS 4360                   Specification for Weldable Structural Steels

BS 4395                   Specification   for   High   Strength   Friction   Grip   Bolts   and

Associated Nuts and Washers for Structural Engineering

BS 4592                   Industrial type flooring and stair treads.

BS 4604                   Specification for the Use of High Strength Friction Grip Bolts in

Structural Steelwork. Metric Series

BS 4620                   Specification for Rivets for General Engineering Purposes

BS 4871                   Specification   for   approval   testing   of   welders   working   to approved welding procedures.

BS 4872                   Specification  for  approval  testing  of  welders  when  welding

procedure approval is not required.

BS 4933                   Specification for ISO metric black cup and countersunk head bolts and screws with hexagon nuts

BS 5395                   Stairs, ladders and walkways

BS 5400                   Specifications for Materials and Workmanship: Steel

BS 5606                   Guide to Accuracy in Building

BS 5950                   Structural Use of Steelwork in Building

BS 6072                   Method for magnetic particle flaw detection. BS 6150                   Code of Practice for Painting of Buildings

BS 7079                   Preparation of Steel Substrates Before Application of Paint BS

7361 Cathodic Protection

BS EN 13636           Cathodic  Protection  of  Buried  Metallic  Tanks  and  Related

Piping

BS 7668                   Specification  for  Weldable  Structural  Steels.  Hot  Finished

Structural Hollow Sections in Weather Resistant Steels.

BS EN 440               Welding consumables. Wire electrodes and deposits for gas shielded metal arc welding of non-alloy and fine grain steels

BS EN 756               Welding consumables. Solid wires, solid wire-flux and tubular

cored electrode-flux combinations for submerged arc welding of non alloy and fine grain steels

BS EN 760               Welding consumables. Fluxes for submerged arc welding

BS EN 970               Non-destructive    examination    of    Fusion    Welds.    Visual

Examination

BS EN 1011             Welding. Recommendations for welding of metallic materials

BS EN 1435             Non-destructive     examination     of     welds.     Radiographic examination of welded joints

BS EN 1668             Welding consumables. Rods, wires and deposits for tungsten inert gas welding of non alloy and fine grain steels

BS EN 1714             Non destructive testing of welded joints. Ultrasonic testing of welded joints.

BS.EN 10025           Hot rolled products of non-alloy structural steels – Technical

delivery conditions

BS EN 10029           Specification for Tolerances on Dimensions, Shape and Mass for Hot-rolled Steel plates 3 mm Thick or Above

BS EN 10034           Structural  steel  I  and  H  section.  Tolerance  on  shape  and

dimensions

BS EN 10055           Hot rolled steel equal flange tees with radiused root and toes.

Dimensions and tolerances on shape and dimensions

BS EN 10056           Specification for structural steel equal and unequal angles

BS EN 10113           Hot Rolled Products in Weldable Fine Grain Structural Steels

BS EN 10155           Structural   Steels   with   Improved   Atmospheric   Corrosion

Resistance. Technical Delivery Conditions

BS EN 10210           Hot Finished Structural Hollow Sections of Non-alloy and Fine

Grain Structural Steel

BS EN 10219           Cold formed welded structural hollow sections of non-alloy  and fine grain steels.

BS EN 10255           Non-alloy  Steel  Tubes  Suitable  for  welding  and  Threading.

Technical Delivery Conditions

BS EN 10279           Hot rolled steel channels. Tolerances on shape, dimension and mass

BS EN ISO 1461      Hot  dip  galvanized  coatings  on  fabricated  iron  and  steel

articles. Specifications and test methods

BS EN ISO 898        Mechanical properties of fasteners made of carbon steel and alloy steel. Bolts, screws and studs

BS EN ISO 2560      Welding consumables. Covered electrodes for manual metal

arc welding of non-alloy and fine grain steels

BS EN ISO 9002      Quality Systems. Model for quality assurance in production, installation and servicing.

BS EN ISO 9934      Non-destructive testing. Magnetic particle testing.

BS EN ISO 12944    Paints and Varnishes. Corrosion Protection of Steel Structures by Protective Paints Systems.

BS EN ISO 14713    Protection against corrosion of iron and steel in structures. Zinc and Aluminium coatings

SS 494                     Lead and chromate-free primer for iron and steel substrates SS 5                         Methods of Test for Paints, Varnishes and Related Materials SS 6                         Red Lead Based Primers for Iron and Steel Surfaces

SS 7                         Paint: Finishing, Gloss Enamel

SS 34                       Undercoat Paint for Gloss Enamel

SS 104                     Cold-formed steel sections for general structures

SS 470                     Hot-finished  structural  hollow  sections  of  non-alloy  and  fine grain structural steels

SS 510                     Code of Practice on Safety in welding and cutting (and other

operations involving the use of heat).

SS503                      Cold formed welded steel structural hollow sections.

SS CP 8                   Use  of  Manual  Metal-arc  Welding  in  the  Steel  Building

Construction

SIS 05 5900             Swedish Standard for method of surface preparation

1.4            QUALITY OF STRUCTURAL STEEL

1.4.1         Standards

1.4.1.1      The material for all structural steelwork shall comply with BS 4360, BS 7668, BS EN

10029, NS EN 10113, BS 10155 and BS 10210, as appropriate.

1.4.2         Materials

1.4.2.1      The steel fabricator should have been accredited with appropriate category from the structural steel fabricators accreditation scheme managed by the Singapore Structural  Steel Society for the work to be undertaken by him.

1.4.2.2      The manufacturer shall produce a factory production control (FPC) certificate issued by an independent third-party certification agency acceptable to or recognized by BCA as an attestation of this factory production control system.  The manufacturer shall  produce  an  authenticated  test  certificate  containing  information  stated  in

Section 3 .2 of BC1:2008.

1.4.2.3      In accordance to BC1:2008, all structural steel including fasteners procured from manufacturers without a ‘Factory Production Control Certificate’ shall be deemed as

Class ‘2’ and  would require material test certificates (MTC) from an accredited

laboratory under the Singapore Laboratory Accreditation Scheme (SINGLAS) or other laboratories accredited under a mutual agreement with SINGLAS.

1.4.2.4      All structural steel including fasteners procured for the project shall be Class ‘1’as stated in BC1:2008.

1.4.2.5    Appropriate sample testing and test methods are given in Appendix B of BC1:2008.When the limiting values are not given in Section 2.0 of BC1:2008, linear interpolation shall be allowed to determine the limiting value for the test parameters of interest.

1.4.2.6      Structural steel and structural tubing shall conform to the following specification unless specified otherwise on drawings:

a) Structural steel: BS.EN 10025: 1993

Internal Conditions:    Grade S275JR for material up to 25mm thick

Grade S275J0, for material 26mm - 60mm thick

External Conditions:   Grade S275JR, for material up to 15mm thick

Grade S275J0, for material 16mm - 40mm thick

The above thicknesses are based on factor K = 1 in clause 2.4.4.3 of BS 5950 and may be increased on investigation if conditions are such that K = 2

b) Structural tubing: BS.EN 10210: Part 1. Grade S275J2H

Hot-rolled steel shapes shall conform to BS 4 or BS EN 10056, as appropriate.

1.4.2.7      Welding  consumables  shall  produce  welds  with  strength,  ductility  and  notch toughness properties at least equal to those specified for the base metal being welded.   Electrodes shall be compatible with the welding process selected and in accordance with BS EN ISO 2560, BS EN 756 as appropriate. All welding shall be in accordance with BS EN 1011.

1.4.2.8      Certified  mill  test  reports,  including  impact  and  ultrasonic  test  results,  shall  be furnished as required, to verify that materials meet applicable specifications.

1.4.2.9      Chequered floor plates shall be 8mm minimum thickness unless specified otherwise on drawings.

1.4.2.10    Unless otherwise stated, the minimum thickness of steel shall be 7.8mm with the exception of beam webs, joists webs and channel webs.

1.4.2.11    Rolled sections shall be straight and in accordance with tolerances stated in BS 4 or

BS EN 10056.  Plates shall be flat, true and supplied without burred edges.

1.4.2.12    Open mesh floor (grating) shall be of carbon steel and conform to BS EN 10029, BS

7668, BS EN 10113, BS EN 10210, Grade S275

1.4.2.13    Steel permanent shuttering shall be of material conforming to BS EN 10147 and

BS EN 10025.

1.4.2.14    Bolts

Precision bolts shall conform to BS 3692.

All bolts shall be grade 8.8 and shall conform to BS 3692 but with dimensions, tolerance and thread length to BS 4190.

1.4.2.15    Washers shall conform to BS 4320.

1.4.2.16    Surface Condition

Steel for fabrication is not to be more heavily pitted or rusted than Grade C of BS

7079 Part Al.

For hot rolled plates and wide flats, if there are surface imperfections and defects as classified in BS EN 10163-2 Clause 4 (Requirements) revealed during  surface preparation, rectify the surface in accordance to BS EN 10163-2 Clause 5 (Repair Procedures).

For hot rolled sections, if there are surface imperfections and defects as classified in BS  EN 10163-3 Clause  4 (Requirements) revealed  during  surface  preparation, rectify the surface in accordance to BS EN 10163-3 Clause 5 (Repair Procedures).

For hot rolled hollow sections, rectify the surface imperfections and defects revealed during surface preparation in accordance to BS EN 10210-1 Clause 6.8 (Surface Condition).

1.4.2.17    Profiled Steel Decking

All Profiled Steel Decking shall comply with BS 5950-4 Clause 3.1 unless otherwise agreed.

1.4.2.18    Protective Finishes

All Galvanising Materials shall comply with BS EN ISO 1461. All Sherardised Coatings shall comply with BS 4921.

All Metallic Blast Cleaning Abrasives shall comply with BS 7079-E2 for chilled iron grit and comply with BS 7079-RE3 for cast steel grit.

If required, submissions of  revised review shop drawings to SCI shall continue promptly until a “No Comment” stage is reached.

1.4.2.19    For all main structural connections, a minimum bolt size of M16 shall be used.  No bolt size less than M12 shall be used for connecting structural sections unless otherwise shown on drawings.

1.4.2.20    All steelwork shall be designed / detailed to assist in maintaining  the structure throughout its life.  All pockets giving rise to dust traps shall be eliminated if possible. Where possible, details shall ensure that all surfaces shall be readily accessible for future painting.

1.4.2.21    Stanchions  may  not  be  spliced  at  positions  other  than  those  indicated  on arrangement drawings, without prior approval from SCI.

1.4.2.22    No additional splices or butt welds shall be incorporated without prior approval from

SCI.

1.4.2.23    Bolted connections shall not be detailed which use mixed types/ grades of bolts.

1.4.2.24    A minimum of four bolts shall be used for each beam-to-beam and beam-to- column connection, unless shown otherwise. A minimum of two bolts shall be used for all other connections.

1.4.2.25    All connections between structural members shall be made using grade 8.8 bolts.

Grade 4.6 bolts may be used for attaching non structural elements such as handrail standards etc..

1.4.2.26    All bolts shall be supplied with galvanized finish.

1.4.2.27    The Contractor shall submit to SCI for review, two copies of his fabrication drawings marking plans and drawing register completed to the agreed Quality Assurance procedures. The drawing register should be issued at least every 7 days or sooner if required. The Contractor shall allow a minimum of seven working days for this review to be carried out and shall forward drawings to be reviewed as they become available but in a timely manner in agreement with the contract programme and allow SCI to utilise his resources in an efficient manner.

1.4.2.28    If required, the submissions to SCI the revised drawings for review, shall continue until a “No Comment” stage is reached.

1.4.2.29   When the status of each fabrication drawing has been agreed as “Issued For Construction” the Contractor shall immediately re-issue the drawing recording the status as “Issued for Construction”.

1.4.2.30    The Contractor shall be responsible for the correctness and completeness of his shop drawings. Review and approval from SCI does not relieve the Contractor of his full responsibility for any discrepancies, errors or omissions therein. The Contractor shall bear all costs related to the site remedial measures should there be inconsistencies or errors in the shop drawings after the comments/ approval have been given by SCI.

1.4.2.31    The Contractor may propose alternative details if he considers that the typical details shown on SCI's drawings do not suit his particular methods of fabrication, transport or  erection.   Alternative details shall not  be incorporated  in the  shop drawings without the prior approval in writing from SCI.  All alternative proposal/ details shall be accompanied by detail connection design duly endorsed by a Registered Professional Engineer in Singapore appointed by the fabricator.

1.4.3         Copies of Orders

Two copies of all orders and suborders placed by the Contractor shall be forwarded to SCI.

1.4.4         Marking of Steel

1.4.4.1      Steel shall be marked in accordance with BS 4360. Where steels of different grades are used they shall have additional markings approved by SCI.

1.4.5         Storage, Handling And Transportation

1.4.5.1     All structural steels, before and after fabrication, shall be stored, handled and transported by approved means to avoid excessive stresses, deformation, damage and risks to corrosion.  The steels shall be stored clear of the ground on concrete or timber floor under cover and well protected from the effects of  weather unless otherwise agreed by SCI.

1.4.6         Commencement of the Work

1.4.6.1      No item of work shall be commenced until the results of any related preliminary tests and shop drawings required by the Contract specification have been approved by SCI.

1.4.6.2      The Contractor shall commence work upon obtaining the Approvals and Permit to Commence Work from the authorities.  Any standby cost arising from this shall be deemed to have been included in the price.