Construction specification, documentation and traceability

The construction specification sits at the centre

AS/NZS 5131 does not work on its own. Clause 4.1.1 requires every piece of information needed to build the works to be set out clearly in the construction specification, and requires procedures for handling variations to it and for resolving discrepancies or inconsistencies within it. Where relevant, the specification has to cover:

• design data and details to the extent required by AS 4100, AS 5100.6 or NZS 3404;
• the required information, selected options and assigned responsibilities from Appendix B (Paragraphs B1–B3);
• the construction category (see construction categories);
• any changes to the Appendix F tolerances, any AESS requirements and any special fabrication or erection requirements;
• who is responsible for managing compliance, plus Appendix I information for New Zealand.

Clause 4.1 also introduces treatment grades P1–P3 for surfaces to be painted (Clause 4.1.3, defined in Clause 9.8.4) and the three types of geometrical tolerance – manufacturing, fabrication and erection – some of which are essential tolerances because the design capacity depends on them (Clause 4.1.4).

The construction specification governs each project. A fabricator's certification demonstrates capability; it does not replace the project's own requirements.

Design stages and BIM

Clause 4.2 distinguishes the erection design stage (how the structure performs while it is being built – see Section 11) from the in-service design stage, whose usual output is the construction specification. Temporary stability during erection is therefore a design matter that must be assigned, not left to chance.

Where the specification calls for BIM or other digital project models, Clause 4.3 requires the process, software, hardware and competent personnel to be documented, and treats the digital model as fabrication documentation. Key issues to settle include a fabrication model consistent with the design model, ownership of the design model and responsibility for its accuracy, an open exchange format where practical (the Standard gives ISO 16739 – IFC – as an example), and version control with a recorded review, approval and release before shop detailing. See BIM, IFC and shop drawings.

Shop detailing documentation

Who prepares and who reviews shop drawings must be stated in the construction specification (Clauses 4.4.1 and 4.4.4). Clause 4.4.2 expects the drawings to show, in conventional AS 1100 drafting form, complete information on every assembly, component and connection. In summary that information falls into five groups:

• Identity and material – marks, steel type and grade, dimensions and camber.
• Fabrication – forming and heat treatment where applicable, weld and bolt locations, sizes and categories.
• Protection – surface preparation, coating system and coating-related detailing.
• Handling and erection – lifting points, temporary bracing, assembly and erection procedures, member orientation.
• Set-out and testing – grid and level set-out, marking plans for holding-down bolts and anchors, and any engineer-nominated testing.

Clause 4.4.3 requires a drawing numbering system that stays traceable for the life of the works, uniquely identified and dated revisions with the scope of each revision stated, and a written record of every RFI and its response. Reviewed drawings should be marked "approved" or "approved subject to corrections" by the nominated competent person. See World Steel's shop drawing service.

Quality documentation and the quality plan

For every category except CC1, Clause 4.5.1 requires documented quality arrangements: allocation of tasks and authority, procedures and work instructions, a works-specific ITP, procedures for changes, nonconformities, concessions, quality disputes, document and record control, corrective and preventive action and audits, a contractual and technical review of requirements, and – importantly for offshore supply – hold points, witness inspections and the access they require. The Standard notes that Clause 5 of the ISO 3834 series can be used to meet the contract and technical review requirements.

Clause 4.5.2 makes a quality plan mandatory at CC3 and CC4 (and for coating quality level PC2); at CC2 it depends on the specification. The plan reviews the specification against process capability, names the organisation and responsible managers, allocates each inspection task, and confirms that records for a hold point are produced before that hold point is released. Appendix E gives recommended content.

Section 4 closes with three further duties: identify and manage the hazards of fabrication, welding, coating, bolting and erection (Clause 4.5.3); keep enough as-built records to show the works match the specification (Clause 4.5.4); and document decisions, including the basis and qualifications of any competent person's judgement (Clause 4.5.5).

Purchasing and subcontracted services

Clause 4.6.1 requires a documented purchasing procedure, run by a named person, that can track supplier performance trends. Purchase orders must carry the requirements that matter: approvals, personnel qualifications, quality system requirements, the construction category and any verification at the supplier's premises. Purchased product must then be verified, for example through supplier assessment, approved supplier lists and receiving inspection.

For components – steel, plate, assemblies, bolts and consumables – Clause 4.6.2 requires the documentation needed to satisfy Clause 5.2 to be obtained at purchase, preferably as a Supplier Declaration of Conformity. For subcontracted services such as drafting, cutting, welding, painting, galvanizing or erection, Clause 4.6.3 requires the main contractor to give the subcontractor all the information it needs and to collect full records proving compliance at the designated CC. The subcontractor must meet the Standard for its scope.

Three levels of traceability (Clause 4.7)

All three require material identification to be transferred when offcuts return to stock and before they are allocated to another job. Which level applies is set through Clause 5.2.3 and the specification (an option listed in Appendix B2); see materials and traceability.

Appendix B – a checklist for the specifier

Appendix B is normative: it is the map of everything the specification must or may define. Rather than repeat its long tables, the structure is:

For buyers, B1–B3 make a useful tender-stage gap check. Refer to the current edition of AS/NZS 5131 for the full requirements.

What this means for offshore fabrication

For a Vietnamese fabricator supplying Australian projects, Section 4 is mostly about evidence. The specification gaps that a local fabricator might resolve by phone have to be closed through a written RFI log. Hold points need practical inspector access – on site or remotely. Mill certificates, ITP records and the as-built dossier must be in English and must link back to piece marks. Subcontracted processes such as hot-dip galvanizing come under the fabricator's purchasing controls.