A.C. Steel — Structural Steel Fabricators Melbourne logo
0431 885 854

AS 4100 Compliance for Melbourne Structural Steel

Australia's structural steel design standard - explained for the builders, architects, and owners who need to verify a fabricator is actually compliant, not just claiming it. Built by A.C. Steel, AS 4100 fabricator & installer since 2017.

AS 4100:2020 Current Edition AS/NZS 1554.1 SP Welding Melbourne VBA-Ready Documentation
Call 0431 885 854

Get Our AS 4100 Compliance Pack

Everything your building surveyor needs, in one PDF:

  • Mill certificates checklist
  • Welder qualification records
  • Weld procedure specifications
  • Inspection & test plan template
  • Certificate of Compliance sample
See What's Included
Or call 0431 885 854 to discuss your project
AS 4100:2020
Current Edition
Superseded AS 4100:1998
5
Sibling AS Standards
5131 / 1554 / 3679 / 1163 / 1170
CC1-CC4
Construction Categories
Per AS/NZS 5131
SP / GP
Welder Qualifications
AC Steel welds SP by default

What Is AS 4100?

AS 4100 is the Australian Standard for structural steelwork design. It sets the requirements for how load-bearing steel structures - beams, columns, portal frames, connections - must be designed, fabricated, erected, and modified.

AS 4100 was first published in 1990, most recently revised in 2020 (AS 4100:2020). It sits alongside AS/NZS 1170 (structural design actions) and AS/NZS 5131 (construction categories & quality) as the three-pillar backbone of Australian structural steel engineering. If a project uses structural steel, AS 4100 applies - full stop.

The standard covers limit-state design methodology, member capacity calculations (bending, shear, compression, tension), connection design (bolted, welded), fatigue considerations, and requirements for fabrication tolerances and erection procedures. It is the reference structural engineers cite in every certification, and the framework building surveyors verify against.

The AS 4100 Standards Family

AS 4100 doesn't stand alone. Compliance on a Melbourne project means coordinating five standards that reference each other. Here's the map:

AS 4100:2020

Structural Steel Design

Design methodology, member capacity, connections, fabrication tolerances.

Primary
AS/NZS 5131

Construction Categories

Quality framework - CC1 to CC4 based on project risk. Most residential/commercial = CC1-CC2. Read our CC guide →

AS/NZS 1554

Welding

Part 1 covers structural steel welding, SP (Structural Purpose) and GP (General Purpose) categories.

AS/NZS 3679

Hot-Rolled Sections

Material spec for UB, UC, PFC, EA, UA sections. Grade 300 (300PLUS) is standard.

AS/NZS 1170

Structural Actions

Dead loads, live loads, wind, snow, earthquake - the input side of every AS 4100 calculation.

Have a project already? We'll check compliance against all 5 standards for you.
Call 0431 885 854 Send Drawings

Limit-State Design in Plain English

AS 4100 uses limit-state design: check the structure against two failure modes with different safety factors. Here's what those actually mean.

Ultimate Limit State (ULS)

"Will it stay standing under the worst case?"

ULS checks that the structure won't collapse under peak loads - the worst combination of dead load, live load, wind, and earthquake it will ever face. AS 4100 requires the steel section's capacity to exceed these factored loads with margin.

  • Load factors come from AS/NZS 1170.0 (e.g. permanent ~1.2, imposed ~1.5, plus wind and earthquake combinations)
  • Capacity reduction (φ) is typically 0.9 for bending and axial members, 0.8 for bolted connections - always verify against AS 4100 for your specific member and design action
  • Consequence: If ULS fails, the structure could collapse. Non-negotiable.

Serviceability Limit State (SLS)

"Will it work day-to-day without cracking finishes?"

SLS checks the structure stays comfortable and functional under everyday loads. Deflection limits stop beams from sagging enough to crack plasterboard, tiles, or window seals.

  • Typical deflection limits: ~span/300 to span/500 depending on element, per AS/NZS 1170.0 Appendix C guidance
  • Vibration: floors must feel solid under foot traffic (relevant for long spans)
  • Consequence: If SLS fails, occupants get cracked finishes and bouncy floors - annoying, not catastrophic.

Member Design Essentials

Every structural steel element in your project sits under one of these three clauses. Here's what the fabricator must design and verify for each.

Beams (Bending & Shear)

Horizontal members carrying vertical loads. Section capacity depends on flange width-to-thickness (compact vs slender), lateral restraint, and load location.

Common members: UB (universal beam), PFC (parallel flange channel), RHS (rectangular hollow section). See our beam fabrication service →

AS 4100 Cl. 5

Columns (Compression)

Vertical members carrying axial compression. Design accounts for buckling (Euler + combined bending), slenderness ratios, and effective length depending on end restraints.

Common members: UC (universal column), SHS (square hollow section), CHS (circular hollow section). Structural steel overview →

AS 4100 Cl. 6

Connections (Bolted & Welded)

Where members meet - flexible end plates, welded moment connections, base plates, splices. Design capacity governs failure hierarchy: connection should never fail before the member.

Bolts to AS 4100 Section 9; welds cross-reference to AS/NZS 1554.1. How fabrication works →

AS 4100 Cl. 9

Welding to AS 4100 + AS/NZS 1554.1

AS 4100 references AS/NZS 1554.1 for weld design and qualification. The critical distinction: SP (Structural Purpose) versus GP (General Purpose). This decides who can legally weld your beams.

Structural

SP - Structural Purpose

Required for load-bearing welds

Welders qualified under AS/NZS 1554.1 SP have completed documented procedure qualification tests. Their welds are traceable, inspected, and suitable for load-carrying structural elements.

General

GP - General Purpose

Non-structural applications only

GP-qualified welds are for non-load-bearing applications - handrails, decorative elements, minor brackets. GP is not acceptable for members that AS 4100 designs for capacity.

  • Handrails, balustrades (decorative sections)
  • Cover plates, minor brackets
  • Non-structural steel work
  • Never for AS 4100 structural elements
Need SP-welded structural steel? A.C. Steel welds SP by default on every job.
Call 0431 885 854 See Fabrication Services

Buyer's AS 4100 Compliance Checklist

If you're a builder, architect, or building owner - not an engineer - here's exactly what to ask your fabricator for to verify they're actually AS 4100 compliant, not just claiming it.

What Every AS 4100 Fabrication Should Provide

6 items

1. Mill Certificates for Steel Sections

Traceability documents from the steel mill (e.g., BlueScope, InfraBuild) proving material grade (Grade 300 / Grade 350) and chemical composition per AS/NZS 3679. Every UB, UC, PFC on your project should tie back to a specific heat number.

2. Welder Qualification Records (WQR)

Certificates showing each welder is qualified to AS/NZS 1554.1 SP for the process (MIG/TIG/stick), position, and material thickness they're welding on your project. Not expired. Named individuals, not just "our welders are certified".

3. Weld Procedure Specifications (WPS)

Documented procedures for each joint type on your project - filler metal, current settings, joint prep, sequence. These are the recipes welders follow. A fabricator without WPS documents is winging it.

4. Inspection & Test Plan (ITP)

A schedule showing when and how welds and fabricated components will be inspected before leaving the workshop and on installation. Aligns with AS/NZS 5131 construction category (CC1-CC4) for your project. Learn more about CC categories →

5. Shop Drawings Signed by Engineer

3D-modelled shop drawings signed off against the engineer's structural drawings, with connection detail annotations. This is what the fabricator actually cuts and welds from - and what the surveyor may cross-check.

6. Certificate of Compliance (at Sign-Off)

A single-page statement from the fabricator at project completion confirming the work meets AS 4100, AS/NZS 5131, and AS/NZS 1554.1. Your building surveyor asks for this to close the permit.

Working with A.C. Steel? All 6 items are standard on every project. Call 0431 885 854 or email info@acsteelconstruction.com.au to discuss your build.
AS 4100 is the standard. Compliance is the proof.
A.C. Steel provides mill certs, welder tickets, WPS, ITP, shop drawings, and Certificate of Compliance on every Melbourne project.
Call 0431 885 854 Email Us

AS 4100 in Melbourne Projects

Real A.C. Steel fabrication with the clause each detail satisfies. This is what compliant structural steel actually looks like on your site.

Cl. 5 · Beams

Residential Extension - Brighton

Steel beam over new open-plan living. UB section designed for bending capacity per AS 4100 Cl. 5, lateral restraint provided by ceiling framing above.

See residential structural steel →
Cl. 6 · Columns

Industrial Mezzanine - Keysborough

UC columns supporting mezzanine floor loads. Compression capacity per AS 4100 Cl. 6, effective length calculated with pinned base connection.

See industrial structural steel →
Cl. 9 · Connections

Commercial Frame - Footscray

Welded moment connections at beam-column junctions. AS 4100 Cl. 9 combined with AS/NZS 1554.1 SP-qualified welds - full traceability documented.

See commercial structural steel →

Browse our full Melbourne project portfolio →

AS 4100 in a Melbourne Building Permit

How AS 4100 compliance flows through a Victorian building permit - 5 checkpoints from design to sign-off, and the documents A.C. Steel supplies at each stage.

1

Design Stage

Your structural engineer produces drawings per AS 4100. A.C. Steel reviews and confirms constructability before quoting.

2

Building Permit Application

Engineer's drawings + structural certification submitted with building permit application to your Victorian building surveyor.

3

Fabrication + QA

A.C. Steel fabricates in Keysborough. Every weld inspected against WPS. Mill certs and welder tickets filed against each component.

4

Installation Inspection

Building surveyor may request site inspection of steel connections before subsequent trades cover the steelwork.

5

Certificate of Compliance

A.C. Steel supplies signed Certificate of Compliance confirming fabrication meets AS 4100 + AS/NZS 5131 + AS/NZS 1554.1 - the paperwork closing your permit.

Ready to start your permit workflow? Send drawings and we'll return a quote with the full compliance pack.
Email Drawings 0431 885 854

AS 4100 - Frequently Asked Questions

Answers to what Melbourne builders, architects, and building owners ask us most about AS 4100 compliance.

Is AS 4100 mandatory in Melbourne?
Yes - AS 4100 is referenced by the National Construction Code (NCC), which is the deemed-to-satisfy pathway for Australian building permits. If your Melbourne project uses structural steel, the building surveyor verifies compliance against AS 4100 (plus the sibling standards) before signing off. A structure that doesn't comply won't pass permit.
What's the difference between AS 4100 SP and GP welding?
SP (Structural Purpose) requires documented welder qualification and is the only acceptable category for load-bearing welds on beams, columns, connections. GP (General Purpose) is for non-structural applications only - handrails, decorative brackets, cover plates. A.C. Steel welds SP by default on every structural fabrication.
Do imported steel structures need to comply with AS 4100?
Yes. AS 4100 applies to the finished structure regardless of where components are fabricated. Imported PEB (pre-engineered building) systems must be verified against AS 4100 by an Australian engineer, and material grades must have traceable equivalents to AS/NZS 3679. Verify mill certificates, not just brand names.
How do I verify my fabricator is actually AS 4100 compliant?
Ask for the 6 items in our checklist above: mill certificates, welder qualification records, weld procedure specifications, inspection & test plan, signed shop drawings, and Certificate of Compliance. A compliant fabricator provides these as standard - not on request. If they don't have documented WPS or can't name welders on your job, that's a red flag. See our builder's guide to AS 4100 + AS/NZS 5131 for a deeper walkthrough.
What is the current edition of AS 4100?
The current edition is AS 4100:2020, which supersedes AS 4100:1998 (revised after 22 years). Updates include revised load combinations, improved connection design provisions, and alignment with the current AS/NZS 1170 loading standards. Always confirm your engineer is designing to :2020, not :1998.
Which construction category (CC) applies to my project?
Construction categories come from AS/NZS 5131. Most Melbourne residential extensions and small commercial builds fall under CC1 or CC2 (basic and standard QA respectively). Larger commercial (multi-storey, complex geometry) is CC3. CC4 is reserved for critical infrastructure (hospitals, transport). Your structural engineer nominates the category on your drawings. Full breakdown in our CC1-CC2-CC3 explained guide and AS/NZS 5131 Melbourne guide.
What steel grades meet AS 4100?
The standard structural grades are 300PLUS (Grade 300) and Grade 350 per AS/NZS 3679.1. Grade 300 (yield 300 MPa) covers most residential and commercial work. Grade 350 (yield 350 MPa) is used for higher-load applications or where lighter sections are preferred. Both are locally rolled by BlueScope and InfraBuild. See our residential steel beam span tables for typical member sizing.
Does A.C. Steel provide AS 4100 documentation on every project?
Yes - all 6 checklist items are standard on every A.C. Steel structural fabrication, not an upgrade. Mill certificates, welder qualifications, weld procedures, inspection records, signed shop drawings, and Certificate of Compliance are delivered as part of project handover. Your building surveyor gets the paperwork they need to sign off, no extra requests. Call 0431 885 854 or email us to discuss your project.

Start Your AS 4100 Compliant Project

Send us your drawings or call now for a written quote with full compliance documentation included as standard.

Call 0431 885 854 Email Our Team

Related Reading

More AC Steel guides on Australian structural steel standards, categories, and Melbourne project topics.

Standards Guide

AS 4100 Australian Structural Steel Standards Guide

Deeper dive on AS 4100 background, revisions, and safety implications for homes.
Builder Guide

AS 4100 + AS/NZS 5131 for Builders

Non-engineer walkthrough - what you need to verify a fabricator on your build.
Construction Categories

CC1, CC2, CC3 Explained

Which construction category applies to your project - and what QA it triggers.
Melbourne Focus

AS/NZS 5131 Construction Categories - Melbourne

Melbourne-specific breakdown of how CC1-CC4 translates to your project.
Beam Sizing

Residential Steel Beam Span Tables

Quick reference span tables for residential builders (verify with engineer).
Process

How Steel Fabrication Works

Behind the scenes at our Keysborough workshop - from CAD to install.

Full library: A.C. Steel blog →

Need AS 4100-Compliant Structural Steel in Melbourne?

Call, email, or send drawings. We supply the full compliance pack with every project.

Phone

0431 885 854
Mon-Fri 7am-5pm

Email

info@acsteelconstruction.com.au
Send drawings for AS 4100 quote

Workshop

43 Popes Rd, Keysborough VIC 3173
AS 4100 fabrication + install · Google Maps
A.C. Steel — Structural Steel Fabricators Melbourne logo

At A.C. Steel, we specialise in structural steel solutions tailored for residential, commercial, and industrial builds. We help builders and architects deliver structurally durable, cost-effective, and on-time projects.

 

Quick Link

Services

Contact

OPENING HOURS

  • Monday - Friday:
  • 7:00AM - 5:00PM

Get in Touch