Colorbond Metal Safety Signs — Australian Standards & Substrate Specs
Colorbond isn't a single standard — three separate Australian Standards apply to a genuine Colorbond steel sign. Here's what each covers, why the third one (AS/NZS 2728) is the one most suppliers forget to cite, and how substrate choice should change with the install location.
Last reviewed:
The three standards that apply
A Colorbond metal sign has three distinct specification layers — base steel, dimensional tolerance, and paint system. Each has its own Australian Standard. A complete specification cites all three. If you only see AS 1397 on a supplier’s spec sheet, the product standard for the paint system is missing.
Base steel substrate
Continuous hot-dip metallic-coated steel sheet and strip. Covers the zinc or zinc/aluminium coating applied to the raw steel coil during manufacture, before any paint layer. This is the corrosion-protection base of every Colorbond sign. Coating masses are designated by codes such as Z275 (zinc) or AZ150 (Zincalume aluminium/zinc alloy).
Dimensional tolerances
Tolerances for flat-rolled steel products. Sets allowable variation on sheet thickness, width, length and flatness. Relevant because a Colorbond sign specified at 0.55mm BMT needs thickness tolerance tight enough for folded-edge and pre-drilled-hole accuracy to remain consistent across a batch.
Prefinished / metallic-coated steel (the paint system)
Prefinished/prepainted sheet metal products for interior/exterior building applications. This is the product standard BlueScope’s Colorbond steel is manufactured to. It classifies paint systems by durability category (Category 1–4) and defines the test regime for gloss retention, colour fade, chalking, and corrosion resistance of the painted finish. Any spec sheet that omits AS/NZS 2728 is leaving out the standard that actually covers the Colorbond paint film.
Why the AS/NZS 2728 omission matters
A number of Australian signage suppliers cite AS/NZS 1365 and AS 1397 in their Colorbond product descriptions but omit AS/NZS 2728. On the surface this looks like an administrative detail, but it matters for two reasons. First, it indicates the supplier may not actually be using genuine BlueScope Colorbond sheet — AS/NZS 2728 is the product standard, and authentic Colorbond is manufactured and tested against it. Second, a procurement officer or facilities manager reviewing substrate specs against a tender requirement needs the full standards list to confirm compliance.
Our specification sheets cite all three standards. If you’re comparing a quote from us against another supplier, check what they have referenced. The absence of AS/NZS 2728 is worth asking about.
When to use Colorbond, when to use aluminium
| Install context | Recommended substrate | Why |
|---|---|---|
| Warehouse/factory wall-mount | 0.55mm Colorbond | Rigid, clean face, 10+yr indoor life |
| Construction site / temporary | 5mm corflute or 3mm polypropylene | Cheap, lightweight, not intended to last |
| Fence-mount (long-term outdoor) | 0.55mm Colorbond or 4mm ACM | Both handle UV, ACM is more impact-tolerant |
| Pole-mounted roadway / traffic | 1.4mm aluminium to AS 1743 | No rust exposure if edges get nicked |
| Marine / coastal exposure | Aluminium or stainless | Steel (even Colorbond) red-rusts at cut edges |
| High-impact / vandalism risk | 3mm ACM or 3mm aluminium | More rigid than 0.55mm steel, easier to replace |
Typical Colorbond sign construction
- Substrate: Genuine BlueScope Colorbond steel, 0.42mm or 0.55mm BMT, zinc or zinc/aluminium base coating to AS 1397, paint system to AS/NZS 2728.
- Graphics: 7-year or 10-year polymeric cast vinyl face-applied, or UV digital print direct-to-substrate with matched ICC profile.
- Lamination: Optional 7yr UV-stable laminate for additional fade and scratch protection on vinyl-face signs.
- Edges:Square-cut and de-burred as standard. Radius corners available; drilled mounting holes (typically Ø6mm) in standard corner positions.
- Fixings: Stainless-steel tek screws or M6 bolts for fence / wall-mount; not supplied by default — quote separately.
Standard sizes and pricing bands
Our Colorbond safety signs follow Australian convention on standard formats: 450×300mm, 600×450mm, 900×600mm. Volume breaks apply at quantities of 5, 10, 25, 50 and 100+. Custom sizes are cut from coil to your specification with no tooling charge. Large-run orders (500+ units of a single design) ship from nested production on the CNC for optimal substrate yield.
Official references
- Standards Australia — AS 1397 (metallic-coated steel sheet and strip)
- Standards Australia — AS/NZS 1365 (dimensional tolerances)
- Standards Australia — AS/NZS 2728 (prefinished/metallic-coated steel products)
- BlueScope Steel — Colorbond product information
Frequently asked questions
Is Colorbond a material or a brand?
Both. Colorbond is BlueScope's registered trade name for a specific family of pre-painted zinc/aluminium-coated steel sheet manufactured in Australia. The underlying substrate is hot-dip metallic-coated steel to AS 1397, with a proprietary paint system applied to BlueScope's product specification and the AS/NZS 2728 prefinished-steel standard. When a sign is described as 'Colorbond', it should be produced from genuine BlueScope-manufactured sheet — not a generic pre-painted substitute.
Which Australian Standards apply to a Colorbond metal sign?
Three standards commonly apply: AS 1397 covers the base steel (continuous hot-dip metallic-coated, incl. zinc and zinc/aluminium coatings); AS/NZS 1365 covers dimensional tolerances on sheet and strip; and AS/NZS 2728 covers the prefinished / metallic-coated steel product — this is the standard BlueScope's Colorbond steel is manufactured to. Citing only AS 1397 and AS/NZS 1365 (which some competitors do) omits the actual product standard for the paint system. All three should appear on the specification.
What thickness Colorbond is used for safety signs?
Most workplace and traffic safety signs use 0.42mm or 0.55mm BMT (base metal thickness) Colorbond. 0.42mm is the standard thickness for warning, prohibition and mandatory signs up to 600×450mm. 0.55mm is used for larger formats (900×600mm and above) or where additional rigidity is required for pole-mounted or exterior wall-mounted installations. For roadwork and RAV signage, 1.4mm aluminium is more common than Colorbond due to the retroreflective specification.
How long does a Colorbond sign last outdoors?
BlueScope warranties for Colorbond roofing sheet (a related but more demanding application) run 10–25 years depending on environment and colour range. For signage applications, realistic outdoor life is 10–15 years before visible fade in the UV-exposed face — longer in coastal-protected environments, shorter in marine or severe industrial exposure. The signage face typically fails before the substrate: the vinyl or ink layer fades, but the underlying Colorbond sheet itself remains sound.
Is Colorbond better than aluminium for safety signs?
Different purposes. Colorbond (steel) gives a premium pre-painted face, is rigid, and is the natural choice for wall-mount and fence-mount signage that needs to look sharp for a long service life. Aluminium (1.4mm–3mm) is preferred for pole-mounted roadway, construction and traffic signage because it won't rust if the paint system is damaged. For most workplace signs (warehouse, factory, building site interior), Colorbond is the right call; for retroreflective roadway signs exposed to impact, use 1.4mm aluminium to AS 1743 with Class 1W sheeting to AS/NZS 1906.1.
Browse Colorbond safety signs
All our Colorbond signage is made from genuine BlueScope sheet to AS 1397, AS/NZS 1365 and AS/NZS 2728. Volume pricing to 40% off at high quantities, delivered Australia-wide on orders over $250.
Planning signage for a specific site? These interactive checklists bring together the sign families covered above alongside the rest of what the workplace typically needs.