Non-combustible and fire retardant are not the same thing. They sound related, they appear in similar contexts, and they are regularly used interchangeably in project conversations. But in the National Construction Code, they refer to different test standards, measure different properties, and carry different compliance implications. Confusing the two can lead to specification errors, certification delays, and products being submitted for approval that do not actually meet the requirement.
This article explains the distinction, why it matters, and what the NCC actually requires for external wall cladding.
What does non-combustible mean under the NCC?
Non-combustible, as defined by the NCC, means a material that does not contribute to fire when tested to AS 1530.1:1994. This is a binary classification. The material either passes and is classified as non-combustible, or it does not pass and is classified as combustible. There is no middle ground, no partial credit, and no grading scale.
The test itself is severe but simple. Small cylindrical specimens are placed in an electric tube furnace at 750 degrees Celsius for 30 minutes. The test measures three things: whether the specimen causes the furnace temperature to rise by more than 50 degrees, whether it loses more than 50 percent of its mass, and whether it produces sustained flaming for more than 5 seconds. If any specimen fails on any criterion, the material is combustible.
Materials like solid aluminium, steel, concrete, and glass pass AS 1530.1 comfortably. Materials with organic content — timber, most plastics, and composite panels with polymer cores — do not.
What does fire retardant mean?
Fire retardant is not a defined classification under the NCC in the way that non-combustible is. The term is used loosely in the industry to describe materials that resist ignition, slow flame spread, or limit heat release — but these are behavioural characteristics, not a binary classification.
The standard most closely associated with fire retardant behaviour is AS 1530.3:1999, which tests a material’s ignitability, flame propagation, heat release, and smoke development. Unlike AS 1530.1, AS 1530.3 does not produce a pass/fail result. It produces four numerical indices, each scored from 0 to 20, with lower scores indicating better performance.
The NCC uses AS 1530.3 results to assign group numbers to wall and ceiling lining materials. Group 1 materials have the best fire performance characteristics (lowest indices) and can be used in the most restrictive locations — fire-isolated exits, for example. Group 2 and Group 3 materials have progressively less restrictive requirements on where they can be installed.
A material described as “fire retardant” might have low AS 1530.3 indices — slow to ignite, limited flame spread, minimal heat and smoke. But that does not make it non-combustible. It can still fail AS 1530.1 entirely.
Why do specifiers confuse the two?
The confusion typically arises because both terms relate to fire performance and both involve Australian Standards with similar numbering. In conversation, “fire rated,” “fire resistant,” “fire retardant,” and “non-combustible” are often treated as interchangeable descriptions of a product that performs well in fire. In practice, each term has a specific technical meaning, and only one of them — non-combustible — is the binary classification the NCC uses for external wall cladding on Type A and B construction.
Product marketing contributes to this. A product described as “fire retardant” or “fire resistant” may lead a specifier to believe it satisfies the non-combustibility requirement for external walls. It may not. A product with excellent AS 1530.3 indices — Ignitability 0, Flame 0, Heat 0, Smoke 1 — can still be combustible if it has any organic content that causes it to fail the AS 1530.1 criteria.
The reverse assumption also causes problems. Some specifiers assume that because a material is non-combustible, it automatically has favourable AS 1530.3 results. While this is generally true for solid metals and masonry, it is not a guarantee for all non-combustible materials, and having the actual test data removes the assumption from the equation entirely.
What does the NCC require for external walls?
For external wall cladding on Type A and B construction — which covers most multi-storey commercial and residential buildings — the Deemed-to-Satisfy provisions under C2D10 require materials to be non-combustible. This means AS 1530.1 is the relevant test, not AS 1530.3.
C2D10(5) lists certain materials that are deemed non-combustible without testing: concrete, terracotta, stone, ceramics, and metals commonly used in building. For products not on this list, or where the certifier requires documented evidence, an AS 1530.1 test report from a NATA-accredited laboratory is needed.
AS 1530.3 becomes relevant for internal wall and ceiling linings, where the NCC uses group numbers to determine which materials can be used in which building locations. It is also relevant where a fire engineer is preparing a Performance Solution and wants to characterise a material’s fire behaviour beyond the binary combustible/non-combustible classification.
For external facades on multi-storey buildings, though, the question is simple: is the material non-combustible to AS 1530.1? If yes, the DTS pathway is available. If no, a Performance Solution is required, which means fire engineering input, additional analysis, and typically more time and cost.
How does this affect product selection?
The practical implication is that when selecting facade cladding for a building where C2D10 applies, the first question is AS 1530.1 compliance. Everything else — aesthetics, cost, lead time, installation method — sits behind this threshold requirement. A product that is not non-combustible will require a Performance Solution to be used on the facade, and that changes the project’s cost, program, and risk profile.
Choosing a non-combustible facade product from the outset avoids this entirely. Solid aluminium and extruded aluminium products are non-combustible by nature. The compliance documentation confirms what the material inherently is, rather than trying to demonstrate that a combustible material can be used safely through additional analysis.
Where a specifier wants a complete fire performance picture, having both AS 1530.1 and AS 1530.3 results provides the most robust documentation package. The AS 1530.1 report confirms non-combustibility for the C2D10 requirement. The AS 1530.3 report characterises the material’s fire behaviour in detail, which can support fire engineering assessments and provide additional confidence for certifiers.
Where do V&G products sit?
Valmond & Gibson’s interloQ interlocking rainscreen panels are tested as non-combustible to AS 1530.1 (CSIRO report FNC12595). The element13 solid aluminium panels are tested as non-combustible to AS 1530.1 (CSIRO report FNC12545) and carry AS 1530.3 results of Ignitability 0, Flame 0, Heat 0, Smoke 1 (CSIRO report FNE12552).
Both products satisfy the C2D10 non-combustibility requirement through the DTS pathway. The element13 AS 1530.3 results are among the lowest achievable for a solid material, providing a complete fire performance profile for specifiers and certifiers who want both tests documented.
All reports are from CSIRO, a NATA-accredited laboratory (accreditation number 165). Report numbers are available for direct citation in specifications and compliance statements.
Need fire test documentation for a facade specification? Talk to our team for compliance packs and test report references.
Related Reading
- AS1530.1 and AS1530.3: What Facade Fire Tests Actually Measure
- AS1530.1 Explained: Non-Combustible Cladding in Australia
- Performance Solutions vs Deemed-to-Satisfy
- Solid Aluminium vs Composite Panels
Last updated: 4 April 2026