A GRC fire submission usually fails on paperwork, not performance. The panel is cementitious and passes the furnace test; the report attached to the specification is for a different mix, a different thickness or a different coating. This is what AS 1530.1 and AS 1530.3 each measure, what the NCC does with each result, and the eight things worth checking before a test report goes into a submission.
It is written for architects, facade consultants and certifiers specifying glass reinforced concrete in Australia. If you are working to an overseas code, the fire standards atlas sets out the equivalent tests jurisdiction by jurisdiction.
First, the distinction that causes most of the trouble
Two different properties get called “fire rating” in the same sentence, and they are measured by different tests on different things.
Reaction to fire describes how a material behaves when fire reaches it: whether it ignites, how fast flame spreads across it, how much heat and smoke it releases. It is a property of the product, at the thickness and with the surface tested. AS 1530.1 and AS 1530.3 are both reaction-to-fire tests.
Fire resistance describes how long a complete wall, floor or door holds a fire back. It is a property of the assembly, measured under AS 1530.4 and expressed as a fire resistance level such as 90/90/90.
A non-combustible GRC panel has the best possible reaction to fire and no fire resistance rating at all. That is not a gap in the product. Cladding is not what carries the FRL; the wall behind it is. Asking a panel supplier for an FRL on a rainscreen panel is the single most common request that cannot be answered, and it usually means the specification has conflated the two.
AS 1530.1: does the material burn at all
AS 1530.1 is the furnace test that decides combustibility. A small cylindrical specimen, roughly 45 mm in diameter and 50 mm high, cut from the product as supplied, is placed in a vertical tube furnace held at about 750 °C. Thermocouples record the furnace temperature and the temperature at the centre and surface of the specimen, and an operator records any flaming. The run continues until temperatures stabilise, typically around 30 minutes.
The material fails if either the furnace or the specimen temperature rises more than 50 °C above the stabilised starting temperature, or if the specimen flames for more than five seconds. Several specimens are tested and all of them must pass. The result is reported as either Combustible or Not Deemed Combustible.
That second phrase is the one the code cares about. NCC Volume One clause C2D10 requires the external walls, and certain other elements, of Type A and Type B buildings to be non-combustible, and the NCC defines non-combustible as not deemed combustible under AS 1530.1. A product holding that result satisfies the requirement through the Deemed-to-Satisfy provisions with no further fire engineering. A product without it reaches those walls only through a Performance Solution, which in practice means an AS 5113 full-scale facade test and a fire engineer’s report.
The NCC also lists a handful of materials that may be used wherever non-combustibility is required without any test of their own: plasterboard, fibre-reinforced cement sheeting, pre-painted or coated steel, and bonded laminates meeting specified criteria. GRC is not on that list. Every GRC product used on a Type A or Type B external wall relies on its own AS 1530.1 report, which is why the report itself matters so much.
AS 1530.3: how the surface behaves in the first minutes
AS 1530.3 measures four early fire hazard properties at once and reports each as an index. A flat specimen, about 600 mm by 450 mm and tested with the surface and backing used in service, is mounted beside a gas fired radiant panel with a pilot flame above it, and the radiant heat is raised progressively.
| Index | Range | What it measures |
|---|---|---|
| Ignitability Index | 0 to 20 | Time to sustained ignition |
| Spread of Flame Index | 0 to 10 | Distance and rate of flame travel across the surface |
| Heat Evolved Index | 0 to 10 | Temperature rise in the exhaust |
| Smoke Developed Index | 0 to 10 | Light obscuration in the exhaust |
Lower is better in every case, so a result written as 0, 0, 0, 0 to 1 describes a material that did not ignite readily, did not carry flame, released little heat and produced almost no smoke. Several NCC concessions in C2D10 are written around a Spread of Flame Index of 0 and a Smoke Developed Index of not more than 3.
AS 1530.3 no longer does the job it once did for internal wall and ceiling linings. That work has moved to the group number under AS 5637.1, derived from a cone calorimeter or room test. AS 1530.3 is retained for specific applications and for several external wall concessions, which is why a GRC product intended for both facade and internal lining work may need results under both regimes.
Where AS 1530.4 and AS 5113 sit
Two further tests get quoted in facade packages and are not reaction-to-fire tests at all.
AS 1530.4 is the fire resistance test. A full-size element is placed in front of a furnace following a standard time-temperature curve and assessed for structural adequacy, integrity and insulation. The output is an FRL in minutes. It belongs to the whole assembly, including framing, lining, insulation, fixings and joints, and changing any of them voids it.
AS 5113 builds a section of the real external wall two or more storeys high and lights a fire at its base, assessing flame spread up the face and inside the cavity, burning debris and the damage afterwards. It is the test that supports a Performance Solution where a material cannot meet the Deemed-to-Satisfy route on its own.
A complete facade fire case will often reference all four: combustibility of the panel, indices or group number for the surface, an FRL for the wall behind, and in taller buildings a full-scale system test.
Eight things to check in the test report
The report is the deliverable. These are the checks worth making before it is attached to a submission.
- The product, not the family. The result applies to the specific mix tested. A polymer modified GRC is a different product to a standard cementitious GRC, and a report for one line does not cover another.
- Thickness and build. Sprayed, premix and single skin against monocoque behave differently. Confirm the tested build matches what is being specified.
- The surface as it will be installed. Coatings, sealers and applied finishes form part of the tested specimen. An untested coating applied over a tested substrate changes the product.
- Any backing or laminate. An insulated or laminated backing is part of the product for test purposes.
- The laboratory’s NATA accreditation for the test method being reported, not simply NATA accreditation in general.
- The standard and its edition, and whether that edition is the one referenced by the NCC version applying to the project.
- The wording of the result. “Not Deemed Combustible” is the phrase the NCC recognises. “Non-combustible”, “fire rated” and “fire resistant” written in marketing material are not test results.
- Date and traceability. A report should be current, name the client and the sampled product, and be reproducible in full rather than as an extract.
What this means for GRC specifically
GRC with a cementitious matrix is, as a class, capable of passing AS 1530.1, alongside fibre cement, terracotta, natural stone, glass and solid metal sheet. Polymer composites including FRP, aluminium composite panels with a polyethylene core, and timber and timber composites cannot pass the furnace test and are classified by other means.
“Capable of passing” is not the same as “has passed”. The matrix chemistry, admixtures, any polymer content and any applied coating all bear on the outcome, which is why the NCC does not deem GRC non-combustible as a class and why the product-specific report is the document that matters.
For ShapeShell™-RC, the independent results are:
| Test standard | Testing body | Result |
|---|---|---|
| AS/NZS 1530.1 combustibility | Ignis Labs Pty Ltd | Not Deemed Combustible |
| AS/NZS 3837 heat and smoke release rates | AWTA Product Testing | Non-ignitable / flame-resistant |
Full reports are issued on request for a nominated project and product configuration. Where a project needs an index set under AS 1530.3 or a group number under AS 5637.1 for an internal lining application, ask before the specification is issued rather than at shop drawing stage.
Three mistakes that cost programme time
Specifying an FRL for a rainscreen panel. The panel cannot carry one. Put the FRL on the wall behind it and specify reaction to fire for the cladding.
Assuming a result travels between jurisdictions. An AS 1530.1 result is not an EN ISO 1182 result and is not an ASTM E136 pass. A product sold in several markets needs the test each market’s code references. The fire standards atlas compares those regimes side by side.
Treating the material result as a system approval. Compliance is assessed on the complete wall: backing wall, structural supports, insulation, cavity treatment, cavity barriers, fixings, sealants and coatings. A non-combustible panel is a necessary part of that case and not the whole of it. Our fire performance page sets out the full test position, and panel weights that feed the substructure case can be checked with the panel weight and crane calculator.
Frequently asked questions
Is GRC non-combustible?
GRC with a cementitious matrix is capable of passing AS 1530.1, and where a specific product holds a Not Deemed Combustible result it is non-combustible for NCC purposes. GRC is not on the NCC’s list of materials deemed non-combustible without a test, so the product-specific report is required.
What is the difference between AS 1530.1 and AS 1530.3?
AS 1530.1 is a pass or fail furnace test that decides whether a material is combustible at all. AS 1530.3 assumes the material can burn and grades how it behaves in the first minutes of radiant heat exposure, reporting four indices for ignitability, spread of flame, heat evolved and smoke developed.
Does a GRC panel have a fire resistance level?
No. A fire resistance level belongs to a complete wall, floor or door assembly tested under AS 1530.4. Cladding panels are assessed for reaction to fire and, on taller buildings, as part of a full-scale facade test under AS 5113.
Does a coating change the AS 1530.1 result?
It can. The result applies to the specimen as tested, including any surface coating or backing. A coating applied after testing, or a different coating to the one tested, puts the product outside the scope of the report.
Can an overseas fire test report be used on an Australian project?
Not directly. The NCC references AS 1530.1 for non-combustibility, and an EN ISO 1182 or ASTM E136 result does not substitute for it. The reverse also holds, which is why products sold across several markets hold several reports.
Which test does the NCC require for internal wall and ceiling linings?
Group number under AS 5637.1 has taken over that role from AS 1530.3 for most lining applications. AS 1530.3 is retained for specific applications and for several external wall concessions in C2D10.
