Fibre Reinforced Facade Encyclopedia: Testing and standards
Combustible cladding is any external wall material that ignites and burns when it is tested for combustibility, which in Australia means a result of Combustible under AS 1530.1. The category is wide. It covers aluminium composite panels with a polyethylene core, expanded and extruded polystyrene, polyurethane, polyisocyanurate and phenolic foam insulation, timber and timber composites, most membranes and coatings, and every polymer composite including fibre reinforced polymer (FRP). Combustible is a test result, not a verdict on whether a product may be built with. What it decides is which compliance pathway the product has to take.
Combustible is not a synonym for unsafe, and non-combustible is not a synonym for compliant. The furnace test sorts materials into two boxes. What matters after that is which box the National Construction Code lets you build with, on which buildings, and on what conditions.
At a glance
| Property | Typical value | Note |
|---|---|---|
| Australian test | AS 1530.1 furnace at about 750 °C | Reported as Combustible or Not Deemed Combustible |
| European equivalent | EN 13501-1 Classes B to F | A1 and A2 are the non-combustible and limited combustibility end |
| US equivalent | Fails ASTM E136; graded by ASTM E84 Class A, B or C | Flame Spread Index 0 to 200 |
| Materials in the category | ACP with polyethylene core, foam insulation, timber, FRP, membranes, most coatings | Always product specific |
| NCC status | Outside the Deemed-to-Satisfy route for external walls of Type A and Type B buildings | C2D10 |
| Compliance route | Performance Solution supported by an AS 5113 full-scale test | Verification Method C1V3 |
| Full-scale rig | At least 8 m of wall exposed to a 30 minute timber crib fire of about 3 MW | AS 5113 and BS 8414 |
| Australian audits | State rectification programs running from 2017 onward | Coverage and deadlines vary by state |
Which materials are combustible
- Aluminium composite panel with an unmodified polyethylene core, and mineral filled cores below the filler content that passes a furnace test
- Expanded polystyrene, extruded polystyrene, polyurethane, polyisocyanurate and phenolic insulation, including render systems built over them
- Timber, engineered timber, bamboo and wood plastic composites
- Fibre reinforced polymer, solid surface materials, high pressure laminates and most plastics
- Bituminous and polymer sarkings, breather membranes, sealants and thick applied coatings
Every entry on that list is a generic material family, and combustibility is a property of the specific product at the specific thickness tested. A mineral filled composite core, a fire retardant treated timber and a fire retardant FRP laminate can all behave very differently from the untreated version of the same material, but none of them becomes non-combustible by being treated. Non-combustibility is decided only by the furnace test described on the non-combustibility page.
What the National Construction Code does with the result
Under clause C2D10 of NCC 2022 Volume One (check the edition adopted in your jurisdiction), external walls and their attachments in buildings of Type A and Type B construction must be non-combustible. A product reported as Combustible under AS 1530.1 cannot satisfy that clause directly, so the Deemed-to-Satisfy route is closed to it. The Code does allow several narrow concessions within C2D10 for ancillary elements, thin finishes, sarking and bonded laminates meeting specified criteria, and those concessions are set out in full on the NCC external walls page.
Where a designer wants a combustible cladding on a building that falls under C2D10, the remaining route is a Performance Solution. Verification Method C1V3 sets out the conditions, the central one being an AS 5113 classification for the external wall system as it will be built, supported by a fire engineer’s assessment of the building as a whole. The test result is necessary evidence; it is not compliance on its own.
The Australian rectification context
Two fires changed the regulatory position. A 2014 apartment building fire in the Melbourne Docklands and the 2017 Grenfell Tower fire in London both showed fire spreading rapidly up the outside of a building through the cladding system rather than through the compartment walls. Following these, the Building Ministers’ Forum commissioned the Shergold and Weir report into building compliance, and every Australian state and territory set up a cladding audit or rectification program. Victoria, New South Wales and Queensland each established a structured process for identifying buildings with combustible external cladding, assessing risk and funding or requiring remediation.
The audits concentrated on two system types: aluminium composite panels with polyethylene cores, and rendered expanded polystyrene systems. Both are combustible under AS 1530.1, and in the configurations examined neither was supported by a full-scale facade test. The point of interest for a specifier is not the identity of any particular building or supplier but the mechanism the audits exposed. Risk sat in the system, not in a single certificate, and documentation that recorded only a material property was not enough to demonstrate how the assembled wall would behave.
Combustible is a category, not a level of risk
Treating every combustible product as equivalent is as unhelpful as treating none of them as a concern. A polyethylene cored composite panel has a very high calorific value, melts and drips, and carries flame vertically inside a cavity. A fire retardant FRP laminate with a mineral filled resin system behaves differently under the same fire, which is why reaction-to-fire classifications such as group number, EN 13501-1 class and ASTM E84 flame spread exist to grade the materials that cannot pass a furnace test.
That grading still does not answer the question a certifier asks about an external wall, which is what the assembled system does. Only a full-scale test answers that, which is why the codes added AS 5113, BS 8414 with BR 135 and NFPA 285.
Where FRP and ShapeShell-RT sit
FRP is a polymer composite with a thermoset resin matrix. It is combustible and it is not non-combustible, and no resin system, filler or coating changes that. ShapeShell-RT is an FRP system, so the same applies to it: it does not hold and cannot hold an AS 1530.1 Not Deemed Combustible result.
The pathway it uses instead is the reaction-to-fire and full-scale test pathway. ShapeShell-RT holds an AS 5637 Group 1 classification from AWTA Product Testing and an EN 13501-1 classification of B-s2 from Intertek, and it has been tested to BS 8414 and AS 5113 at BRE Global, meeting all AS 5113 criteria. On an Australian project that combination is the evidence base for a C1V3 Performance Solution. Where the client requires the Deemed-to-Satisfy route instead, the answer is a non-combustible material, and ShapeShell-RC, a glass fibre reinforced concrete system with an AS/NZS 1530.1 result of Not Deemed Combustible from Ignis Labs, is the system for that case.
Standards and references
- AS 1530.1-1994 Combustibility test for materials
- NCC 2022 Volume One C2D10 (non-combustible building elements), Schedule 1 definition of non-combustible, C1V3 (external walls verification method)
- AS 5113:2016 Classification of external walls of buildings based on reaction-to-fire performance
- AS 5637.1:2015 Determination of fire hazard properties, wall and ceiling linings
- EN 13501-1 (reaction to fire classification, Europe and UK); BS 8414 with BR 135
- ASTM E136 (combustibility) and ASTM E84 (surface burning characteristics), United States
- Building Confidence: Improving the effectiveness of compliance and enforcement systems (Shergold and Weir, 2018)
Related terms
Questions specifiers ask
Is combustible cladding banned in Australia?
No. The National Construction Code closes the Deemed-to-Satisfy route for external walls of Type A and Type B buildings to combustible materials, and leaves a Performance Solution route through Verification Method C1V3 and an AS 5113 full-scale test. Individual states have added their own restrictions on particular products, so check the current state position.
Is FRP combustible?
Yes. FRP has a thermoset polymer matrix and cannot pass a combustibility furnace test. Fire retardant resin systems improve its reaction-to-fire classification but do not make it non-combustible. ShapeShell-RT is an FRP system and complies through AS 5637 Group 1, EN 13501-1 B-s2 (Intertek) and a BS 8414 and AS 5113 test at BRE Global rather than through non-combustibility.
How do I tell if existing cladding is combustible?
Identify the product and obtain its test report. For composite panels the core material and its filler content decide the result, and the only reliable evidence is an AS 1530.1 report or an equivalent furnace test for the exact product. Visual inspection alone cannot distinguish a polyethylene core from a mineral filled one.
Does a Group 1 classification make a combustible cladding acceptable on an external wall?
Not by itself. Group number is a reaction-to-fire classification for wall and ceiling linings. For an external wall in Type A or B construction the Code requires either non-combustibility or a Performance Solution supported by AS 5113.
What replaces combustible cladding in a rectification project?
Either a non-combustible material that satisfies AS 1530.1 directly, or a system with an AS 5113 classification used under a Performance Solution. Weight matters in recladding because the existing structure and fixings were designed for the original panel, which is where lightweight systems are usually considered.
Reviewing cladding on a live or existing project? ShapeShell-RC is non-combustible to AS/NZS 1530.1, and ShapeShell-RT passed all AS 5113 criteria at BRE Global. See ShapeShell fire test data
Reviewed by Richard Halvorsen, General Manager, ShapeShift Technologies. Last updated September 2026.