Fibre Reinforced Facade Encyclopedia: Testing and standards
The cone calorimeter is a bench scale reaction-to-fire test in which a 100 millimetre square specimen is exposed to a controlled radiant heat flux from a conical electric heater, ignited by a spark, and burned while instruments measure the heat it releases, the mass it loses and the smoke it produces. In Australia the method is AS/NZS 3837; internationally it is ISO 5660-1 and ASTM E1354. It is the workhorse of reaction-to-fire testing, and in the National Construction Code its main role is to predict a group number under AS 5637.1 without running a full room fire.
A specimen the size of a coaster produces enough data to predict how a full 3.6 by 2.4 by 2.4 metre room lined with the same material will behave. That prediction is what AS 5637.1 allows in place of an AS ISO 9705 room test, and it is why most cladding and lining products are cone tested rather than room tested.
At a glance
| Property | Typical value | Note |
|---|---|---|
| Standards | AS/NZS 3837; ISO 5660-1; ASTM E1354 | Same apparatus, minor procedural differences |
| Specimen | 100 by 100 mm, up to 50 mm thick | Tested with its real substrate and finish |
| Orientation | Normally horizontal, face up | Vertical orientation permitted for some products |
| Irradiance | Commonly 50 kW/m²; 25 and 35 kW/m² also used | 50 kW/m² is the level used for group number prediction |
| Ignition | 10 kV spark igniter above the specimen | Piloted ignition |
| Duration | Typically until 2 minutes after flame out | Commonly 10 to 20 minutes |
| Heat release principle | Oxygen consumption, about 13.1 MJ per kg of oxygen | Measured in the exhaust duct |
| Main outputs | Time to ignition (s), peak and average HRR (kW/m²), total heat release (MJ/m²), mass loss rate, smoke | Plus effective heat of combustion |
| Replicates | Normally three specimens | Repeatability checked between them |
| Family | Reaction to fire | Not a fire resistance test and not a non-combustibility test |
How the test runs
The specimen is wrapped in foil on its back and edges, placed in a holder on a load cell, and positioned 25 millimetres below a conical heating element calibrated to the chosen irradiance. The heater delivers a uniform radiant flux over the exposed face, simulating the radiation a surface receives from a developing fire rather than direct flame contact. A spark igniter sits above the face so that any flammable gases released are ignited as soon as they reach an ignitable concentration.
The operator records the time to sustained ignition. From that point the specimen burns under the hood while the exhaust duct instrumentation measures flow, oxygen, carbon dioxide and carbon monoxide, and a laser photometer measures smoke obscuration. The load cell records mass continuously. The test ends a set period after flaming stops, and the whole sequence is repeated on further specimens.
The result is a curve rather than a number, and the shape of the curve carries the meaning. A thin combustible skin over a non-combustible backing gives a sharp early peak that collapses; a thick homogeneous polymer gives a broad sustained plateau. Both can share the same peak value and behave very differently in a room.
What it measures
- Time to ignition, in seconds, at the stated irradiance
- Heat release rate, in kW/m², reported as the peak and as averages over the first 60, 180 and 300 seconds after ignition
- Total heat release, in MJ/m², the area under the curve
- Effective heat of combustion, in MJ/kg, computed from heat release and mass loss
- Mass loss rate, in g/s per square metre
- Specific extinction area, in m²/kg, the standard smoke measure from this apparatus
Every one of these belongs to the specimen as tested, at that thickness, with that substrate, that surface finish and that irradiance. A gel coated laminate tested at 50 kW/m² tells you very little about the same laminate with a different gel coat, and nothing at all about a different thickness.
Predicting a group number
AS 5637.1 allows a group number to be determined either by a full room test to AS ISO 9705 or by calculation from cone calorimeter data obtained under AS/NZS 3837 at 50 kW/m². The prediction model uses the time to ignition and the averaged heat release rates to estimate when the lining would drive a room to flashover, taken as one megawatt of total heat release, under the AS ISO 9705 burner sequence of 100 kW for ten minutes then 300 kW for ten more.
Group 1 is predicted where flashover would not occur within twenty minutes, Group 2 between ten and twenty minutes, Group 3 between two and ten minutes and Group 4 within two minutes. The prediction route is cheaper and faster than building a room, which is why nearly every commercial group number classification is obtained this way. ShapeShell-RT holds an AS 5637 Group 1 classification from AWTA Product Testing.
What the cone calorimeter cannot tell you
It is a reaction-to-fire test on a material. It is not a combustibility test: a material cannot be declared non-combustible from cone data, because non-combustibility is decided by a furnace test under AS 1530.1, EN ISO 1182 or ASTM E136. It is not a fire resistance test either: no cone result contributes to a fire resistance level under AS 1530.4 or EN 13501-2.
Its scale is also its limitation. A 100 millimetre specimen has no joints, no fixings, no cavity behind it, no edges exposed to flame and no adjacent panels to radiate to. It cannot reproduce delamination at a fastener, flame running up a cavity, or a substrate softening and dropping the panel. Those are precisely the mechanisms that drove the facade fires of the last fifteen years, and they are why codes require a full-scale test such as AS 5113, BS 8414 or NFPA 285 for tall buildings rather than accepting bench data.
For the ShapeShift systems the division is clean. ShapeShell-RC is a cementitious system and is Not Deemed Combustible under AS/NZS 1530.1, tested by Ignis Labs, so heat release is not the question for it. ShapeShell-RT is a fibre reinforced polymer system; it is combustible, it cannot pass AS 1530.1, EN ISO 1182 or ASTM E136, and its Group 1 classification and its EN 13501-1 class of B-s2,d0 from Intertek Testing Services are the heat release derived results that describe it. Its full-scale evidence is the BS 8414 and AS 5113 test at BRE Global.
Standards and references
- AS/NZS 3837 Method of test for heat and smoke release rates for materials and products using an oxygen consumption calorimeter
- ISO 5660-1 Reaction to fire tests: heat release, smoke production and mass loss rate (cone calorimeter method)
- ASTM E1354 Standard Test Method for Heat and Visible Smoke Release Rates for Materials and Products Using an Oxygen Consumption Calorimeter
- AS 5637.1:2015 Determination of fire hazard properties: wall and ceiling linings (group number prediction route)
- AS ISO 9705 Fire tests: full-scale room test for surface products (the reference test)
- NCC 2022 Volume One Specification 7 (fire hazard properties)
Related terms
Questions specifiers ask
What does the cone calorimeter measure?
Heat release rate, total heat release, time to ignition, mass loss rate and smoke production from a 100 millimetre square specimen exposed to a set radiant heat flux, usually 50 kW/m².
Can a group number be obtained from cone calorimeter data?
Yes. AS 5637.1 allows a group number to be predicted from AS/NZS 3837 data at 50 kW/m² instead of running a full AS ISO 9705 room test. It is the usual commercial route.
Is the cone calorimeter a non-combustibility test?
No. Non-combustibility is decided by a furnace test: AS 1530.1 in Australia, EN ISO 1182 in Europe and ASTM E136 in the United States. Cone data cannot produce or substitute for that result.
Why is 50 kW/m² used?
It represents the radiant flux a surface receives from a well developed fire in a compartment, and it is the irradiance the AS 5637.1 group number prediction model is calibrated against.
Does a good cone result mean a facade will pass a full-scale test?
No. Bench scale data has no joints, no cavity, no fixings and no edge exposure. It is a useful predictor for linings and a poor predictor for facade systems, which is why AS 5113, BS 8414 and NFPA 285 exist.
ShapeShell-RT holds an AS 5637 Group 1 classification from AWTA Product Testing and a full-scale AS 5113 pass from BRE Global. See the results in one table. See ShapeShell fire test data
Reviewed by Richard Halvorsen, General Manager, ShapeShift Technologies. Last updated September 2026.