AS 5113: Classification of External Walls Explained
AS 5113 classifies external wall assemblies based on their fire performance when tested at full scale. It is an assembly-level standard - it tests the complete wall system, not individual materials - and it sits in a different part of the compliance framework than the material-level tests most facade specifiers encounter daily.
This standard comes up regularly in specification discussions, particularly when fire engineers are involved. But what AS 5113 actually does, when it applies, and when it does not are questions worth addressing clearly. The distinction matters because it affects cost, programme, and which compliance pathway a project follows.
What is AS 5113?
AS 5113:2016, formally titled “Fire propagation testing and classification of external walls of buildings,” provides a framework for classifying external wall assemblies based on how they perform in a large-scale fire test. The standard was published by Standards Australia and draws on the established BS 8414 full-scale test methodology used internationally.
The key word is “assembly.” AS 5113 does not test a single material in isolation. It tests a representative section of an external wall - cladding, insulation, cavity, sarking, fixings, framing, and substrate - as a complete system. The test exposes that system to a severe fire and measures how the assembly responds.
This is fundamentally different from AS 1530.1, which tests a small cylindrical specimen of a single material in a furnace at 750 degrees Celsius. AS 1530.1 answers: is this material combustible? AS 5113 answers: how does this wall assembly behave when exposed to external fire?
Both standards have their place. They answer different questions, and understanding which one applies to a given project is essential for specifiers, fire engineers, and certifiers.
How does the full-scale fire test work?
AS 5113 does not define its own fire test method. Instead, it references the BS 8414 series for the test itself and provides the classification criteria for interpreting the results.
The test methods are:
- BS 8414-1 - for systems mounted on a masonry-backed substrate (representing concrete or blockwork structures)
- BS 8414-2 - for systems mounted on a steel-framed substrate (representing lightweight construction)
Both tests follow the same general principle. A representative wall assembly is constructed at full scale - typically a large L-shaped test rig approximately 8 metres tall with a return wing. A timber crib fire source is positioned at the base of the wall within a simulated window opening, producing a controlled but severe fire exposure.
The fire burns for approximately 30 minutes. During and after the fire, thermocouples embedded at specific heights within the wall assembly measure temperature. External observations record any flame spread, burning debris, and mechanical failure.
The measurements focus on three things:
Fire spread. Whether the fire propagates beyond the immediate area of the fire source. The classification criteria set specific temperature thresholds at defined heights above the fire source - essentially asking whether the fire climbed the wall or stayed contained.
Heat release. How much thermal energy the wall assembly contributes back to the fire. A wall system that adds fuel to the fire is more dangerous than one that absorbs heat passively.
Burning droplets and debris. Whether the wall system sheds flaming material as it is exposed to fire. Falling burning debris can ignite materials below the fire floor and create secondary fire spread pathways that are difficult to control.
Based on these measurements, AS 5113 assigns a classification to the wall assembly. The classification reflects the overall fire performance of the complete system - not any single component within it.
How is AS 5113 different from AS 1530.1?
This is the most common point of confusion, and it is worth being explicit.
| AS 1530.1 | AS 5113 | |
|---|---|---|
| Tests | Individual materials | Complete wall assemblies |
| Specimen | 45mm x 50mm cylinder | Full-scale wall rig (~8m tall) |
| Result | Binary: combustible or non-combustible | Classification based on fire spread, heat release, and burning debris |
| Heat source | Electric furnace at 750 degrees Celsius | Timber crib fire in simulated window opening |
| Purpose | Material-level gatekeeping | Assembly-level performance characterisation |
| Cost | Typically a few thousand dollars per material | $100,000 to $200,000 or more per assembly configuration |
| Timeline | Days to weeks | Months (including specimen construction, test scheduling, and reporting) |
AS 1530.1 is a material test. AS 5113 is a system test. A wall assembly can contain materials that individually pass AS 1530.1, yet the assembly could still be tested under AS 5113 if a fire engineer or certifier requires assembly-level evidence. Conversely, a wall containing some combustible components might achieve an acceptable AS 5113 classification if the assembly as a whole performs within the classification criteria.
The two standards operate at different levels of the compliance hierarchy, and neither replaces the other.
When does AS 5113 apply to a project?
This depends on which compliance pathway the project is following under the NCC.
Deemed-to-Satisfy (DtS) projects
Under the NCC’s Deemed-to-Satisfy provisions, external walls on Type A and B construction must be non-combustible. The relevant provision is C2D10, which lists specific materials - including aluminium and aluminium alloys - as deemed non-combustible, and requires all other materials to demonstrate non-combustibility through testing to AS 1530.1.
If every component in the external wall assembly satisfies the DtS non-combustibility requirements, there is generally no need for AS 5113 testing. The compliance pathway is satisfied at the material level. The project demonstrates compliance through material test certificates (AS 1530.1 reports from a NATA-accredited laboratory), not through full-scale assembly testing.
This is the straightforward scenario. Non-combustible cladding, non-combustible sarking, non-combustible insulation, steel or aluminium framing. Each component has a test certificate. The wall satisfies C2D10. No assembly-level fire test is required.
Performance Solution projects
AS 5113 becomes relevant when a project follows the Performance Solution pathway - typically because the wall assembly includes combustible components that prevent DtS compliance.
Common triggers include:
- Combustible insulation types in the cavity (certain PIR or phenolic foams that do not meet AS 1530.1 non-combustibility)
- Combustible membranes or sarking beyond the minor concessions allowed under DtS
- Composite cladding products with polymer cores
- Mixed-material facades combining non-combustible and combustible elements
In these situations, a fire engineer may reference AS 5113 classification as part of the evidence supporting the Performance Solution. The NCC’s Verification Method C1V3 specifically references AS 5113 as a means of assessing external wall fire performance. The fire engineer uses the AS 5113 classification - derived from a BS 8414 full-scale test - to demonstrate that the wall assembly meets the NCC’s Performance Requirements (CP1 through CP9) even though individual materials may not satisfy the DtS non-combustibility provisions.
This is where the cost and programme implications become significant. A full-scale BS 8414 fire test costs $100,000 to $200,000 or more, takes months to arrange (including specimen construction, test facility scheduling, and reporting), and the test data typically belongs to the party that commissioned it. If a product supplier has already conducted the test, their data may be available - but it applies only to the specific assembly configuration tested.
Where does AS 5113 sit in the standards framework?
The relationship between standards follows a logical hierarchy:
AS 1530.1 establishes whether individual materials are combustible. This is the foundation - the material-level gatekeeping test that underpins DtS compliance for external walls.
AS 5113 classifies how complete wall assemblies perform when exposed to fire. It builds on material-level data but tests the system as a whole - including interactions between components, cavity behaviour, and assembly-level fire spread.
NCC Performance Requirements (CP1-CP9) set the ultimate objectives: structural stability during fire, prevention of fire spread, safe evacuation. Both AS 1530.1 (via DtS) and AS 5113 (via Performance Solutions and Verification Method C1V3) feed into demonstrating that these requirements are met.
Each level addresses a different question. Material combustibility does not tell you how an assembly performs. Assembly performance does not tell you whether individual materials are combustible. The NCC requires both questions to be answered, but through different mechanisms depending on the compliance pathway chosen.
What does this mean for facade specification?
The practical implication is straightforward: material selection drives which standards you need to deal with.
If the external wall assembly uses non-combustible materials throughout - non-combustible cladding, non-combustible sarking, non-combustible insulation, steel or aluminium framing - the project can typically follow the DtS pathway. Compliance is demonstrated through AS 1530.1 material test certificates. AS 5113 assembly testing is not required.
Valmond & Gibson’s interloQ interlocking rainscreen system is tested as non-combustible to AS 1530.1 (CSIRO report FNC12595). element13 solid aluminium panels are tested as non-combustible to AS 1530.1 (CSIRO report FNC12545) with AS 1530.3 indices of Ignitability 0, Heat 0, Flame 0, Smoke 1 (CSIRO report FNE12552). In a DtS pathway with non-combustible materials throughout, these material-level certificates satisfy the NCC requirements without assembly-level testing.
If the wall assembly includes combustible components - perhaps specified by others on the project, such as certain insulation types or membranes - the conversation shifts to Performance Solutions and assembly-level evidence. That is where AS 5113 enters the picture, and where the fire engineer’s role becomes central.
V&G’s role in AS 5113 discussions
Valmond & Gibson supplies material-level compliance evidence: AS 1530.1 non-combustibility certificates, AS 1530.3 fire behaviour indices, weather performance data to AS/NZS 4284, and complete compliance documentation packs for interloQ and element13.
If a project requires AS 5113 classification - because the wall assembly includes combustible components or because the project is following a Performance Solution pathway - that assessment sits with the project’s fire engineer. We provide the material properties, test data, and system details they need as inputs to their analysis. We do not provide fire engineering services or AS 5113 classifications ourselves.
This is an important distinction. A facade supplier’s job is to provide accurate, well-documented material data. The fire engineer’s job is to assess how the complete assembly performs and whether it satisfies the NCC’s Performance Requirements. Both roles are necessary. Neither should try to do the other’s work.
The practical takeaway
For most projects using non-combustible facade materials, AS 5113 is a standard you should understand but may not need to engage with directly. The DtS pathway, supported by material-level AS 1530.1 testing, is simpler, faster, and less expensive.
Where AS 5113 does apply - mixed-material facades, Performance Solutions, or certifier requests for assembly-level evidence - it is a tool for fire engineers, not a requirement the specifier or supplier can resolve alone.
Understanding this distinction early in the design process avoids unnecessary cost, prevents programme delays, and keeps the compliance conversation focused on the right evidence for the right pathway.
Need compliance documentation for an upcoming facade project? Our team provides AS 1530.1 test certificates, compliance packs, and technical data to support your specification. Get in touch.
Related Reading
- AS1530.1 and AS1530.3: What Facade Fire Tests Actually Measure
- Performance Solutions vs Deemed-to-Satisfy
- Non-Combustible Cladding in Australia: NCC Compliance Guide
- Cavity Barriers in Facade Systems: When Does the NCC Require Them?
Last updated: 4 April 2026