Timber is loved for it’s ambient and design sensibilities, however knowing it’s fire performance is key to keeping yourspace safe and compliant

Timber is one of the most coveted materials in contemporary interiors, loved for its natural warmth, touchable texture, and connection to nature. But when it comes to fire, timber often gets a bad rap, or is skipped altogether, thanks to outdated or incorrect assumptions.

The good news? In Australia, timber linings and claddings can be specified once their fire performance is properly tested and documented.

“Timber is a beautiful, natural material that shouldn’t be ruled out just because of fire myths,” says Matthew Felton, CEO of Glosswood. “When specified correctly, timber can meet high fire-performance standards while keeping all its warmth, texture, and style.”

Understanding Group Numbers

A Group Number is a fire-performance classification used in the NCC that indicates how a wall or ceiling lining behaves in a fire, considering ignition, heat release, and smoke generation.

• Group 1: Highest performance; resists fire spread, limits heat and smoke. Required in corridors, exits, healthcare, aged care, and many multi-residential spaces.
• Group 2: Acceptable for a wide range of commercial and public interiors.
• Group 3: Limited performance; generally unsuitable for exits, corridors, or Class 2–3/9 buildings.
• Group 4: Generally prohibited in Class 2–9 buildings.

Testing Timber Fire Performance

Fire performance is assessed under AS 5637.1 using two recognised methods:

1. Cone calorimeter test (AS/NZS 3837): Measures time to ignition, heat release, total heat, and smoke production on a small sample.
2. Full-scale  room burn test (ISO 9705): Evaluates real-world fire behaviour, including flashover contribution.

"With independently tested performance, clear technical documentation and the correct system specification, timber linings allow designers to achieve both outstanding aesthetics and fire compliance."

The Glosswood Difference

At Glosswood, we believe designers shouldn't have to choose between aesthetics and compliance. That's why we've invested heavily in independent fire testing across our timber lining systems.

Our range now includes independently tested solutions capable of achieving Group 1, Group 2 and Group 3 fire classifications (depending on the product and installation system), giving architects and designers greater flexibility across a wide variety of commercial and residential applications.

"Fire compliance is no longer a barrier to using timber. By investing in rigorous independent testing, we're giving architects the confidence to specify real timber across more projects than ever before."

As with all fire-performance testing, classifications apply to the complete tested system and should always be verified against the relevant technical documentation for the intended application.

Key Terms at a Glance:

• NCC: Governs Group Numbers by building class.
• Group 1: Highest fire performance.
• AS 5637.1: Australian standard for testing and classification.
• AS/NZS 3837: Cone calorimeter test.
• ISO 9705: Full-scale room burn test.

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Disclaimer:

The information contained in this article is provided as general guidance only and should not be relied upon as project-specific fire engineering or building compliance advice. Building designers, architects, certifiers and contractors should always verify that the selected product and installation system complies with the requirements of the National Construction Code (NCC) and all applicable Australian Standards for the intended application. Product testing and classifications should be confirmed using current, independently verified test reports and technical documentation. While every effort has been made to ensure the accuracy of the information at the time of publication, Glosswood accepts no liability for any loss or damage arising from reliance on the information contained in this article.