Which Lining Products Are Compliant Under the NCC?
Selecting a compliant lining system is not simply a matter of finding a product with a stated Fire Group number. Compliance under the NCC depends on whether the tested evidence matches the actual installed system.
This distinction is where many projects encounter risk.
Compliance Starts With the Installed System
The NCC requires that Fire Hazard Properties relate to the material, component or assembly as installed, not just the base material in isolation.
This means:
- A Fire Group classification is only valid for the system that has been tested or properly assessed.
- If the installed lining differs from the tested prototype, the classification may no longer apply.
Why Many “Compliant” Products Are Not Always Compliant
It is common to see products promoted with a Fire Group classification derived from AS 5637.1 using AS/NZS 3837 test data.
That approach can be valid, but only under specific conditions.
AS/NZS 3837 is a small-scale test, typically applied to flat, continuous materials. The resulting Group number may be appropriate for that exact form.
However, once the product is modified, the situation changes.
When a Group Number May No Longer Apply
A Fire Group classification should be carefully reviewed where the product is:
- Perforated or acoustically open
- Installed with gaps between elements
- Used as a slatted or batten system
- Configured differently from the tested specimen
These features can change fire behaviour by increasing exposed surface area, allowing airflow, and altering how heat penetrates the system.
Compliance must be demonstrated for the installed system, not the base material in isolation.
AS 3837 vs AS 5637.1, What Matters
AS 5637.1 is the classification framework used by the NCC. It determines whether a product can be classified using prediction methods or whether full-scale testing is required.
In any cases involving joints, gaps or openings, the prediction method based on AS/NZS 3837 is not valid under AS5637.1.
These systems typically require classification based on AS ISO 9705 full room burn testing.
Fire Group Classification vs Non-combustibility
Not all compliance requirements are the same.
Some applications require a Fire Group classification (Group 1, 2, 3 or 4), while others require materials to be non-combustible under the NCC.
These are different compliance pathways and should not be confused.
A product may achieve a Fire Group classification and still not meet a non-combustibility requirement, and vice versa.
What Building Surveyors Look For
From a certification perspective, the key question is:
Does the evidence demonstrate compliance for the product as it will be installed?
Surveyors will typically consider:
- Whether the tested configuration matches the proposed design
- The presence of joints, gaps, perforations or open geometry
- The test method used for classification
- Whether any variation has been appropriately assessed
If there is a mismatch, additional justification or testing may be required.
Common Misconceptions
“This product has a Group 1 certificate, so it’s compliant”
Only if the installed system matches the tested system.
“Fire retardant treatment guarantees compliance”
Treatment may improve performance, but the system still needs to be tested or assessed in its final configuration.
“If the base board is compliant, the system is compliant”
Changes to geometry, spacing or assembly can invalidate that assumption.
Practical Steps to Confirm Compliance
Before specifying a lining system, confirm:
- The Fire Group classification and test method
- The exact configuration that was tested
- Whether your design matches that configuration
- Whether any variations have been formally assessed
If these do not align, the classification may not apply.
Where SUPAWOOD Fits
SUPAWOOD lining systems are tested as complete systems, including configuration, backing and geometry, rather than relying solely on base material performance.
This approach aligns with the NCC requirement to assess the installed system and provides clearer evidence for certification.
Final Takeaway
A lining product is not compliant simply because it has a Fire Group number.
It is compliant only when:
- the classification method is appropriate, and
- the installed system matches the tested or assessed configuration
That distinction is what separates compliant specification from compliance risk.
Need Help Identifying a Compliant Lining System?
For a clear breakdown of Fire Group requirements and which SUPAWOOD systems meet them
For guidance on selecting the correct Fire Group for your project