What is wrong with using fire intumescent paint to achieve fire group numbers?

Some ​companies are ​promoting the ​use of fire ​intumescent ​coatings in ​order to ​achieve a Fire ​Group 1 or Fire ​Group 2 rating ​when using ​timber wall or ceiling products. This ​includes claims ​of compliance ​for slotted, ​perforated, and ​slatted panels.​ On the face of it, there doesn’t seem to be a problem with this as it is generally in accordance with AS5637.1 and C1.10 of NCC 2019.

However, note ​the following ​regarding ​this:

  • These products ​have never ​been fire ​tested on ​perforated, ​slotted, or ​slatted panels.
  • The coating ​must be ​inspected ​annually to ​ensure it has ​not been ​removed, ​covered over, or ​tampered with.​ (Note that most ​maintenance ​managers would ​not be able to ​ensure this. How could they when this instruction is buried in a maintenance manual somewhere, and not in a large sign on the relevant wall!).
  • The coating ​typically takes ​3 weeks to cure.
  • Perforations ​or slots must ​be free of dust.
  • A 230-micron ​paint film is ​required for ​the base coat.​ This ​would be very ​hard to achieve ​on the edges of ​holes and slots ​of MDF panels ​as they are so ​porous and this ​would even be ​hard to achieve ​on the edges of interior timber battens. (Note this is typically applied on site – see diagrams below showing the effect of this).

The fact that a Codemark certificate is available is cold comfort. After all, a Codemark certificate can be withdrawn at any time.

As at the writing of this article, 46 Codemark certificates have been withdrawn, over against just 183 Codemark certificates that are still valid.

Thus, while ​the paperwork ​may be accepted ​by a BCA ​consultant, you ​would not have ​the assurance ​that there ​would not be a ​problem ​if there was a ​fire affecting your timber wall panels interior.

How intumescent paint must be applied as per certification (in red)

intumescent paint

How intumescent paint is applied in reality (in red)


The above listed variances between theory and what is practically achievable is why NSW has excluded coatings for use to achieve fire ratings in the BCA.

NCC 2019 Part C1.10 NSW (b): “Paint or fire-retardant coatings must not be used to achieve compliance with the required fire hazard properties.”

Unfortunately, even though the NSW government has specifically excluded intumescent paints from their version of the BCA, anyone with a fire safety engineering qualification and general fire safety engineering experience, can register under the DBPA and approve its use!

Such is the sad state of the compliance legislation in our country. Thankfully, due to the Shergold Weir Report, all states are now addressing these problems and omissions in their legislation, although these changes may take years to filter through and affect real change.

The variances between theory and what is practically achievable with intumescent paints is also why Supawood and other professional linings companies will not use or promote the use of intumescent paints to achieve fire compliance.

Supawood ensures all our fire certifications align with how our panels are actually installed on site. We give you peace of mind that one of our fire certifications represents exactly what gets installed in your project.

If you have any questions about achieving fire compliance in your project, please feel free to reach out for advice on this important topic here.

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