Fire ratings

Current MBIE information on substrate Fire Group Number ratings & Critical Radiant Flux values for Interiors.

Source: C/VM2 Verification Method: Framework for Fire Safety Design For New Zealand Building Code Clauses C1-C6 Protection from Fire – Amendment 6.

• Click this link to download: NZBC-CVM2-protection-from-fire-amendment-6
• For any queries regarding Fire Group ratings please contact Resene Technical Services: advice@resene.co.nz

Substrate Fire Group Number Ratings (Interiors):

• It is important to note that fire group number ratings are determined by the substrate's own uncoated performance and that decorative waterborne or solvent borne paint and clear coatings etc applied at less than 0.4mm thick will not alter the substrate's own fire group number rating. (a standard 3 coat paint system, primer/sealer plus 2 top coats will usually not exceed 120 microns (0.12 mm) dry film thickness).

• The only way currently to improve a substrate's Group number is to use an intumescent coating system.

• Decorative waterborne or solvent borne paint and clear coatings are only tested in combination with the applicable substrate and are not themselves "Fire Rated".

• Manufacturers own Group Number test reports are for Manufacturers internal use only and not required for "Consenting" process etc.

• The table below is typically all that is required for Council consenting process. › Download (PDF)

• The most common query we receive regarding Fire Group number ratings:

  • Question – Can decorative paint coating system achieve Fire Group number 2-S for timber wall or ceiling linings etc?
  • Answer – No, you require a full Intumescent coating system to improve Wood/Timber substrates from Group Number 3 to Group Number 2-S.

Critical Radiant Flux (CRF) for some flooring materials:

• It is important to note that Critical Radiant Flux (CRF) ratings relate directly to the substrate's own uncoated CRF value and that decorative waterborne or solvent borne paint & clear coatings etc applied at less than 0.4mm thick will not alter the substrate's own Critical Radiant Flux value.

• The table below is typically all that is required for Council consenting process. › Download (PDF)