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 New requirements for interior surface finishes (July 2011)

fire testing.jpgNew requirements under the New Zealand Building Code will soon be in place for surface finishes.

In the proposed new Building Code Clause and Acceptable Solutions for fire safety, the testing requirements and classification of interior surface finishes will change.

Once the new Code clause and Acceptable Solutions come into force, there will probably be a 12-month transition period during which manufacturers will be able to test their products to the new regime so that their stated performance will align with the new requirements.

BRANZ can provide advice on the most appropriate test to meet the new Building Code requirements and our fire laboratory is accredited to carry out testing to both relevant standards - ISO 9705 and ISO 5660.

Classification of interior surface finishes

Interior surface finishes are classified from Group 1 (best) to Group 4 (worst) based on their measured time to flashover in the ISO 9705 fire test:

  • Group 1 materials include non-combustible materials or materials with limited combustibility such as plasterboard and similar materials (low hazard).
  • Group 2 materials typically include many fire-retardant treated timbers and similar materials.
  • Group 3 materials typically include ordinary timber products and similar materials.
  • Group 4 materials typically include exposed polyurethane foams and similar materials.These are hazardous when installed as room linings and are not permitted in occupied spaces.

Test methods and results

The reference test method is ISO 9705 - a full-scale fire test (ISO room test) - but most materials can be assessed using the small-scale test method ISO 5660 - the cone calorimeter test.

Materials that are unlikely to be suitable for testing in the cone calorimeter include those with foil facing or thin aluminium coverings on combustible cores and composite products with complex jointing systems where the ISO room test is the only suitable method.

The results of tests to ISO 9705 and ISO 5660 can also be used with compliance document Verification Method C/VM2 for fire safety, which can be applied to fire designs to demonstrate compliance with clause C of the New Zealand Building Code. Design Fire Scenario 8 (DFS8) applies to interior surface finishes within the Framework for Fire Safety.

The proposed changes will more closely align the testing requirements of the New Zealand Building Code with the Building Code of Australia.

For more information, please contact BRANZ Fire Testing Team Leader Peter Whiting - Peter.Whiting@branz.co.nz or (04) 238 1331.