The best time to think about these requirements is early on in the design phase as you don't want to have to change things after the building is completed. Important changes were made to the fire sections of the New Zealand Building Code in April 2012 with further amendments since then. Surface linings are part of a system and that full system needs to be assigned a Group Number.

Dulux Material Group Numbers

Dulux have tested a number of systems on various substrates, to AS/NZS 3837 or ISO 5660 and the material group numbers are available on our website.

Material group numbers indicate the time a room fire will process from being a small fire to a large fire. This phenomenon is called "flashover" and can be tested by building a certain sized room, setting a fire and then measuring the time to "flashover" or completing a laboratory cone calorimeter test that is also used to create material group numbers, in addition to a table.

As general examples of what Group Numbers mean please see below:

Group Number 1 materials

These include non-combustible materials or those with limited combustibility. Examples are plasterboard and similar, low-hazard materials (no flashover in 20 minutes). These materials meet the flashover criteria of the performance requirement of Clause C3.4 (a) for exitways.

Group Number 2 materials

These typically include many fire retardant treated timbers (no flashover in ten minutes). These materials meet the flashover criteria of the performance requirement of Clause C3.4 (a) for crowd uses.

Group Number 3 materials

These typically include ordinary timber or similar products (no flashover in two minutes). These materials meet the flashover criteria of the performance requirement of Clause. C3.4 (a) for all other areas.

Group Number 4 materials

These typically include exposed polyurethane foams or similar products (flashover within two minutes). Note that these materials are potentially hazardous when installed as room linings and are not acceptable in occupied spaces.

Verification Method Update: July 2014

From July 2014 testing may not be required for many substrate/surface linings. The table A1 in the appendix of the document C/VM including amendment 4 can be used to apply a Group Number without further testing being required.

If you require a fire rating for a coating and substrate system please check the website for our latest test results. If your specified system is not there, please contact your Dulux Commercial Representative or 0800 800 424 as we are undertaking more testing regularly.

If you require the previous SDI and SFI fire indice test results these are also still available.