Fire Safety

According to New Zealand Building Code Clause C3 (Fire affecting areas beyond the source), floor and wall surfaces must meet specific fire performance criteria to limit fire spread and smoke development in the event of a fire. These requirements apply to commercial, multi-unit residential, and public buildings.

Always check project-specific requirements against the latest Building Code provisions and the relevant Acceptable Solutions or Verification Methods.

Fire Safety Requirements for Flooring

Flooring must meet minimum Critical Radiant Flux (CRF) values to reduce fire spread. CRF measures the minimum radiant energy needed to keep flame spreading across a floor surface.

The higher the CRF, the better the fire performance.

CRF is also referred to as Critical Heat Flux (CHF) within the ISO 9239-1 standard and on most fire test certificates.

Minimum CRF Requirements for Flooring

The above requirements apply to apartments, commercial buildings, and industrial facilities, but not to standalone homes, townhouses, and B&Bs or boarding houses with up to 5 paying guests.

Flooring that achieves a CRF of at least 4.5 kW/m² can be used in all buildings regardless of whether sprinkler protection is provided.

Always check the product’s technical specifications or fire certificate before specifying. If a residential flooring product does not have a verified CRF, it is only allowed in standalone homes and townhouses, not in multi-residential buildings such as apartments.

How to Determine CRF

CRF can be determined using one of the following methods:

1. Testing to ISO 9239-1
2. Assigning generic CRF values to common flooring materials

Generic CRF Values for Selected Flooring Materials

When using generic CRF values, waterborne or solvent-borne coatings on concrete or wood flooring are allowed as long as they are ≤ 0.4 mm thick and ≤ 100 g/m².

Fire Safety Requirements for Wall Coverings

Internal wall linings are rated by Group Number, which indicates how materials behave in a fire.

The lower the Group Number, the better the fire performance.

Requirements depend on where the wall is and whether sprinklers are installed.

Maximum Permitted Group Numbers for Wall Coverings

Group Number requirements apply to apartments, commercial buildings, and industrial facilities, but not to standalone homes, townhouses, and B&Bs or boarding houses with up to 5 paying guests.

Wall coverings with a Group 2 rating or better are permitted in all sprinklered spaces, while those with a Group 1-S rating can be used in any building whether sprinklers are installed or not.

Wall coverings with a Group 3 rating can go up to dado height (below 1.2m) in unsprinklered classrooms and school corridors, provided the following conditions are met:

• The occupant load is under 250
• The area is located at ground level
• The space is served by at least two fire exits

Flooring materials without a Group Number may be extended onto walls and other vertical surfaces if the combined vertical coverage within a room does not exceed 5 m².

How to Determine Group Number

A Group Number can be determined using one of the following methods:

1. Testing to ISO 9705 or ISO 5660
2. Classifications from European fire testing (EN 13501-1:2018)
3. Classifications from Australian fire testing (AS 5637.1:2015)
4. Assigning generic Group Numbers to selected wall substrates and coatings

Group Numbers from European fire classifications (EN 13501-1:2018)

Group Numbers from Australian fire classifications (AS 5637.1:2015)

Generic Group Number for wood substrate

The wallcovering and flooring products listed below have Group Numbers determined through one of the methods mentioned above.

Group Numbers for selected Belgotex flooring and wall coverings