Design of Light Timber-framed walls and floors for fire resistance, TR9 (1991)
- Valid from
- Information provider
- BRANZ Limited
- Peter Collier
- Information type
- Technical recommendation
Walls and floors are required in some buildings to comply with New Zealand Building Code requirements for fire resistance. Sometimes these can be of light timber framed construction.
Fire resistance of an element of construction is usually established by testing on a full sized prototype of the element. However, due to limitations on size and loading capacity of the testing equipment, and the cost of testing all possible combinations, it is often impractical to test the desired construction.
The methods of extrapolation described here relate to light timber framed wall and floor constructions respectively which are similar to a tested wall or floor prototype.
There are two extrapolation methods described here which apply to the design of light timber framed walls and floors respectively.
Using the results from a floor or wall prototype test, these methods enable designers to produce a wall or floor having at least the same structural fire resistance as the original prototype. These methods cannot be used to increase the fire resistance of tested designs.
These extrapolation methods are not intended to replace any accepted design method or code based on normal service criteria, including wind and earthquake etc. Therefore, designs produced by these methods should still be checked for compliance with other relevant service criteria.
The extrapolation method for wall design applies to any wall, of timber framed construction, either loadbearing or non-loadbearing, lined on both sides with a protective membrane fixed directly to the framing, which has been tested in prototype in accordance with a standard fire resistance test.
The extrapolation method for floor design applies to any loadbearing floor system lined on the underside with a protective membrane fixed directly to the timber framing, which has been tested in prototype in accordance with a standard fire resistance test.