Summary

Fire resistance of a completed timber building is achieved by a combination of: the internal lining material, the timber structure, the integrity and the insulation for each element of construction.

Fire resistance requirements for elements of construction are defined in Building Regulations. For example Approved Document B, volume 1 for dwelling houses, table A1 specifies a 30-minute fire resistance for most building elements, whereas volume 2 for other buildings specifies a 60-minute fire resistance, from a loadbearing perspective.

Equal or reduced levels of fire resistance are usually required for integrity and insulation purposes.

Key Information

Fire resistance performance is determined by approved laboratory tests carried out to the requirements of British or European Standards as stated in Appendix A of Approved Document B.

The European system allows generic groups of products with known and predictable fire performance to be “Classified Without Further Testing” (CWFT).

Building Regulations Part B requires various building elements to exhibit at least a minimum level of fire resistance.

Intermediate floors require a minimum of 30 minutes of fire resistance on the underside and party (compartment) floors require 60 minutes – normally provided by one or two layers of gypsum plasterboard, although other suitable materials may be used.

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