Last edited 06 Aug 2021

Material of limited combustibility

Approved document B of the building regulations 'Fire Safety', defines limited combustibility as:

A material performance specification that includes non-combustible materials, and for which the relevant test criteria are set out in Appendix A, paragraph 9.

Paragraph 9 states :

Materials of limited combustibility are defined in Table A7: a. (National classes) by reference to the method specified in BS476: Part 11:1982; or

b. (European classes) in terms of performance

When classified as class A2-S3, d2 in accordance with BS EN 13501-1:2007, Fire classification of construction products and building elements, Part 1 - Classification using data from reaction to fire tests when tested to BS EN ISO 1182:2002, Reaction to fire tests for building products - Noncombustibility test or BS EN ISO 1716:2002 Reaction to fire tests for building products - Determination of the gross calorific value and BS EN 13823:2002, Reaction to fire tests for building products - Building products excluding floorings exposed to the thermal attack by a single burning item.

Table A7 also includes composite products (such as plasterboard) which are considered acceptable and where these are exposed as linings they should also meet any appropriate flame spread rating.

Table A7 is shown below:

Approved document b table a7.jpg

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