Classification of Lining Material Performance

The surface spread of flame classification of a lining should be ascertained by testing in accordance with BS 476: Part 7. The classifications given in such tests are Classes 1, 2, 3 and 4. Class 0 is achieved where a lining material or the surface of a composite product is either – (a) composed throughout of materials of limited combustibility; or (b) a Class 1 material which has when tested to BS 476: Part 6, a fire propagation index (I) of not more than 12 and a sub-index (i1) of not more than 6. A composite material of limited combustibility which does not have a surface complying with (a) or (b) should be classified by test. Class 0 is the highest classification and Class 4 materials are not acceptable.