Compliance with the fire behaviour of building materials is related to performance of standard issued by the British Standards Institution tests described in British Standards BS 476: part 3 to 31.
The reaction to fire tests classify the material in 4 categories from class 1 to class 4 connected with the 1.5 min and final flame spread according mainly to the BS 476-7 -surface spread of flame testing method (and to BS 476-6) fire propagation test- (see table below).
Table 1: BS 476 Fire classification Class | BS 476-7 Maximal final flame spread Limit mm | BS 476-6 Flame spread index FPI | Component | 1 | 165 | | Rooms Circulation spaces within dwellings | 1 | 165 | FPI<12 I.E. class 0 according to BS 476-6 | Other circulation spaces, including the common areas of flats and maisonettes | 2 | 455 | | | 3 | 710 | | Small rooms of area not more than 4m2 in a residential building and 30m2 in a non-residential building | 4 | Exceed class 3 | | |
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