Clause 3.1 General Clause 3.2 Provision of compartment walls and compartment floors Clause 3.3 Fire resistance of elements of structure Clause 3.4 Test of fire resistance Clause 3.5 External wall Clause 3.6 Separating walls Clause 3.7 Compartment walls and compartment floors Clause 3.8 Protected shafts Clause 3.9 Protection of openings Clause 3.10 Exit staircases Clause 3.11 Concealed spaces Clause 3.12 Fire stopping Clause 3.13 Restriction of spread of flame over surfaces of walls and ceilings Clause 3.14 Roofs Clause 3.15 Materials for construction Clause 3.16 Use of plastic material Annex 3A - Notional Periods Of Fire Resistance Annex 3B - Permitted Limits Of Unprotected Areas

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Clause 3.13 Restriction of spread of flame over surfaces of walls and ceilings

CPFPRTS 2022

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3.13.1 Requirements for Class 0

Any reference to a surface being Class 0 shall be construed as a requirement that:

a. the material of which the wall or ceiling is constructed shall be non-combustible throughout, or

b. The surface material (or, if it is bonded throughout to a substrate, the surface material in conjunction with the substrate) shall have a surface of Class 1 when tested to BS 476: Part 7 and if tested in accordance with BS 476: Part 6 shall have an index of performance (I) not exceeding 12 and a sub-index (i1) not exceeding 6.

3.13.2 Requirements for a class other than Class 0 classification

Any reference to a surface being of a class other than Class 0 shall be taken as complying with the relevant test criteria as to surface spread of flame specified in relation to that class in BS 476: Part 7.

3.13.3 Classification

Class 0 shall be regarded as the highest class followed by Class 1 as set hereunder:

a. Class 0 - Surface of no flame spread. Such surfaces shall conform to the requirements of Cl.3.13.1.

b. Class 1 - Surface of very low flame spread. This refers to surfaces on which during the first 1½ mins of test, the spread of flame does not exceed 165mm and the final spread of flame does not exceed 165mm under the relevant test conditions.