Fire safety – Building standards in England and Wales

The external envelope of a building should not contribute to undue fire spread from one part of a building to another part. This intention can be met by constructing external walls so that both of the following are satisfied.

The risk of ignition by an external source to the outside surface of the building and spread of fire over the outside surface is restricted
The materials used to construct external walls, and attachments to them, and how they are assembled do not contribute to the rate of fire spread up the outside of the building
The extent to which this is necessary depends on the height and use of the building

Building Type	Building Height	Less than 1000mm from the Relevant Boundary	1000mm or more from the Relevant Boundary
‘Relevant buildings’ as defined in regulation 7(4) [Annex 1]		Class A2-s1, d0(1) or better	Class A2-s1, d0(1) or better
Relevant residential purpose grounds/institutions/hospitals etc	More than 11m	Class A2-s1, d0(1) or better	Class A2-s1, d0(1) or better
	11m or less	Class B-s3, d2(2) or better	No provisions
Assembly and recreation	More than 18m – see Annex[1]	Class B-s3, d2(2) or better	From ground level to 18m: class C s3, d2(3) or better From 18m in height and above: class B-s3, d2(2) or better
	18m or less	Class B-s3, d2(2) or better	Up to 10m above ground level: class C-s3, d2(3) or better Up to 10m above a roof or any part of the building to which the public have access: class C-s3, d2(3) or better(4) From 10m in height and above: no minimum performance
Any other building	More than 18m	Class B-s3, d2(2) or better	From ground level to 18m: class C s3, d2(3) or better From 18m in height and above: class B-s3, d2(2) or better
	18m or less	Class B-s3, d2(2) or better	No provisions

Internal linings

Requirement B2: Internal Fire Spread (linings)

The surface linings of walls and ceilings should meet the classifications in the table below.

Location	Classification
Small rooms of maximum internal floor area of 4m2 Garages (as part of a dwelling house) of maximum internal floor area of 40m2	D-s3, d2
Other rooms (including garages), Circulation spaces within a dwelling	C-s3, d2
Other circulation spaces (including the common areas of blocks of flats)	B-s3, d2(1)

Please note: wallcoverings which conform to BS EN 15102, achieving at least class C-s3, d2 and bonded to a class A2-s3, d2, will also be acceptable.

Parts of walls in rooms may be of lower performance than stated in Table 4.1, but no worse than class D-s3, d2. In any one room, the total area of lower performance wall lining should be less than an area equivalent to half of the room’s floor area, up to a maximum of 20m2 of wall lining.