Introduction

Building Regulations (Northern Ireland), Technical Booklets E and B, state that materials which form part of an external wall, or the external surface of a wall, shall be of the European Classifications set out in the documents. For your convenience, we have outlined extracts from the technical handbooks.

• For detailed guidance, refer to the full versions of technical booklets and amendments booklet linked above.

Technical Booklet E – Fire safety

External fire spread

Regulation 36: The external walls and roof of a building shall be so designed and constructed that they afford adequate resistance to the spread of fire over them, and from one building to another, having regard to—
(a) in the case of an external wall the use, position and height of the building; and
(b) in the case of a roof the use and position of the building.

Technical Booklet B – Materials and workmanship

Regulation 22: Interpretation
“External wall” of a building includes a reference to—
(a) anything located within any space forming part of the wall;
(b) any decoration or other finish applied to any external (but not internal) surface forming part of the wall;
(c) any windows and doors in the wall; and
(d) any part of a roof pitched at an angle of more than 70 ° to the horizontal if that part of the roof adjoins a space within the building to
which persons have access, but not access only for the purpose of carrying out repairs or maintenance.”.

Regulation 23: Fitness of materials and workmanship
(2) Subject to paragraph (3), building work shall be carried out so that materials which become part of an external wall, or specified attachment, of a relevant building are of European Classification A2-s1, d0 or Class A1, classified in accordance with BS EN 13501-1:2018.

(4) In this regulation—
(a) a “relevant building” means a building with a storey (not including rooftop plant areas or any storey consisting exclusively of plant rooms) at least 18 m above ground level and which—
(i) contains one or more dwellings;
(ii) contains an institution; or
(iii) contains a room for residential purposes (excluding any room in a hostel, hotel or boarding house); and

(b) “above ground level”, in relation to a storey, means above ground level when measured from the lowest ground level adjoining the outside of a building to the top of the floor surface of the storey.”.

2.14A: Materials in external walls of tall buildings
The Building Regulations restrict the use of combustible materials in the external walls of buildings with a topmost storey over 18 m in height.  Refer to regulation 23 of the Building Regulations and to Technical Booklet E, Section 5 for details.

Technical Booklet E – Fire safety

External fire spread – Section 5

Performance

0.14: Construction of walls – the fire resistance of an external wall and the combustibility of its external face are controlled to reduce its susceptibility to ignition from an external source and the danger from fire spreading up the external face of the building.  The materials used for external walls and attachments to them, should not contribute to the rate of fire spread up the outside of a building.

Combustibility of external walls

Regulation 23(2) applies to any building with a storey at least 18 m above ground level and which contains one or more dwellings; an institution; or a room for residential purposes (excluding any room in a hostel, hotel or a boarding house).  It requires that all materials which become part of an external wall or specified attachment achieve European Class A2-s1, d0 or Class A1, other than those exempted by Regulation 23(3).

Note:

• Included are student accommodation, care homes, sheltered housing, hospitals, and dormitories in boarding schools.

• An external wall includes anything located within any space forming part of the wall (including air bricks, plenums, HVAC supply and extract ducting, ventilation grilles, and cavity weep hole ducts).

• A specified attachment includes a balcony attached to an external wall, a device for reducing heat gain within a building by deflecting sunlight which is attached to an external wall and a solar panel attached to an external wall.

External surfaces

5.3: The external surface of an external wall (i.e. outermost external material) should meet the requirements given in Table 5.1A relevant to the height of the building and the distance between the building and the relevant boundary.

Rytons A1^® Fire-rated Range