(1) All buildings with a capacity greater than is permitted for a division under Table I shall be subdivided into divisions, and no such division shall have a greater cubic capacity than is permitted in that Table.

(2) Such cubic capacity may be measured exclusive of the thickness of the containing walls or floor-slabs, and exclusive also of the whole roof construction, including the ceiling, where this construction is constructed if non-combustible material.

(3) Where of the roof construction, including the ceiling, is constructed of combustible material, the volume, of the whole roof construction shall be included in assessing the volume of the division.

(4) The cubic capacities specified in column 3 of Table I for single-storey buildings without basements, or divisions without basements, may be doubled in the case of buildings or divisions provided with an approved sprinkler system throughout the building or division, or with the approval of the local authority an alternative automatic extinguishing system, and, in the case of buildings or divisions of grade A construction, having low or moderate fire-load, which are so provided, such capacity may be unlimited.

(5) The cubic capacities specified in column 4 of Table I for multi-storey buildings may be increased at the discretion of the local authority, under such conditions as the local authority may prescribe, in the case of buildings or divisions provided with an approved sprinkler system throughout the building or division, or with the approval of the local authority an alternative automatic extinguishing system.

(6) Notwithstanding the particular requirements of section 8 and 9, it shall be permissible to use unprotected steel columns and beams in any single-storey building or division of a building referred to in subsection (1) which is wholly used for any of the following occupancies—

a) Business, commercial or industrial occupancy of low or moderate fire-load;

b) Storage occupancy, having a low or moderate fire-load;

c) Public and assembly occupancy in which—

i) Category A, mentioned in column 5 of Table I, shall include occupancies for theatres, cinema, cafes and exhibition-buildings; and

ii) Category B, mentioned in column 5 of Table I, shall include class-rooms, club-rooms, clinics and places of worship;

Both categories having a population not exceeding 300.

(7) In Table I, construction referred to in sub-section (6) is termed “unprotected steelwork construction”, and all other construction is termed “fire-protected construction”.

TABLE I
MAXIMUM CUBIC CAPACITIES OF BUILDINGS OR DIVSIONS
*Unlimited, if approved sprinkler system or approved alternative automatic extinguishing system is installed