(1) (a) The Board of Councillors may, by public notice, direct that within certain limits to be fixed by it, the roofs and external walls of huts or other buildings shall not be made or renewed with grass, mats, leaves or other highly inflammable materials without the consent of the Chairman in writing.
(b) The competent authority may, at any time, by written notice, require the owner of any building, which has an external roof or wall made of such material as aforesaid, to remove such roof or wall within such reasonable time as shall be specified in the notice, notwithstanding that the public notice has not been issued or that such roof or wall was made with the consent of the competent authority on or before the issue of such notice.
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(2) The floors of the lobbies, corridors, passages and landings of a building other than residential or educational shall be constructed of incombustible materials; the doors shall be constructed of fire-resisting materials and the flights of stairs shall be constructed either of incombustible materials or fire-resisting material.
(3) The following material shall, for the purposes of this rule, be deemed to be incombustible:—
(a) brick-work constructed of bricks, well-burnt, hard and sound, properly bounded and solidly put together with—
(i) mortar compounded of lime and sharp clean sand, hard clean broken brick, broken flint, grills or slag, well pulverized, or
(ii) cement mixed with any of the materials mentioned in sub-clause (i);
(b) granite or other stone which is suitable for building purposes by reasons of its solidity and durability;
(c) slate, tiles, bricks and terracotta, when used for coverings or corbels;
(d) flag-stones when used for floors over arches, if not exposed on the underside and if not supported at the ends only;
(e) concrete, composed of broken brick, stone chippings or selected slag and lime, cement or calcined gypsum, when the concrete is used for filling in between joists of floors to a depth of not less than ten centimetres;
(f) any combination of concrete, steel or iron or any other materials approved in this behalf from time to time by the Board of Councillors.
Explanation.—In this rule, the expression brick, lime or cement shall mean respectively such brick, lime or cement as conform to the standard and quality specified in this behalf in the latest edition of the National Building Code.
(4) The following materials shall, for the purpose of sub-rule (2), be deemed to be fire-resisting, but not incombustible:—
(a) sal, teak, and other hard timber, when used for beams or posts or in combination with steel, the timber and the steel (if any) being protected by plastering in cement or other incombustible or non-conducting external coating;
(b) in the case of staircases, sal, teak or other hard timber, not less than four centimetres thick; and
(c) in the case of staircases, sal, teak or other hard timber, the treads and risers being not less than four centimetres thick.