(1) Grade C construction means construction complying with the particular requirements of this section.

(2) Structural members. – Except as otherwise provided in subsections (3) and (4), all structural members shall have fire-resistance ratings of not less than the following—

a) occupancy-units with high fire-load, one hour;

b) occupancy-units with moderate fire-load, half an hour; and

c) occupancy-units with low fire-load, no requirement.

(3) External walls and external members of structural frames. – External walls and external members of structural frames of a building which are within the distances from the nearest lateral boundary of the stand on which such building is erected or from another building on such stand, specified in column 1 of Table VII, shall have fire-resistance ratings or fire protection, as the case may be, not less than the appropriate rating or protection specified in column of that Table.

Table VII
Fire-Resistance Ratings And Fire Protection For External Walls And External Members Of Structural Frames For Grade C Construction

(4) Where, in consequence of additions, any external wall of an existing building will be at a leaser distance from the nearest lateral boundary or from another building on the same stand than is required for the increased floor area of the ground storey set forth in Table IX resulting from such additions, such wall shall be permitted to remain in its existing position, if every external wall or external structural frame which is a part of such additions is erected in accordance with the requirements set out in Table VIII below.

Table VIII
Requirements Following On Erection Of Certain Additions

(5) Subject to the requirements of subsection (7), the distance between any external wall or external structural frame of a building which is of combustible construction and the nearest lateral boundary of the stand on which such building is erected, or between such wall or member and another building on the same stand, shall be not less than that specified in Table IX, in which such walls or frames are placed in the following classes—

Class A- External walls or external structural frames of combustible construction protected externally with approved non-combustible material; and

Class B-External walls or external structural frames of combustible construction not falling into class A.

TABLE IX
BOUNDARY OR SEPARATION DISTANCES FOR EXTERNAL WALLS OR EXTERNAL MEMBERS OF STRUCTURAL FRAMES OF A BUILDING WHICH ARE COMBUSTIBLE—GRADE C CONSTRUCTION

(6) Floors. – All floors shall have a fire-resistance rating of not less than half an hour, and all floors constructed directly over basements shall be of non-combustible materials as a floor finish.

(7) Roof assemblies. – No roof of a building shall be covered with thatch or wooden shingles:

Provided that a building not exceeding 1 400 cubic metres in capacity and having walls of non-combustible materials and a low fire-load may have a roof covered with thatch or wooden shingles if –

a) Such building is not less than 10 metres from any boundary whatsoever of the stand on which such building is to be erected; and

b) Such building complies with the relevant requirements of subsection (8) to (11) of section 10.

(8) The covering of all roofs of buildings having high or moderate fire-load occupancy-units shall be of non-combustible materials:

Provided that, where a roof construction is of concrete or other non-combustible construction, bituminous felt or other approved material may be used to cover such roof construction.

(9) All roof-members in buildings having a high fire-load shall be separated from the room or rooms below such members by a ceiling construction or other protection having a fire-resistance rating of not less than half an hour.

(10) Partition-walls. – Every partition-wall in a basement shall be of non-combustible material, and every doorway in such partition-wall shall be fitted with a fire-door having a fire-resistance rating of not less than half an hour.