(1) Minimum area of openings. – Every habitable room shall have required ventilation-openings in the walls of an aggregate are of not less than 5 per centum of the floor area, but in no case less than 0,5 square meter:

Provided that, in the case of habitable rooms having a floor area exceeding 50 square meters, the local authority may permit ventilation-openings, other than skylights, in roofs of the monitor, saw-tooth or similar types in lieu of part of the ventilation-openings in walls, of an aggregate area not exceeding half the area afore mentioned.

(2) Position of openings in walls. – Subject to the provisions of section 6, required ventilation-openings in the walls of any habitable room shall be so positioned that they are contained in an external wall or walls.

(3) Measurement of are of required ventilation-openings. – In computing the area of required ventilation-openings in the walls of a room, the following provisions shall apply—

a) Such area shall be measured in the plane of the wall;

b) Where ventilation-openings are covered by wire gauze used as mosquito- or fly-screening, the ventilating are shall be taken as 40 per centum of the net area, excluding frames, of the openings obstructed by such gauze.

(4) Requirements for cross-ventilation. —Where the ventilation-openings required under subsection (2) are situated in one external wall, additional ventilation shall be provided by means of –

a) Permanently open ventilation openings having a total effective open area of not less than 0,03 square meter so placed as to secure cross-ventilation and such openings shall be a minimum of 2 meters from the floor; or

b) Other controlled ventilation devices to the satisfaction of the local authority.

(5) Required ventilation-openings in rooms containing screens and partitions. – Where a habitable room, which complies with the requirements of this Chapter, is subdivided by means of screens or partitions which do not exceed 2,1 meters in height, no allowance need be made for the effect of such subdivisions in determining the positions of the required ventilation-openings for such room.

(6) Where subdivisions of a habitable room are formed by screens or partitions higher than 2,1 meters, each such subdivision shall be ventilated either as if it were a separate habitable room or by means of mechanical ventilation to the approval of the local authority.

(7) Mechanical ventilation. – A means of machinal ventilation to argument the natural ventilation requirements of this section may be utilized to the approval of the local authority.