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LIGHTING AND VENTILATION OF ROOMS
a) Rooms: Every habitable room which should have for the admission of air and light, one or more apertures such as windows and fanlights, opening directly to the external air or into an open verandah and of an aggregate area, inclusive of frames, of not les than
i. One-tenth of the floor area excluding doors for dry hot climate.
ii. One-sixth of the floor area excluding doors for wet/hot climate.
No portion of a room should be assumed as lighted if is more than 7.5m away from the door or window which is taken for calculation as ventilating that portion.
Cross-ventilation by means of windows and ventilators or both shall be effected in at least living room of tenement either by means of windows in opposite walls or if this is not possible or advisable, then atleast in the adjoining walls.
b) Bathrooms and water closets: The rooms should be provided with natural light and permanent ventilation by one of the following means:
i. Windows having an area of not less than 10% of the floor area and located in an exterior wall facing a street alley, yard or an air shaft whose dimensions in the direction perpendicular to the window is not less than one-third the height of the building on which the window is located, subject to a minimum limit of 1m and maximum 6m.
ii. Skylights, the construction of which shall provide light and ventilation required in (i) above.
iii. Ventilation ducts: Provided such ducts have 130 square cm of area for each square meter of area with a minimum total area of 300 square cm and least dimension of 9cm.
c) Stores, backrooms: These will have atleast half the ventilation required for living room.
d) Basement and floors: Basements and rooms located therein except room shall be lighten and ventilated by windows in exterior walls having a ventilating area of not less than 2.5% of the floor area.
e) Kitchen shall be ventilated according to standards prescribed for habitable rooms near the ceiling as far as possible.
f) Stairways: every staircase should be lighted and ventilated from an open air space of not less than 3m depth measured horizontally in case of ground and one upper floor structure, 4.5 m in case of ground and two upper and in higher structure than this, the open air space shall not be less than 6m, provided that the lighting area shall not be less than 1 sq.m per floor height. Every staircase shall be ventilated properly.