Section 18 in The Chennai City Corporation Building Rules, 1972
18. Ventilation of buildings.
(1)Every room which is intended for human habitation shall be furnished with sufficient number of windows and ventilators totally providing a ventilation area of not less than one eighth of the floor area of the room, affording effectual means of ventilation by direct communication with the external air.(2)Windows and ventilators which open into a verandah shall be deemed to communicate with the external air, provided that such verandah is not more than three metres and seventy five centimetres wide and open throughout its entire length into space open to the sky, the width of such open space being double the width of the verandah and in no case less than one metre and seventy five centimetres.(3)Every domestic building shall be so constructed that every room intended to be used for purpose of human habitation shall have at least one side abutting for a length of not less than two and a half metres on an open space either external or internal. Such open space shall not be less than one metre and seventy five centimetres in width.(4)Every open space, external or internal, required by this rule shall be kept free from any erection thereon and open to sky.(5)This rule shall not apply to lavatories and bath rooms which shall have windows or ventilators of not less than half square metre abutting such open space.(6)A building shall not be held to contravene sub-rule (3) above, if one side of a room abuts on an external or internal verandah which in turn abuts 1 for not less than one half of its length on such open space.(7)This rule shall not apply to rooms provided with mechanical ventilation or air conditioning.
