Section 12(2)(b) in The Merchant Shipping (Crew Accommodation) Rules, 1960
(b)The sectional area of every part of the inlet and exhaust system (other than a par serving a drying room or locker) shall be at least [38.71 square centimetre] [Substituted by G.S.R. 61, dated 6th January, 1967] for each person for whose use at any one time the space is appropriated and shall not be less than [122.58 square centimetres] [Substituted by G.S.R. 61, dated 6th January, 1967] in all at any point in the system. The effective area of the inlet and exhaust system serving each space shall be capable of being adjusted from fully open down to a minimum of the [19.35 square centimetres] [Substituted by G.S.R. 61, dated 6th January, 1967] for each person likely to use the space at any time.