Section 21(vi) in The U.P. Cinematograph Rules, 1951
(vi)The entrance to the projection room shall be through a closely fitting self closing door of fire-resisting material suitable placed and opening outwards and all openings, bushes and joints shall be so constructed and maintained as to prevent, as far as possible, the escape of any smoke into the auditorium. This door shall be kept closed at all times when not used for ingress or agrees. Channels of ventilation shall not be allowed to communicate direct with the auditorium. The projection room shall be provided with an opening or vent flue in its roof or upper part of its side wall leading to the outside air. The vent flue shall have minimum sectional area of 50 square inches and shall be fire proof:
