23. There shall be above the stage of each theatre, one or more incombustible ventilators, each with an area equal to at least one-thirtieth of the whole area of the stage. Each ventilator shall be supplied with a valve arranged and counterbalanced so as to open automatically. The valve shall be closed when the ventilator is not in use, by means of a cord the end of which shall be at the prompter’s box. Such cord shall be of combustible material, and so arranged that if it breaks the ventilator will open automatically. The inspector may, at his discretion, require that such a ventilator be made in theatres built on or before the 25th of April, 1908.
R. S. 1964, c. 149, s. 23.