No portion of any building hereafter erected or altered, used or intended to be used as a theatre, opera house, or motion picture show, shall be occupied or used for any business dealing in any article or material dangerous to life in the opinion of the Building Inspector.
No workshop, storage or general property room shall be allowed in or under the auditorium, above the stage or under the same, or in any of the fly galleries, but such rooms or shops may be located in the rear of, or at the side of the stage, and in such cases they shall be separated from the stage vertically and horizontally by a brick or concrete wall not less than 12 inches in thickness or other equally efficient cut-off, and the openings leading into said portion shall have approved self-closing fire doors on one side of the wall. (See Rules and Requirements of the National Board of Fire Underwriters for Fire Doors.)
No sleeping accommodations shall be allowed in any part of the building communicating with the auditorium or stage.
Interior walls or partitions built of fireproof materials shall separate the auditorium from the entrance vestibule, and from any communicating room or rooms over or under the same, also from any lobbies, corridors, refreshment or other rooms forming part of the theatre; and in all such walls the windows and door frames and all sash and doors shall be of incombustible construction, and the sash made stationary and glazed with wired glass not less than 1/4 inch in thickness and each pane or unit measuring not more than 720 square inches; the doors shall be self-closing.
All floor surfaces shall be of cement or other incombustible material and no wood boards or sleepers shall be used as a covering over these floors, seat platforms, aisles, steps, landings, passages or stairs.
No combustible doors or trim shall be used in the auditorium, and none of the walls or ceiling shall be covered with wood sheathing, wood wainscoting, or other combustible material, but this shall not preclude the construction of a wood sounding board over orchestra pit when the same extends back of and below the overhang of the stage, provided the said wood sheathing be properly fire stopped by a 12-inch brick wall back of same, and also have a proper fireproof construction directly under the overhang of the stage extending from the brick wall to the apron of stage.
There shall be no more than 11 feet rise, measured vertically in any aisle in any gallery without direct exit, by tunnel or otherwise to a corridor or passage with a free opening to the gallery stairs or other direct discharge to the street. At such elevation of 11 feet or less an intervening or cross aisle leading directly to an exit may be substituted for the tunnel. No such tunnel or cross aisle shall be less than 4 feet wide in the clear.
No platforms in galleries formed to receive the seats shall be more than 21 inches in height of riser nor less than 32 inches in width of platform. No such platform shall be nearer than 8 feet from the ceiling.
Width of. Aisles shall be not less than 3 feet wide at the beginning and all aisles shall be increased in width toward the exits and entrances at the rate of not less than 3 inches to 10 feet of run.
Floors in auditorium at all exits shall be flush with adjacent inside floors and shall extend for an unbroken width of not less than 4 feet in front of each exit, but no step downward shall be nearer than 1 foot to the door opening.
Steps in aisles shall be the full width of the aisle. No risers shall be more than 9 inches in height, and no tread shall be less than 10 inches in width, and whenever the rise of seat platforms is 4 inches or less, the floor of the aisles shall be made as a gradient. Where steps are placed in passages they shall be grouped together and shall be clearly lighted. No stool, seat or other obstruction shall be placed in any aisle.
The width of passages and hallways shall be computed in the same manner as that hereinafter provided for stairways, but no passage may be less than 5 feet in width.
All passages, hallways, and stairways leading from any balcony or gallery in any direction shall permit of free passage to an exit, without returning.
The aggregate capacity of the foyers, lobbies, hallways, passages and rooms for the use of the audience, not including aisle space, shall on each tier be sufficient to contain the entire number to be accommodated on said tier, in the ratio of 150 superficial square feet of floor for every hundred persons.
The term "exit" as used in this section refers to emergency exits only; the term "entrance" refers to all other, traffic ingress or egress.
The combined width of entrances and exits for each tier, likewise their stairs, shall provide 1 foot of width for each 20 persons to be accommodated in that tier.
A common place of entrance may serve for the orchestra floor of the auditorium and the first gallery, provided such entrance and the passages leading thereto are of the width required for the aggregate capacity of these two tiers.
Separate places of entrance shall be provided for each gallery above the first.