Exit stairs from each gallery shall be placed in smokeproof and fireproof towers, or in lieu thereof, an approved form of open air stairway may be used. The minimum width of exit stairways shall be 4 feet, except that their width may be reduced fifteen per cent if located in a fireproof and smokeproof tower having no openings except to an outside balcony and to court grade. Exit stairs shall have risers not exceeding 7 3/4 inches, and treads not less than 9 1/2 inches exclusive of nosing. The stairs for the exits from each tier shall extend to the court or street grade independently of the stairs or exits from other tiers. Outside balconies shall be at least as wide as the stairways which they serve, but in no case less than 6 feet. No riser shall be nearer than 1 foot to the door opening.
All exit balconies and stairs shall be constructed of steel throughout or of other forms of incombustible construction approved by the- Building Inspector. Risers, treads, platforms and balconies must be solid without slats, and the construction shall be of strength sufficient to safely sustain a live load of 100 pounds per square foot. Sheet metal or other suitable solid material shall be provided to a height of not less than 4 feet on the outer side of all these open air stairs, balconies and platforms. All open air stairs, balconies and platforms shall be covered with a metal hood or awning to be constructed in such a manner as shall be approved by the Building Inspector. There shall be no openings in any theatre wall between the outside balconies or stairways and their covers, except the required exits from the tier served by said stairs and balconies. No person of the audience must be obliged to pass alongside of more than one exit doorway after reaching an outside balcony to get to the ground. All exit stairs and balconies shall be kept free of obstructions of every kind including snow and ice.
At least two independent exterior exits shall be provided on a level with the stage for the service of the stage and floors below same. These exits shall be at opposite sides of the stage. Each tier of dressing rooms shall have an independent exit leading directly to a fire escape or to a court or street. No ladder fire escapes shall be permitted. The fly galleries shall be provided with adequate means of exit. All exits and fire escapes from the stage section shall be independent of the exits for the audience above the court or street grade. Stairs, if any, leading down from stage level shall be inclosed and protected by fireproof door.
Every building used for theatrical or operatic purposes or motion picture shows shall have at least the front or one side wall bordering on a street, and not less than one-half of the openings required for entrance of the audience to the auditorium as hereafter specified shall be provided in such' wall or walls.
There shall be reserved for exit purposes an open court or space on the side or sides of the building as follows:
In the case of a plot with streets on front, rear and both sides, or in the case of a double corner plot where both sides of the theatre border on the streets, no courts will be required. On a double corner, single corner or inside plot when one side only of the building borders on a street, one court will be required located on the opposite side. On an inside plot where only the building front borders on the street, courts will be required on both sides.
In buildings used for motion picture shows and having no stage, the exits and courts above required may be replaced by equivalent exits and courts at the rear if consistent with the adequate distribution of the entire entrance and exit facilities.
The minimum width of open courts shall be 8 feet when the total capacity is 750 or less; 10 feet when the capacity is between 750 and 1,000; and when the capacity exceeds 1,000 people the width of the courts shall be increased 1 foot for each additional 500 people or fraction thereof in excess of 1,000.
Said open court or courts shall extend at least from the line of the proscenium wall forward the length of the auditorium to the wall separating the same from the entrance lobby or vestibule. This entire court area shall be open to the sky, except that stairs and smokeproof towers may occupy part of the court space if the required width of exit passageway is not obstructed.
Where said emergency courts do not open directly on a street a separate and distinct corridor or passage shall continue directly to the street, around the building or through such structure as may be or may have been built on the street, but no such passageway shall pass under any portion of the auditorium or stage. Said corridors or passages shall be constructed fireproof all the way to the street in same manner as provided for the construction of corridors for entrances hereinbefore described. The corridor or passage leading from the court to the street shall be at least as wide as the court and there shall be no projections into the passage. The outer openings may be provided with doors or gates opening outward. During the performance these doors or gates shall be kept open; at other times they may be closed and fastened by movable bolts.