53 Pa. Stat. § 24960
Where the seating capacity is for more than one thousand people there shall be at least two independent staircases with direct exterior outlets provided for each gallery. Where there are more than two galleries, one or more additional staircases shall be provided, the outlets from which shall communicate directly with the principal exit or other outlets. All said staircases shall be of width proportioned to the seating capacity as elsewhere herein prescribed. Where the seating capacity is for one thousand people or less, who direct lines of staircases only shall be required, located on opposite sides of the galleries, and in both cases shall extend from the sidewalk level to the upper gallery, with outlets for each gallery to each of said staircases. At least two independent staircases with direct exterior outlets shall also be provided for the service of the stage and shall be located on the opposite side of the same.
53 P.S. § 24960