Section 23.93. Class III buildings

(a) Walls. The walls of drycleaning, dyeing, tumbler or drying rooms shall be of fire-resistive construction, the walls of which may be of brick, concrete block laid in cement mortar or of reinforced concrete at least 8 inches in thickness. Interior dividing partitions shall be of construction equal to at least 2 hours fire resistivity.

(b) Multiple story. When a drycleaning or dyeing room is located in a multiple story building, the remainder of the building may not be used for purposes of public assembly or for living, housing or dwelling purposes. The building shall be of fire-resistive construction, the walls of which may be of brick, concrete block laid in cement mortar or of reinforced concrete at least 8 inches in thickness.

(c) Roof. The roof, ceiling or other construction shall be of fire-resistive construction rated one hour fire-resistive as classified in accordance with the Standard for Fire Tests of Building Construction and Materials and listed by Underwriters’ Laboratories, Inc. Hinged skylights of metal sash and wire glass shall be placed in the roof of each drycleaning or dry-dyeing room. They shall occupy an area equal to at least 1/8 the floor area of the room. Skylights shall open under pressure in case of an explosion and close automatically thereafter. The roof covering shall be of incombustible material.

(d) Floor. The floor of every drycleaning, dyeing, tumbler or drying room shall be of concrete construction at least four inches in thickness and shall not be lower than the surface of the earth surrounding any wall in which there is an opening or vent. If any such room is located over a basement, the floor of such room shall be liquid and vapor tight.

(e) Doors and windows. All doors shall be at least class B self-closing fire doors as classified by the Underwriters’ Laboratories, Inc. All window openings shall be protected with metal sash and wire glass. Doors and windows shall open outward.

(f) Intercommunicating openings. Intercommunicating openings from drycleaning, tumbler and drying rooms shall be provided with fire-resistive, self-closing doors, classified by Underwriters’ Laboratories B label or better.

(g) Egress. Any room used for the purpose of drycleaning or dyeing shall have at least one exit which opens to the outside of the building or to an interior fireproof fire structure. No less than two means of egress shall be provided. They shall be unobstructed and ready for use at all times.

(h) Sewer connection. There shall be no direct sewer connection with the drycleaning, tumbler or dyeing room.

(i) Basement cellar. Any basement, cellar or open space below the first story of any building in which a drycleaning plant is located shall be used only by the person, partnership or firm operating such plant.

(j) Exhaust fan. There shall be installed in such basement, cellar or open space, an exhaust fan of sufficient capacity, and a flue or flues of noncombustible material adequate to prevent concentration of vapors above the maximum concentrations as specified in this subchapter for drycleaning or dyeing rooms.