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Subchapter 7. General Industry Safety Orders
Group 20. Flammable Liquids, Gases and Vapors
Article 141. Container and Portable Tank Storage

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§5534. Design and Construction of Inside Storage Rooms.

(a) Inside storage rooms shall be constructed to meet the required fire-resistive rating for their use. Such construction shall comply with the test specification set forth in Standard Methods of Fire Tests of Building Construction and Materials, NFPA No. 251-1972. Where an automatic sprinkler system is provided, the system shall be designed and installed in an approved manner. Openings to other rooms or buildings shall be provided with noncombustible liquid-tight raised sills or ramps at least four inches in height, or the floor in the storage area shall be at least four inches below the surrounding floor. Openings shall be provided with approved self-closing fire doors. The room shall be liquid-tight where the walls join the floor. A permissible alternate to the sill or ramp is an open-grated trench inside of the room which drains to a safe location. Where other portions of the building or other properties are exposed, windows shall be protected as set forth in the Standard for Fire Doors and Windows, NFPA No. 80-1974, for Class E or F openings. Wood at least one-inch nominal thickness may be used for shelving, racks, dunnage, scuffboards, floor overlay and similar installations.

(b) Storage in inside storage rooms shall comply with the following:

                          TABLE FL-3 
Automatic                  Total Allowable 
Fire Protection*  Fire     Maximum            Quantities 
Provided        Resistance Floor Area   Gals./sq. ft./floor area 
yes               2-hour     500 sq. ft.         10 
no                2-hour     500 sq. ft.          4 
yes               1-hour     150 sq. ft.          5 
no                1-hour     150 sq. ft.          2 

* Fire protection system shall be sprinkler, water spray, carbon dioxide, dry chemical, halon or other approved system.

(1) Electrical wiring and equipment located in inside storage rooms used for Class I liquids shall be approved for Class I, Division 2 Locations; for Class II and Class III liquids, shall be approved for general use.

(2) Every inside storage room shall be provided with either a gravity or a continuous mechanical exhaust ventilation system. Mechanical ventilation shall be used if Class I liquids are dispensed within the room.

(A) Exhaust air shall be taken from a point near a wall on one side of the room and within 12 inches of the floor with one or more make-up air inlets located on the opposite side of the room within 12 inches from the floor. The location of both the exhaust and inlet air openings shall be arranged to provide, as far as practicable, air movements across all portions of the floor to prevent accumulation of flammable vapors. Exhaust from the room shall be directly to the exterior of the building. If ducts are used they shall not be used for any other purpose and shall comply with the Standard for the Installation of Blower and Exhaust Systems for Dust, Stock and Vapor Removal or Conveying, NFPA No. 91-1973 (ANSI Z33.1). If make-up air to a mechanical system is taken from within the building, the opening shall be equipped with an approved fire door or damper, as required in the Standard for the Installation of Blower and Exhaust Systems, for Dust, Stock and Vapor Removal or Conveying, NFPA 91-1973 (ANSI Z33.1). For gravity systems, the make-up air shall be supplied from outside the building.

(B) Mechanical ventilation systems shall provide at least one cubic foot per minute of exhaust per square foot of floor area, but not less than 150 CFM. (Title 24, T8-5534)


1. Amendment filed 7-16-76; effective thirtieth day thereafter (Register 76, No. 29).

2. Amendment of subsection (b)(1) filed 12-19-78; effective thirtieth day thereafter (Register 79, No. 1).

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