OSHA Regulations Regarding Flammables in a Cabinet

The Occupational Safety and Health Administration (OSHA) regulates storage of flammable materials in a variety of work environments. Since improper handling and storage of flammable liquids constitutes the leading cause of industrial fires, the agency closely monitors flammable storage requirements. When it comes to storing flammables in cabinets, the federal agency gives specific cabinet construction rules and storage amount limits for flammable liquids and aerosols.

Flammables storage limit

• OSHA regulation 29 CFR 1910.106 provides most of OSHA's rules for dealing with flammable materials stored in cabinets. Section 1910.106(d)(3)(i) limits the maximum capacity of any storage cabinet to 60 gallons of Class I or Class II liquids, or 120 gallons of Class III liquids. OSHA defines a Class I liquid as a liquid with a flashpoint below 100 degrees F, Class II's flashpoint at more than 100 degrees and less than 140 degrees, and Class III liquids come in with flashpoints between 140 degrees and 200 degrees F. While not usually considered a liquid, any aerosol required to be labeled "Flammable" becomes a Class I liquid when it is stored, according to section 1910.106(a)(13).

Cabinet flammable test

• Under OSHA regulation 1910.106(d)(3)(ii), a properly constructed metal fire resistant storage cabinet limits the cabinet's internal temperature to not more than 325 degrees F. during a 10-minute fire test. Joints and seams must remain tight while the door remains closed. The flammable resistant cabinet must display a sign displaying "Flammable---Keep Fire Away."

Metal flammables cabinet

• OSHA gives very specific guidelines for constructing a metal or wooden fire resistant cabinet. Metal cabinets constructed as follows are deemed in compliance, according to regulation 1910.106(d)(3)(ii)(a). Construct the bottom, top, door and sides of the cabinet with at least No. 18 gauge sheet iron, double walled with 1.5 inches of air space. Rivet, weld, or make joints tight by some other effective means. Install a three-point lock on the door, and raise the door sill at least 2 inches above the bottom of the cabinet.

Wooden flammables cabinet

• OSHA also deems wooden cabinets in compliance when constructed to OSHA standard 1910.106(d)(3)(ii)(b). Construct the bottom, sides and top with an approved grade of plywood at least 1 inch thick. The plywood cannot break down or delaminate under fire conditions. Every joint must be rabbeted and fastened in two directions with flathead screws. If the cabinet uses more than two doors, regulations require a rabbeted overlap of at least 1 inch. Mount hinges to not lose holding capacity due to loosening or burning out of the screws during a burn test.

Cabinet storage exception

• A 2003 OSHA interpretation of storage rules provides an exception to the requirement of storing small quantities of flammable liquids in approved containers. When portions of an "industrial plant where the use and handling of flammable or combustible liquids is only incidental to the principal business," OSHA rule at 29 CFR 1910.106(e)(2)(i) allows storage of up to 25 gallons of Class I liquids in containers or 120 gallons of Class I, II and III liquids in a cabinet that does not meet the specifications of a flammable storage cabinet. OSHA provided examples of places where handling flammables is incidental to the principal business as "automobile assembly, construction of electronic equipment, furniture manufacturing, or similar activities."