Last Revised: April 25, 2022

Issued 12/2020

All Class I, Class II and Class IIIA flammable liquids in containers 1 gallon and greater must be stored in a flammable liquids storage cabinet (NFPA 30 4.3.1).  Flammable liquids storage cabinets that meet the construction requirements of NFPA 30-4.3.3, or are custom built and tested in accordance with section NFPA 30-4.3.3(a), or meet the requirements of UL 1275 are acceptable.

NFPA 30 states a flammable liquid storage cabinet must be “constructed to limit the internal temperature at the center of the cabinet and 1 inch from the top of the cabinet to 325 degrees F, when subjected to a 10-minute fire test” (30 4.3.3(a)). Therefore, there are specific construction requirements.

For metal cabinets (NFPA 30 4.3.3(b)):

  1. The cabinet, including door(s), must be constructed of 18-guage steel and double-walled.
  2. All joints must be riveted, welded or “made tight by some equally effective means.”
  3. The door must have a three-point latch attachment.
  4. The sill must be at least 2 inches high.

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For wooden cabinets (30 4.3.3(c)):

  1. The cabinet must be constructed with exterior grade plywood that is at least 1 inch thick and does not break down during fire conditions.
  2. All joints must be rabbeted and fastened with screws in 2 directions.
  3. Cabinets with multiple doors must have at least a 1 inch rabbeted overlap.
  4. The sill must be at least 2 inches high.

Flammable liquid storage cabinets do not need to be vented and any vents should be sealed with the bung provided by the manufacturer (4.3.4).  All cabinets must be marked with “FLAMMABLE – KEEP FIRE AWAY” in “conspicuous” lettering (4.3.5).  At Penn, we do not require free-standing cabinets to be vented, but under-hood cabinets may be vented into the hood using vent kits provided by the manufacturer.

There are buildings on campus which have cabinets that do not meet the above requirements but are currently being used as flammable liquid storage cabinets.  These cabinets are often located under the sinks or under fume hoods.  Some examples are shown below:

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Less than 5 gallons (approximately 20 L) of flammable liquids can be stored in these cabinets.  Larger quantities will require the purchase of a flammable liquid storage cabinet.  For purchasing questions, contact us at