OSHA caps what a single flammable storage cabinet may hold, and caps how many cabinets sit in one fire area. Enter the volume you store by liquid class and this calculator returns the number of cabinets required under 29 CFR 1910.106(d)(3) — and flags the point where a cabinet stops being enough.
What is the flammable cabinet limit?
Short answer: a single safety cabinet may hold 60 gallons of Class I or Class II liquids, or 120 gallons of Class III liquids. The 60-gallon figure is an aggregate — a cabinet cannot hold 60 gallons of Class I and another 60 of Class II. The full standard is worked through on OSHA flammable cabinet requirements.
| Liquid class | Flash point | Cabinet limit |
|---|---|---|
| Class I | Below 100°F | 60 gallons combined for Class I + Class II |
| Class II | 100°F to below 140°F | |
| Class III | At or above 140°F | 120 gallons for Class III alone |
How many cabinets can one fire area have?
Not more than three safety cabinets in a single fire area. Once your inventory exceeds what three cabinets hold, the storage moves into an inside liquid storage room built to 29 CFR 1910.106(d)(5) — which brings fire-resistance ratings of 2 hours for rooms over 150 square feet and 1 hour for smaller rooms.
What counts as an approved cabinet?
A cabinet must either be UL 1275 listed or FM Approved, or meet the construction specification in 1910.106(d)(3)(ii): double-wall metal with at least 1.5 inches of air space, a 2-inch raised sill, and a self-closing, latching door. A cabinet that no longer self-closes and latches is not a compliant cabinet, whatever the label says.
Frequently Asked Questions
How many gallons can a flammable storage cabinet hold?
A single safety cabinet is limited to 60 gallons of Class I or Class II liquids, or 120 gallons of Class III liquids, under 29 CFR 1910.106(d)(3).
Can a cabinet hold 60 gallons of Class I and 60 gallons of Class II?
No. The 60-gallon limit is an aggregate across Class I and Class II together. The combined total of both classes in one cabinet cannot exceed 60 gallons.
How many flammable cabinets are allowed in one fire area?
Not more than three safety cabinets in a single fire area. Beyond that, storage moves into an inside liquid storage room meeting 29 CFR 1910.106(d)(5).
What makes a flammable cabinet OSHA compliant?
The cabinet must be UL 1275 listed or FM Approved, or meet the construction specification in 1910.106(d)(3)(ii): double-wall metal with at least 1.5 inches of air space, a 2-inch raised sill, and a self-closing, latching door.
What are the OSHA flammable liquid classes?
Class I liquids have a flash point below 100°F, Class II from 100°F to below 140°F, and Class III at or above 140°F. The class determines both the cabinet limit and the quantity that may be kept outside a cabinet.
Do I need a fire extinguisher near flammable storage?
Storage areas for Class IB and IC liquids require a Class B fire extinguisher within 50 feet, per 29 CFR 1910.157(d)(2).
This calculator applies the cabinet limits in 29 CFR 1910.106(d)(3) to the volumes you enter. It does not assess exempt quantities kept outside cabinets, inside storage room design, dispensing, bonding and grounding, or local fire code, which may be stricter.
Related: spill containment and fire extinguishers.