Safe Storage of Flammable and Combustible Liquids

What Are They?

A flammable or combustible liquid is any chemical volatile enough to create flammable vapors which can ignite if a spark is present. These liquids are subdivided, based on their boiling and flash points, into a hierarchy of hazard classification. All such liquids are required to be labeled, so if the label on the container says "flammable" or "combustible" anywhere on it, then it meets the criteria and must be stored according to the fire code rules.

Treat empty containers the same as partially filled ones; the vapor in an unrinsed container is as flammable as the liquid was. Put the lid back on and store the container in the same location as you did when it was full.

How Much Stuff Can I Have?

If you have more than 10 gallons total, it must be in an approved cabinet.

If you have more than 30 gallons of flammable liquids, it is possible to be over the quantity limit for liquids of a single hazard classification. Contact EH&S for more details on how to determine whether you have too much of a particular variety of flammable liquid.

If you have more than 60 gallons, you must have more than one cabinet for storage.

You may not have more than three flammable liquid storage cabinets in a room.

You may not have more than the maximum of 120 gallons total of all flammable liquid hazard classes in one room.

Where Do I Put Them?

Not near an exit. Do not store flammable liquids near exit doorways, stairways, or in a location that would make it difficult to get out of the room in case of a fire.

On good shelves. Shelving needs to be sturdy, as well as adequately braced and anchored for seismic safety. The shelves also need to be deep enough to comfortably hold what you put on them, and must have a lip or guard to prevent individual containers from being easily displaced.

Not in a basement. This applies in particular to the most hazardous class of flammable liquids, but is a good rule to follow for all of them.

Not in a refrigerator, unless it's a special one designed, rated, and approved for storage of flammables. Standard refrigerators can create sparks during normal operation that may ignite accumulated vapors, resulting in explosions.

In a special cabinet. To meet the requirements of the fire code, a flammable liquid storage cabinet must have:

1. Conspicuous signs on it which read, in large red letters on a contrasting background, FLAMMABLE - KEEP FIRE AWAY.
2. Doors that are well-fitting, self-closing, and equipped with a latch. It's also a very good idea to have a lock hasp fitted to the cabinet for security.
3. A leakproof bottom, and liquid-tight walls to a height of at least two inches up from the bottom of the interior.
4. Approved construction materials and methods. They may be made of either metal or wood, so long as they meet the specifications of the standard.