SAFETY SOLUTIONS: OSHA's Flammable & Combustible Liquids
Each year fires destroy many places of business and
homes because flammable and combustible liquids
were not properly stored.
Flammable liquids are used in hundreds of thousands
of processes and they're used safely every day. The
answer to flammable liquid safety is to follow company safety
procedures and work rules and, of course, the information
provided for the manufacturer. Each employee holds
the key to safety when working with flammable liquids.
Knowledge is the first step, but putting that information to
work for you makes the difference in safety.
Proper flammable material storage is essential for fire prevention.
Flammable storage locations can range from purpose-
built building or storerooms to NFPA rated flammable
storage cabinets. All flammable storage cabinets must be
vented to the outside when they are installed. OSHA regulations
for this hazard can be found in 29 CFR 1910.101 to
1910.126. and can be read online at www.osha.gov.
Here are some answers to basic questions:
Q: Why store flammable and combustible liquids inside a
flammable liquid storage cabinet?
A: To protect flammable liquids against flash fire, to prevent
the containers from building excessive internal pressure,
and to contain spilled flammable liquids that can further
Q: Is my existing flammable liquid storage cabinet
A: Cabinets must be Underwriter Laboratories (U.L.)
(1275) listed or Factory Mutual (F.M.) approved, which is
indicated by a permanent manufacture’s label on the cabinet.
Alternatively, cabinets must be constructed in accordance
with the following:
Regardless of wood or metal cabinet, each cabinet shall
have the following:
- Unlisted metal cabinets shall be of steel having a thickness
of not less than 0.044" (18 gauge). The cabinet,
including the door, shall be double walled with 1-1/2" airspace
between the walls. Joints shall be riveted or welded
and shall be tight fitting. Doors shall be well fitted, self-closing
and equipped with a latching device, OR,
- Unlisted wooden cabinets, including doors, shall be
constructed of not less than 1” exterior grade plywood.
Joints shall be rabbited and shall be fastened in two directions
with wood screws. Door hinges shall be of steel or
brass. Cabinet shall be painted with an intumescent-type
paint. Doors shall be well fitted, self-closing and equipped
with a three point latch.
Q: What is the maximum quantity of flammable and combustible
liquids that I can store inside a single storage cabinet?
- The bottom of the cabinet shall be liquid-tight to a
height of at least 2".
The door shall be well fitted, self-closing and equipped
with a three point latch.
It should bear a conspicuous label on contrasting
background which reads, “FLAMMABLE – KEEP FIRE
AWAY” on the front.
A: Cabinets are available in different sizes ranging from
4-gallon (15-liter) to 120 gallon (454-liter) capacity.
However, per regulations, no more than 60 gallons of Class
I-A flammable liquids may be stored inside a single cabinet.
Class I-A flammable liquid is liquid having a closed cup flash
point below 73°F and boiling point below 100OF.
Q: Should the flammable liquid storage cabinet be vented?
A: When used for storage of closed containers, a flammable
liquid storage cabinet is not required to be vented for
fire protection purposes. Vent openings must be sealed with
the bungs supplied with the cabinet or with bungs specified
by the cabinet manufacturer. If venting is required for other
reasons such as personnel exposure or dispensing operations
within the cabinet, then venting using the opening
provided by the manufacturer shall be provided with metallic
vent pipe directly to outdoors or to the fume hood
exhaust duct in a manner that is acceptable to the local Fire
Proper venting practices: remove steel bungs from the
factory furnished vent ports; connect metal vent pipe directly
to the lower vent port since hydrocarbon vapors are usually
heavier than air; inspect the upper vent port to ensure
the flame arrestor is installed. The upper vent port with the
flame arrestor will provide make up air for efficient purging.
Do not cut or drill into the exterior of a cabinet for vent connection.
Q: Should the flammable liquid storage cabinet be
A: No, unless you are dispensing from one of the containers
when it is sitting inside the cabinet.
Q: Who makes flammable liquid storage cabinets and
where can I purchase one?
A: Cabinets can be purchased from lab equipment supply
companies or safety equipment supply companies.
A special thank you to OSHA and to the University of
California Berkeley for permission to use some of their information
from their fact sheet.
For more information, click on the author link at the top of the page.