Flammable Liquid Storage The following precautions should be taken when storing flammable liquids: • • •
Store quantities of flammable liquids greater than approximately 1 quart, or 32 ounces in safety cans. Store combustible liquids either in their original (or other NFPA-and DOT-approved) containers or in safety cans. Grounding and Bonding: When flammable and combustible liquids travel through a pipe or through the air, static charges are accumulated. Grounding and bonding is necessary during the transfer of Class I flammable liquids to prevent a static spark from igniting the flammable vapors. An example of grounding and bonding is illustrated below.
Reference ClassFlashpoint ExamplesClass II> 100° F and < 140° FDiesel fuel, fuel oil, kerosene, motor oilClass IIIA> 140° F and < 200° FFurfural, linseed oil, mineral oil, oil based paintsClass IIIB> 200° FEthylene glycol, glycerine, neatsfoot oil
Flammable liquid: A liquid with a flashpoint below 100° F. Flammable liquids are subdivided into Class IA, IB, or 1C liquids: ClassFlashpointBoiling PointExamplesClass IA<73° F<100° FEthyl ether, heptane, pentane, propylene oxide, vinyl chlorideClass IB<73° F> 100° FAcetone, ethanol, gasoline, isopropyl alcohol, methanol, tolueneClass IC> 73° F& <100° FAll boiling pointsIsobutyl alcohol, mineral spirits, styrene monomer, turpentine, xylene NOTE: Label safety cans with contents and hazard warning information. Safety cans containing flammable or combustible liquid waste must have appropriate waste labels. Place 20-L (5-gallon) and smaller containers of flammable liquids that are not in safety cans into storage cabinets for flammable liquids. Do not vent these cabinets unless they also contain volatile toxics or odoriferous chemicals. Aerosol cans that contain 21% (by volume), or greater, alcohol or petroleum base liquids are considered Class IA flammables. When space allows, store combustible liquids in storage cabinets for flammable liquids. Otherwise, store combustible liquids in their original (or other Department of Transportation-approved) containers.
Part 2 Safety Can: A listed container with a capacity of no more than 5 gallons that has a spring-closing lid and spout cover and is designed to safely relieve internal pressure when exposed to fire. Flammable Storage Cabinet: A "flammable storage cabinet" is a listed storage cabinet designed in accordance with NFPA 30: 4.3.3. Such a cabinet is designed and constructed to limit the internal temperature to no more than 325째 F from the center of the cabinet to within 1 inch of the top of the cabinet when subjected to a 10 minute fire test. Lower Explosive Limit (LEL): The minimum vapor concentration (by percent) in which a liquid can form an ignitable mixture in air is called the "lower explosive limit." Below this limit, vapor concentration is too lean to support combustion. Upper Explosive Limit (UEL): The maximum vapor concentration (by percent) in which a liquid can form an ignitable mixture in air is called the "upper explosive limit." Above this limit, vapor concentration is too rich to support combustion. Explosive Range: The range between the LEL and UEL is the "explosive range." If a source of ignition such as a flame, spark, or static electricity is present, an explosion may occur. This may also be referred to as the "flammable range." The graph below illustrates the explosive range of gasoline.