Using and Storing Flammable Liquids

As part of your employment, you may be exposed to flammable liquids on a daily basis, including gasoline, diesel fuel, and many other common products, such as solvents, thinners, cleaners, adhesives, paints, waxes, and polishes. If used or stored improperly, these types of liquids can cause serious injury or death.

To understand the dangers of flammables, remember that it’s the vapor that burns, not the liquid. For instance, an explosion can occur when a worker drains a gas tank and begins repairs involving welding or brazing on the tank. Although the tank may be empty, it contains gasoline vapors. If the vapor concentration is within the explosive range and a source of ignition is introduced, an explosion can easily occur.

Categories
Flammable liquid is any liquid having a flashpoint at or below 199.4°F. Flammable liquids are divided into four categories:

1. Class I – liquids having flashpoints below 73.4°F and having a boiling point at or below 95°F
2. Class II – liquids having flashpoints below 73.4°F and having a boiling point above 95°F
3. Class III – liquids having flashpoints at or above 73.4°F and at or below 140°F
4. Class IV – liquids having flashpoints above 140°F and at or below 199.4°F

General Safety Rules
The following work practices must be followed when handling flammable and combustible liquids:

• Keep open flames or other ignition sources at least 25 feet away from Class I flammable liquids and vapor paths.
• All containers must be properly labeled or marked with the complete chemical name.
• Don’t store flammable liquid containers next to exits, aisles, stairways, or doors, even briefly. Flammable containers should not be placed where they can interfere with the exit from an area or building in an emergency.
• Dispense flammable and combustible liquids with an approved pump or metal self-closing faucet.
• Keep the flammable liquids separated from oxygen tanks and other oxidizers by a fire barrier or by 25 feet.
• Do not transfer liquid unless a staff member trained to stop the transfer in the event of a spill is present.
• When transferring flammable liquids from one container to another, the two containers must be connected by a conducting wire and one container must be grounded.
• Remember that welding, flame cutting, soldering, and other flame-, heat-, or spark-producing work is not allowed within 25 feet of liquid use and storage areas.
• Never smoke in combustible and flammable liquids storage and handling areas or within a 25-foot radius.
• Always maintain access to fire extinguishers and other emergency response equipment. At least one fire extinguisher must be located within 10 feet of any flammable and/or combustible liquid storage area and within 50 feet of a flammable liquid use area.

Indoor Storage and Use

• Use of flammable liquids should be limited to that required for the day’s activities and maintenance.
• The quantity of flammable liquids located outside of a flammables storage room or cabinet in any one fire area of a building, shall not exceed 25 gallons of Class I flammable liquids in containers; 120 gallons of Class II, III, or IV flammable liquids in containers; or 660 gallons of Class II, III, or IV flammable liquids in a single portable tank.
• Maximum capacity of storage cabinets: not more than 60 gallons of Class I, II, III, or 120 gallons of Class IV.

Resources
Flammable Liquids (General Industry), 29 CFR 1910.106, Occupational Safety & Health Administration.
Flammable Liquids (Construction), 29 CFR 1926.152, Occupational Safety & Health Administration.