Storing Flammable and Combustible Liquids

Flash point is the lowest temperature at which a liquid gives off enough vapor to ignite. It's how these liquids are split:

• Flammable liquid — flash point below 100°F (37.8°C). Gasoline flashes around −45°F, so it's giving off ignitable vapor at any job-site temperature.
• Combustible liquid — flash point at or above 100°F (37.8°C), like diesel and many oils. Harder to light, but still burns once it's hot enough.

Either way, treat the vapor as the hazard. Keep containers closed, keep the area ventilated, and keep ignition sources back.

Store and carry these liquids only in approved containers. A safety can is self-closing, holds no more than 5 gallons, and has a flame arrester and a spring-loaded lid that relieves pressure and snuffs flashback.

Keep liquids in their original labeled containers or a properly labeled safety can. No open buckets, no unmarked jugs, no soda bottles — an unlabeled container is how someone pours the wrong thing or lights it off.

Don't let quantities build up in the work area. OSHA sets limits:

• No more than 25 gallons of flammable liquids stored in containers outside of an approved storage cabinet in any one room.
• A flammable storage cabinet holds no more than 60 gallons of Category 1, 2, or 3 flammable liquids, or 120 gallons of Category 4 combustible liquids.
• No more than three storage cabinets grouped in one area.
• Cabinets are labeled in conspicuous lettering: "Flammable — Keep Fire Away."

Store away from exits, stairways, and ignition sources, out of direct sun, and where a spill can be contained.

Pouring liquid between metal containers builds up static — and one static spark in fuel vapor is all it takes. When you transfer flammable liquids, bond the containers together and ground them so the charge can't jump.

Post "No Smoking or Open Flame" signs at storage and dispensing areas and mean it — no smoking, no hot work, no running engines nearby. Clean up spills right away and get soaked rags into a covered metal container.