How to Store Flammable Liquids

Storage, handling and use of flammable and combustible liquids require special attention. Avoid injury and potential losses by taking proactive steps to store your flammable liquids safely. We’ve highlighted some important information about how to meet the National Fire Protection Association codes for storing flammable liquids.

These liquids don’t burn or explode by themselves — however, heavier-than-air vapors from liquid evaporation tend to settle on the floor. These vapors can flow along the floor for long distances, ignite at some remote point and flash back. This is one reason why specially designed storage cabinets and rooms must be used for flammable liquids, such as paints, solvents and thinners.

According to the National Fire Protection Association (NFPA) Code 30, up to 15 gallons of flammable liquids must be stored in safety cans. Amounts from 15 to 60 gallons must be stored in a standard flammable liquid storage cabinet meeting the specifications of the NFPA Code 30. Flammable liquid storage cabinets, which can be found in any safety equipment/supply store, must adhere to the following guidelines:

• Do not store more than 60 gallons of flammable liquid per small containers in a flammable liquid storage cabinet.
• Cabinets must be Underwriter laboratory (UL) approved.
• The cabinet top, doors and sides must be made of 18 U.S. gauge sheet steel and double walled with tight joints.
• The door must have a three point latch with a sill raised to at least 2 inches above the bottom of the cabinet to retain spilled liquids.

Also, according to the NFPA Code 30, flammable liquids with flash points lower than 73 degrees F and in quantities greater than 60 gallons must be stored in a specially designed storage room. This room is designed to protect flammable liquids from fire exposures in other portions of the building and to contain fires that originate within the room.

Flammable liquid storage rooms must have the following features:

• Ideally, the room must be detached from the main building. The next best option is an attached room separated by a blank wall.
• The room must be ventilated for removal of vapors. Ventilation must be either a gravity or mechanical exhaust ventilation system. The ventilation must be continuous, 24 hours a day, and a complete air change within the room must occur at least six times per hour. A gravity system has openings present at the top and bottom of the room which allow air to circulate in from the top and out at the bottom.
• Explosion-proof wiring is required. Class I, Division 2 wiring is required for rooms that store sealed containers. If dispensing or mixing takes place, the wiring must be Class I, Division 1.
• Ceilings, floors and walls must have a fire resistance rating of two hours. The door must be Class B, self-closing, and be fire rated for 1½ hours.
• Floors and wall edges that join the floor must be liquid tight.
• Raised sills of at least 4 inches in height must be present to prevent liquid from flowing to adjoining areas. A permissible alternative is an open-grated trench, which drains to a safe location, across the width of the opening inside of the room.