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A flammable liquid has a flashpoint below 100° F. A flammable liquid itself does not burn; it is the vapor from the liquid that burns. The rate at which a liquid produces flammable vapors depends on its vapor pressure. The vaporization rate increases as the temperature increases; therefore, a flammable liquid is more hazardous at elevated temperatures than at normal temperatures.

12.5.1 Hazards of Flammable Liquids

A primary concern in the lab is to reduce the amount of fuel available to support a fire if one were to start. Even a small amount of flammable liquid involved in a fire could cause it to spread dramatically.

The following requirements reflect Seattle Fire Department regulations. Enforced by the Fire Department and EH&S, they are designed to restrict the distribution and volumes of flammable solvents to a safe level. See also Section 12.15, Solvents.

12.5.2 Handling Procedures for Flammable Liquids

Keep flammable liquids away from heat and direct sunlight.

DO NOT heat flammable liquids directly over a burner or an electrical device that can generate sparks, or has a surface temperature in excess of that which might cause auto-ignition.

12.5.3 Storage of Flammable Liquids: Volume Limits in Labs

The Seattle Fire Department fire codes are stringent. The code limits the quantities of hazardous materials allowed in each building. A control area or building may not store more than 240 gallons of Class IB flammables (ethanol, methanol, acetonitrile, xylene, acetone, butanol, isopropanol and organic scintillation cocktail). This limits each lab to approximately 13 gallons of class IB flammables.

The maximum amount of flammable liquids not stored in a flammable storage cabinet is 5 gallons per lab. Therefore:

  1. Storage of flammable materials outside of flammable storage cabinets should be limited as much as possible or eliminated.
  2. If safety cans do not fit in flammable storage cabinets, the lab should make arrangements to purchase a smaller safety can.

If glass or plastic containers must be used for solvents with flashpoints under 100°F, they must be of no more than one-gallon capacity.

Flammable liquids and solutions that must be stored in a cool environment must be stored in a flammable-storage refrigerator or freezer. Stock supplies of flammable liquids shall not be stored in cold rooms, which are neither vented nor explosion-proof.

12.5.4 Refrigeration of Flammable Liquids

Because flammable solvents have very low flashpoints and flammable limits (lowest vapor concentration that can be ignited with a spark), a normal refrigerator does not provide safe storage for them. Ordinary refrigerators commonly have many sources of ignition (e.g., thermostat, interior light, light switch on the door, defrost heater, defrost control switch, the compressor unit, and the fan). The ignition sources have ignited trapped vapors from poorly sealed or broken containers and caused harmful lab explosions.

12.5.5 Disposal of Flammable Liquids

See Chapter VI, Hazardous Waste Directory, Section 6, Sewer Limits. Most flammable materials will need to be labeled for collection by EH&S.

12.5.6 Emergency Response: Exposure

  • Skin: immediately remove affected clothing and flush tissue with copious amounts of water for 15 minutes.

  • Eye contact: rinse eyes with copious amounts of water for 15 minutes. Hold lids open while rinsing. Seek medical evaluation.

Complete an Accident-Illness Report Form as soon as possible and mail to EH&S at J3-200.

12.5.7 Emergency Response: Spills

While wearing safety goggles, gloves, and a lab coat, you can absorb a small spill with a universal absorbent. For large spills (>200 ml), call EH&S for clean-up.