Flammable liquids

Scope

OSHA’s flammable liquids requirements apply to employers who have employees who use or are exposed to flammable liquids. Depending on the type of work yielding the exposure, the quantities, and other factors, there are varying requirements.

Regulatory citations

• 29 CFR 1910.106 — Flammable liquids

Key definitions

• Aerosol: A material which is dispensed from its container as a mist, spray, or foam by a propellant under pressure.
• Approved: Unless otherwise indicated, approved, or listed by a nationally recognized testing laboratory.
• Boiling point: The boiling point of a liquid at a pressure of 14.7 pounds per square inch absolute (p.s.i.a.) (760 mm.).
• Fire area: An area of a building separated from the remainder of the building by construction having a fire resistance of at least 1 hour and having all communicating openings properly protected by an assembly having a fire resistance rating of at least 1 hour.
• Flammable liquid: Any liquid having a flashpoint at or below 199.4 °F (93 °C). Flammable liquids are divided into “categories” (they used to be divided into “classes,” but OSHA revised the standard in May 2012). The categories are:
  • Category 1 include liquids having flashpoints below 73.4 °F (23 °C) and having a boiling point at or below 95 °F (35 °C).
  • Category 2 include liquids having flashpoints below 73.4 °F (23 °C) and having a boiling point above 95 °F (35 °C).
  • Category 3 include liquids having flashpoints at or above 73.4 °F (23 °C) and at or below 140 °F (60 °C). When a Category 3 liquid with a flashpoint at or above 100 °F (37.8 °C) is heated for use to within 30 °F (16.7 °C) of its flashpoint, it must be handled in accordance with the requirements for a Category 3 liquid with a flashpoint below 100 °F (37.8 °C).
  • Category 4 include liquids having flashpoints above 140 °F (60 °C) and at or below 199.4 °F (93 °C). When a Category 4 flammable liquid is heated for use to within 30 °F (16.7 °C) of its flashpoint, it must be handled in accordance with the requirements for a Category 3 liquid with a flashpoint at or above 100 °F (37.8 °C).
  • When liquid with a flashpoint greater than 199.4 °F (93 °C) is heated for use to within 30 °F (16.7 °C) of its flashpoint, it must be handled in accordance with the requirements for a Category 4 flammable liquid.
• Flash point: The lowest temperature at which the vapor of a substance will catch on fire. This measure provides an indication of how flammable a substance is.
• Portable tank: A closed container having a liquid capacity over 60 U.S. gallons and not intended for fixed installation.
• Safety can: An approved container, of not more than 5 gallons capacity, having a spring-closing lid and spout cover and so designed that it will safely relieve internal pressure when subjected to fire exposure.
• Vapor pressure: The pressure, measured in pounds per square inch (absolute) exerted by a volatile liquid as determined by the “Standard Method of Test for Vapor Pressure of Petroleum Products (Reid Method),” American Society for Testing and Materials ASTM D323-68, which is incorporated by reference as specified in 1910.6.
• Ventilation: For the prevention of fire and explosion. It is considered adequate if it is sufficient to prevent accumulation of significant quantities of vapor-air mixtures in concentration over one-fourth of the lower flammable limit.

Summary of requirements

In general, covered employees are required to:

• Properly design and install flammable liquid storage tanks.
• Properly design and install drainage, dikes, and walls for aboveground tanks.
• Use only approved containers for flammable liquids.
• Use only approved flammable storage cabinets, and do not exceed storage amount limitations.
• Follow the construction requirements for inside storage rooms.
• Follow flammable liquid storage amount limitations for warehouses or storage buildings.
• Follow flammable liquid storage amount limitations outside of buildings.
• Follow the precautions to prevent the ignition of flammable vapors.
• Follow the requirements for providing appropriate firefighting equipment in areas where flammable liquids are stored and used.
• Employ the required maintenance and operating practices to control leakage and prevent the accidental escape of flammable liquids.