Flammable Liquid

A term used to classify certain liquids as defined by NFPA 30 as a liquid with a closed-cup flash point below 100°F (37.8°C) and Reid vapor pressures not exceeding 40 psia at 100°F (37.8°C). Flammable liquids are called Class I liquids and have three subdivisions as follows:

  • Class IA: Those having flash points below 73°F (22.8°C) and boiling points below 100°F (37.8°C).
  • Class IB: Those having flash points below 73°F (22.8°C) and boiling points at or above 100°F (37.8°C).
  • Class IC: Those having flash points at or above 73°F (22.8°C) but below 100°F (37.8°C).