What’s the difference between flammable and combustible?
If you read the safety literature, you’ve undoubtedly seen warnings about both flammable and combustible liquids and gases. Both types of materials are hazardous. But there are some differences you should be aware of.- For liquids, the difference between flammable and combustible is the flashpoint. This is the lowest temperature at which a material gives off sufficient vapor to ignite. Note that the liquids themselves don’t burn -- the vapor they give off does.
- A combustible liquid has a flashpoint above 100°F.
- A flammable liquid has a flashpoint below 100°F. Thus, these materials are more dangerous.
- The definition of a flammable gas is a little more complicated. For simplicity’s sake, we can say that it is a compressed gas that will ignite under the right circumstances (e.g., pressure conditions). A combustible gas is a gas that will burn when mixed with oxygen and ignited.
What liquids and gases pose fire hazards?
Many liquids and gases used in industrial settings are flammable or combustible. The lists below identify the most common ones:- Flammable and combustible liquids (North Carolina State University)
- Combustible gases (Industry Scientific)