A term used to classify certain liquids that will burn on the basis of flash points. The National Fire Protection Association (NFPA) defines a combustible liquid as any liquid that has a closed-cup flash point above 100°F (37.8°C) (NFPA 30). There are three subclasses, as follows:
- Class II liquids have flash points at or above 100°F (37.8°C) but below 140°F (60°C)
- Class III liquids are subdivided into two additional subclasses:
- Class IIIA: Those having flash points at or above 140°F (60°C) but below 200°F (93.4°C).
- Class IIIB: Those having flash points at or above 200°F (93.4°C).
The Department of Transportation (DOT) defines “combustible liquids” as those having flash points of not more than 141°F (60.5°C) and below 200°F (93.4°C).