Any liquid that has a closed-cup flash point at or above 100ºF (37.8ºC), as determined by the test procedures defined in NFPA 30. Combustible liquids are classified as Class II or Class III as follows:
- Class II Liquid. Any liquid that has a flash point at or above 100ºF (37.8ºC) and below 140ºF (60ºC).
- Class IIIA. Any liquid that has a flash point at or above 140ºF (60ºC), but below 200ºF (93ºC).
- Class IIIB. Any liquid that has a flash point at or above 200ºF (93ºC).
(NFPA 30)