Flammable and Combustible Liquids*

*Definitions are provided from the NFPA 30: Flammable and Combustible Liquids Code, 2003 (Chapter I, Section 1.7 "Definition and Classification of Liquids")

Liquid:

Any material that has a fluidity greater than that of 300 penetration asphalt when tested in accordance with ASTM D5--06e1 "Test for Penetration for Bituminous Materials". (NFPA 30: Section 1.7.2.3)

Classification of Liquids:

Any liquid within the scope of this code and subject to the requirements of this code shall be known generally as either a flammable liquid or a combustible liquid and shall be defined and classified in accordance with this subsection. (NFPA 30: Chapter I, Section 1.7.3)

Combustible Liquid:

Any liquid that has a closed-cup flash point at or above 100°F (37.8°C), as determined by the test procedures and apparatus set forth in 1.7.4. (NFPA 30, Chapter I, Section 1.7.3.1)

Combustible liquids are classified as Class II or Class IIA as follows:

  1. Class II Liquid -- Any liquid that has a flash point at or above 100°F (37.8°C) and below 140°F (60°C);
  2. Class IIIA Liquid -- Any liquid that has a flash point at or above 140°F (60°C), but below 200°F (93°C);
  3. Class IIIB Liquid -- Any liquid that has a flash point at or above 200°F (93°C).

Flammable Liquid:

Any liquid that has a closed-cup flash point below 100°F (37.8°C), as determined by the test procedures and apparatus set forth in 1.7.4. (NFPA 30: Chapter I, Section 1.7.3.2)

Flammable liquids are classified as Class I as follows:

Class I Liquid: Any liquid that has a closed-cup flash point below 100°F (37.8°C) and a Reid vapor pressure not exceeding 40 psia (2068.6 mm Hg) at 100°F (37.8°C), as determined by ASTM D 323, "Standard Method of Test for Vapor Pressure of Petroleum Products" (Reid Method) Class I liquids are further classified as follows:

  1. Class IA Liquids: -- Those liquids that have flash points below 73°F (22.8°C) and boiling points below 100°F (37.8°C)
  2. Class IB Liquids -- Those liquids that have flash points below 73°F (22.8°C) and boiling points at or above 100°F (37.8°C).
  3. Class IC -- Those liquids that have flash points at or above 73°F (22.8°C), but below 100°F (37.8°C).

Updated December 6, 2006 by SAK