The term flammable liquid means any liquid which gives off flammable vapors (as determined by flashpoint from an open-cup tester, as used for test of burning oils) at or below a temperature of 80 °F. Flammable liquids are referred to by grades as follows:

1. (a) Grade A. Any flammable liquid having a Reid ¹ vapor pressure of 14 pounds or more.
2. (b) Grade B. Any flammable liquid having a Reid ¹ vapor pressure under 14 pounds and over 8 1/2 pounds.
3. (c) Grade C. Any flammable liquid having a Reid ¹ vapor pressure of 8 1/2 pounds or less and a flashpoint of 80 °F. or below.

¹ American Society for Testing Materials Standard D 323 (incorporated by reference, see § 30.01-3), Method of Test for Vapor Pressure of Petroleum Products (Reid Method).

[CGFR 65-50, 30 FR 16657, Dec. 30, 1965, as amended by CGD 73-96, 42 FR 49023, Sept. 26, 1977; USCG-2000-7790, 65 FR 58458, Sept. 29, 2000]