The term Reid vapor pressure means the vapor pressure of a liquid at a temperature of 100 °F., expressed in pounds per square inch absolute, as determined by the Reid Method as described in the American Society for Testing Materials Standard D 323 (incorporated by reference, see § 30.01-3), Method of Test for Vapor Pressure of Petroleum Products. This Standard is available at Headquarters for reading purposes or it may be purchased from the Society at 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959.