These are classified according to their closed flash points. Class `A' products having closed flash points below 73ºF (22. 8ºC). Class `B' from 73ºF (22. 8ºC) to 150ºF (65. 6ºC) inclusive, and Class `C' closed flash points above 150ºF (65. 6ºC). (Inst. Pet. Model Code Safe Practice). See also: Petroleum and Tar Products