This standard describes a system for the designation of high-intensity discharge lamps@ including compact@ enclosed-arc discharge light sources such as mercury@ metal halide@ high-pressure sodium@ and similar types of lamps. For convenience@ low-pressure sodium lamps@ although technically not high-intensity discharge lamps@ are included with the group.Purpose The purpose of the designation system covered by this standard is to provide an identification code for use in ANSI standards. Some lamp marking requirements are also identified. Guidance is given as to which characteristics are important (key) to assure interchangeability. The lamp characteristic data given by a manufacturer on a High-Intensity Discharge Lamp Designation Request Form become the basis for the assignment of a designation. They have not been approved by the American National Standards Institute (ANSI) and do not constitute an American National Standard. Similarly@ any consolidated listing of assigned designations with associated characteristics does not constitute an American National Standard.