This standard specifies the characteristics of high-pressure sodium vapor lamps necessary to ensure interchangeability and safety together with test conditions and procedures. The recommendations relate only to type testing. The standard specifies the lamp dimensions@ electrical characteristics for lamp starting and operation together with information for ballast@ ignitor and luminaire design purposes. The requirements dealing with the lamp starting test and associated information for ballast/ignitor design are different depending on the practice of the country in which the lamp type was originally developed. NOTE The requirements and tolerances permitted by this standard correspond to testing of a type test sample submitted by the manufacturer for that purpose. In principle@ this type test sample should consist of units having characteristics typical of the manufacturer's production and being as close to the production centre point values as possible. It may be expected with the tolerances given in the standard that product manufactured in accordance with the type test sample will comply with the standard for the majority of production. Due to the production spread however@ it is inevitable that there will sometimes be products outside the specified tolerances. For guidance on sampling plans and procedures for inspection by attributes@ see IEC 60410.