ISO/IEC Guide 28:2004 gives general guidelines for a specific product certification system.
It is applicable to a third-party product certification system for determining the conformity of a product with specified requirements through initial testing of samples of the product, assessment and surveillance of the involved quality system, and surveillance by testing of product samples taken from the factory or the open market, or both. ISO/IEC Guide 28:2004 addresses conditions for use of a mark of conformity and conditions for granting a certificate of conformity.