IEC/TR 62271-303:2008 addresses the procedures for safe and environmental compatible handling of SF6 during installation, commissioning, normal and abnormal operations, disposal at the end of life of high voltage switchgear and controlgear. Storage and transportation of SF6 are also covered. These procedures should be regarded as minimum requirements to ensure the safety of personnel working with SF6 and to minimize the SF6 emission to the environment. This first edition of IEC/TR 62271-303 cancels and replaces the first edition of IEC 61634 published in 1995. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: IEC/TR 62271-303 is a major revision of the old IEC 61634. The former sections of IEC 61634 are removed and replaced by the chapters of the CIGRE brochure n. 276. IEC 61634 was issued in 1995 when the focus was on safety. In 2008, safety is a very well known and established concept and the focus is nowadays on the environmental compatibility. SF6 must be kept in a closed cycle and any intentional release must be forbidden. The implementation of the SF6 reuse concept suggested in the CIGRE brochure was updated with the most recent information. Today SF6 can be recovered and reclaimed for either being reused on-site or given back to the gas supplier and reused as raw material for the production of "technical grade SF6". Detailed procedures for appropriate SF6 handling are given together with the description of the state-of-the-art equipments and measuring devices.