This document defines the quality for technical grade sulphur hexafluoride (SF6) and complementary gases such as nitrogen (N2) and carbon tetra-fluoride (CF4), for use in electrical equipment. Detection techniques, covering both laboratory and in-situ portable instrumentation, applicable to the analysis of SF6, N2 and CF4 gases prior to the introduction of these gases into the electrical equipment are also described in this document. This document provides some information on sulphur hexafluoride in Annex A and on the environmental effects of SF6 in Annex B. Information about SF6 by-products and the procedure for evaluating the potential effects of SF6 by-products on human health are covered by IEC 60480, their handling and disposal being carried out according to international and local regulations with regard to the impact on the environment. Handling of SF6 and its mixtures is covered by IEC 62271-4. Procedures to determine SF6 leakages are described in IEC 60068-2-17. For the purposes of this document, the complementary gases used in SF6 mixtures will be limited to N2 or CF4.