This part of IEC 62271 applies to the procedures for handling of gases and gas mixtures for insulation and/or switching during installation, commissioning, repair, overhaul, normal and abnormal operations and disposal at the end-of-life of high-voltage switchgear and controlgear. These procedures are regarded as minimum requirements to ensure the reliability of electric power equipment, the safety of personal working with these gases and gas mixtures and to minimize the impact on the environment. Additional requirements could be given or specified in the operating instruction manual of the manufacturer. For each gas or gas mixture, which is known to be used in electric power equipment at the date of the publication of this document, a separate annex describes specifications, handling procedures, safety measures, etc. For gases or gas mixtures not covered by these annexes the electric power equipment manufacturer should provide the information needed, following the structure of these annexes. Such gases or gas mixtures should also be described in a next edition or in amendments to this edition. NOTE 1 For the use of this document, high-voltage (HV) is defined as the rated voltage above 1 000 V. However, the term medium-voltage (MV) is commonly used for distribution systems with voltages above 1 kV and generally applied up to and including 52 kV. NOTE 2 Throughout this standard, the term "pressure" stands for "absolute pressure". NOTE 3 Reference is also made to (Cigré Brochure 802, 2020). NOTE 4 For further details on gases, e.g. ecotoxicology, also refer to the chemical database ECHA (www.echa.europa.eu), which takes the actual volume band into consideration. NOTE 5 When reference to circuit-breakers is made, only gas circuit-breakers are of interest. When vacuum circuit breakers are of interest, they are explicitly mentioned.