This guide is for the development of specifications for the technical requirements for the design, fabrication, testing, installation, and in-service performance of a high-voltage gas-insulated substation (GIS). This document is issued as a guide for use in compiling procurement specifications for the design, fabrication, testing, installation and in-service performance of high-voltage gas-insulated substation equipment. This guide applies specifically to all types of high-voltage gas-insulated substation equipment rated above 52 kVac. The imperative mode of the language is illustrative of that used in design and procurement specifications. It does not imply that this document is anything other than advisory in its scope. Specifically, this revision will align the text with IEEE Std C37.122(TM) and IEEE Std C37.122.1(TM). This guide is not intended to develop a complete specification for a turnkey project. General terms and conditions forming the commercial part of a specification for a particular project are outside the scope of this document. Revision Standard - Superseded. The development of specifications for the technical requirements for the design, fabrication, testing, installation, and in-service performance of a high-voltage gas-insulated substation (GIS) are covered in this guide.