This guide provides information regarding the planning, specification, testing, installation, operation, and maintenance of indoor gas-insulated substations (GIS) and equipment. This document does not contain a purpose clause. New IEEE Standard - Inactive-Reserved. The technical requirements for the design, fabrication, testing, and installation of indoor gas-insulated substations (GIS) 1 kV up to 52 kV are covered. Parameters to be supplied by the purchaser are suggested and technical requirements for the design, fabrication, testing, and installations to be furnished by the manufacturer are established.