This guide covers the technical requirements for the design, fabrication, testing, installation, and in-service performance of a gas-insulated substation (GIS). The supplier should furnish all equipment and material necessary to provide the complete GIS as shown on the functional one-line diagram, which may consist of circuit breakers (CB), disconnect switches (DS), maintenance ground switches (MGS), fast-acting ground switches (FGS), voltage transformers (VT), current transformers (CT), SF6-to-air bushings, SF6-to-cable termination, buses, cable termination enclosures, transformer or reactor bushing enclosures, enclosed surge arresters, elbows, bellows, controls, cables for control, protection and metering, density monitors, platforms, special tools, and SF6 gas for initial filling. All equipment and material shall be prefabricated, factory assembled, tested, and shipped in the largest practical assemblies. Assembled equipment should be capable of withstanding electrical, mechanical, and thermal ratings of the specified system. All joints and connections should be able to withstand the forces of expansion, vibration, contraction, and specified seismic requirements without deformation, malfunction, or leakage. Equipment shall be capable of withstanding the specified outdoor or indoor environment. Optimized arrangements, shown in annex A, are required to reduce installation time, provide ease of operation, minimize maintenance and repair prices, and facilitate future additions as described in the specifications. The user should identify space or area limitations for the GIS, driveway access, and any overhead clearance restrictions. Final arrangement shall be as mutually agreed to between the user and the supplier. Field assembly maintenance, cost of operation, and capitalized cost of maintenance during equipment life will be considered in bid evaluations. To elicit a complete and uniform response from each bidder, proposal data is provided in clause 7.