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.