Tracked Changes. Manually operated ball valves and closed bottom taper plug valves for gas installations for buildings|Testing conditions, Thermal testing, Steels, Low-temperature testing, Domestic, Dimensions, Seals, Installation, Cast-iron, Instructions for use, Ball valves, Durability, Gas supply, Copper alloys, Endurance testing, Manually-operated devices, Packaging, Size, Torque, Temperature, Torsion testing, Marking, Ratings, Flow measurement, Performance, Test equipment, Joints, Flow rates, Gas valves, Valves, Leak tests, Thickness, Service pressure, Energy supply systems (buildings), Damp-heat tests, Environmental testing, Plug valves, Scratch tests, Bend testing, Environment (working), Classification systems