BS EN 334. Gas pressure regulators for inlet pressure up to 100 bar Gas valves, Flow regulators, Pressure regulators, Working range, Temperature, Performance, Steels, Zinc alloys, Copper alloys, Aluminium alloys, Cast-iron, Non-destructive testing, Strength of materials, Factor of safety, Classification systems, Approval testing, Mechanical testing, Leak tests, Flow measurement, Inspection, Acceptance (approval), Conformity