Applies to the design, construction and testing of valves, water gauges, and other fittings, and specifically refers to safety valves, liquid relief valves, water gauges, blow-down valves and high and low water alarms. These valves and fittings are intended for use on land boilers, unfired pressure vessels and their associated equipment. The specification does not purport to cover the selection, operation, or application of valves and fittings, such provisions being appropriately dealt with in the standard applying to the equipment to which the valves and fittings are to be connected.