【国外标准】 Standard Specification for Automatic Shut-Off Valves (Also Known as Excess Flow Valves, EFV) for Air or Nitrogen Service

This specification covers self-contained automatic shutoff valves (also known as excess flow valves) for air or nitrogen service. They are intended to be installed as safety devices to quickly and automatically shut off flow under certain excess flow conditions caused by a downstream failure or casualty, such as a hose rupture. Automatic shut-off valves shall be of the following types, styles, sizes, pressure ratings, and end connections: Types I and II; Styles 1 and 2. Each automatic shut-off valve must pass the following tests: visual examination; hydrostatic shell test; seal tightness test; external leakage test; and set-point test.1.1 This specification covers self-contained automatic shut-off valves (also known as excess flow valves) for air or nitrogen service. They are intended to be installed as safety devices to quickly and automatically shut off flow under certain excess flow conditions caused by a downstream failure or casualty, such as a hose rupture.1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.