【国外标准】 Standard Specification for Excess Flow Valves for Natural Gas Service

This specification covers requirements and test methods for excess flow valves for natural gas piping systems. Tests methods requirements shall determine the performance characteristics of an excess flow valve installed in a straight piece of pipe. Excess flow valves shall conform to specified materials, dimensions, maximum inlet pressure, temperature rating range, and design requirements. It shall be tested with the following performance requirements: trip flow, leak rate, bypass flow, pressure drop, reset parameters, snap acting loads, and cycle testing.1.1 This specification covers requirements and test methods for excess flow valves for use in thermoplastic natural gas piping systems. However, it is expected that excess flow valves manufactured to the requirements of this specification may also be used in other natural gas piping systems.1.2 Excess flow valves covered by this specification are designed for insertion into components for natural gas systems such as pipe, tubing, or fittings in sizes from 1/2 CTS to 2 IPS.1.3 The tests required by this specification are intended to determine the performance characteristics of an excess flow valve installed in a straight piece of pipe. An excess flow valve could possibly be installed in a straight piece of pipe, in a service tee outlet, as part of a mechanical coupling, or in other configurations. The performance characteristics of the excess flow valve may be significantly different for each installed configuration. Users should conduct their own tests to determine the installed performance characteristics or contact the EFV manufacturer for test data for the installed configuration. Additional guidance on selection and installation of excess flow valves is included in Appendix X1.1.4 The tests required by this specification are not intended to be routine quality control tests.1.5 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.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health and environmental practices and determine the applicability of regulatory limitations prior to use.1.7 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.