BS EN ISO 28921-2:2017规定了低温隔离阀的型式试验要求 用于验证阀门在-50°C至-196°C低温下性能的应用。注:标称尺寸（DN）、标称管道尺寸（NPS）、标称压力（PN）和等级包含在 ISO 28921-1。ISO 28921的本部分不评估阀门执行机构，除非它们是阀门的组成部分。测试期间的阀门可以手动操作，也可以在测试期间使用致动器。效果 如果安装了致动器，则应特别考虑试验期间冷气体蒸汽的泄漏 直接在试验台上方，冷气体吞没致动器。 ISO 28921的本部分不适用于按照 ISO 21011，用于低温容器。交叉引用:ISO 5208ISO 28921-1ASME B31。3EN 13480-2ISO 6002ISO 6708ISO 7121ISO 7268ISO 10434ISO 10497ISO 10631ISO 12149ISO 14313ISO 15761ISO 17292ISO 21011ISO 23208ASME B16。34包括以下内容:勘误表，2017年3月

BS EN ISO 28921-2:2017 specifies requirements for the type testing of isolating valves for low-temperature applications to verify the performance of valves at a low temperature from - 50 °C down to - 196 °C.NOTE Nominal sizes (DN), nominal pipe sizes (NPS), nominal pressure (PN) and Classes are covered in ISO 28921-1.This part of ISO 28921 does not evaluate valve actuators unless they are integral part of the valve.Valves during testing can be operated manually or an actuator can be used during the testing. The effect of cold gas vapours during testing is taken into consideration in particular if the actuator is mounted directly over the test stand with the cold gases engulfing the actuator.This part of ISO 28921 does not apply to valves for cryogenic services, designed in accordance with ISO 21011, used with cryogenic vessels.Cross References:ISO 5208ISO 28921-1ASME B31.3EN 13480-2ISO 6002ISO 6708ISO 7121ISO 7268ISO 10434ISO 10497ISO 10631ISO 12149ISO 14313ISO 15761ISO 17292ISO 21011ISO 23208ASME B16.34Incorporates the following:Corrigendum, March 2017