ANSI/（NFPA）T3的修订。21.8-1990（R1997）。1适用范围和领域本标准将用作ISO 12238的替代品，ISO 12238被认为是首选方法。本标准旨在:包括定义、确定和报告电动或气动方向控制阀响应时间的标准化程序。结果仅适用于在进行试验时的压力和温度下的压缩空气。尽管所含方法可适用于其他气体、压力或温度，但这些情况不在本标准范围内--建立响应时间的标准定义--通过向制造商和用户提供电动或气动气动方向控制阀动态性能测量的标准化程序，促进气动流体动力系统的改进。 --建立传达这些结果的标准方法。

Revision of ANSI/(NFPA)T3.21.8-1990 (R1997).1 Scope and field of applicationThis standard is to be used as an alternative to ISO 12238, which is recognized as the preferred method.This standard is intended:--to include a standardized procedure for defining, determining and reporting the response time of electrically or pneumatically operated pneumatic directional control valves. The results are applicable only to compressed air at the pressure and temperature at which the test was conducted. Although the method contained can be applied to other gases, pressures or temperatures, these cases are outside the scope of this standard.--to establish a standard definition of response time.--to promote improved pneumatic fluid power systems by providing manufacturers and users with a standardized procedure for measurement of the dynamic performance of electrically or pneumatically operated pneumatic directional control valves.--to establish a standard means of communicating these results.