本文件规定了天然和机械通风中使用的整流罩和屋顶出口的空气动力学和声学特性的测量方法。只有安装在屋顶表面上方的导管上的整流罩和屋顶插座才符合本标准。 关于辅助车罩，只有风扇辅助车罩被本标准所覆盖，其他类型（如注射辅助车罩）暂时不能充分考虑。 本标准的范围不包括辅助罩的辅助风扇提供的“辅助”性能测试

This document specifies methods for measuring the aerodynamic and acoustic characteristics of cowls and roof outlets used in both natural and mechanical ventilation. Only those cowls and roof outlets fitted onto ducts which project above the roof surface are covered by the present standard. Regarding the assisted cowls, only the fan assisted cowls are covered by the present standard, other types (such as injection assisted cowls) being too recent to be adequately considered for the time being. The performance testing of the "assistance" provided by the auxiliary fan of an assisted cowl is excluded for the scope of this standard.