本标准提供了三种方法来测量工作站和其他指定位置所有类型机械和设备的声压级。第一种方法适用于反射面上基本自由场的测量。通常，声压级等于或低于机器运行时的声压级 不包括背景噪音或安装表面以外表面反射的影响。第二种方法适用于正常工作环境中的测量，其中测量中考虑了背景噪声和机器周围表面反射的影响。 第三种方法是 当测量精度较低时，在正常环境中工作的声源的测量方法。

This Standard provides three methods to measure sound pressure levels from all types of machinery and equipment at workstations and other specified positions. The first method applies to measurements in an essentially free field over a reflecting plane. The sound pressure levels are, in general, equal to or lower than those that would occur when the machine is operated in its normal surroundings as the effects of background noise or reflections from surfaces other than the mounting surface are excluded. The second method applies to measurements in normal operating environments where the effects of background noise and reflections from surfaces surrounding the machine are accounted for in the measurements. The third method is a survey method of measurement for sound sources operating in their normal environments when less-accurate measurements are acceptable.