ANSI/ASA S12.43-1997 (R2012)

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 inits 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 asurvey method of measurement for sound sources operating in their normal environments when less-accurate measurements are acceptable.