The ISO 9614-2: Determination of Sound Power levels using sound intensity: Part 2 - measurement by scanning is an international standard for sound power.
The standard is designed to enable sound power measurements in field (and lab) environments where it is difficult to move the device under test (DUT) into a specially designed acoustic environment, or where support equipment prevents use of traditional sound pressure methods.
By measuring sound intensity on a hypothetical surface, the DUT may be isolated from the rest of the acoustic environment. It is therefore possible to measure in an environment where the extraneous noise energy is louder than the DUT.
In the part 2 of ISO 9614-2, each segment is spatially averaged by the scanning method. The procedure involves moving the probe slowly inside the segment plane while measuring.
The standard operates with the two well-defined ISO accuracy grades:
- Engineering grade [LW(A) ± 1.5 dB]
- Survey grade [LW(A) ± 4 dB]
Engineering grade is more time-consuming than the survey grade, but has well-defined uncertainty constraints for each 1/3 octave band, while survey only defines a A-weighted uncertainty.
To guarantee the uncertainty, a several field indicators are defined. Several checks applies to these field indicators. The Nor150 automatically calculated the field indicators and checks if the measurements are valid.