Determining sound power of fixed machinery: how to overcome the hassles by using a reference sound power source
Acoustically complex measurements
Smaller infrastructure independent machinery can be brought into specialized measurements chambers to measure their total sound power emission. However, for larger machines or fixed infrastructure dependent machines this is not possible. In this case, on-site measurements in their natural conditions is required in which case the measurement conditions can become acoustically complex.
Efficient sound power determination
The reference sound power method is interesting for on-site determination, because it is fast, has low complexity and does not require elaborate equipment.
There is a clear ISO standard 3747 to guide the measurement and processing and provides estimates of worst case accuracy.
Another on-site alternative method includes detailed sound intensity scanning and/or inverse techniques which allow measurement of the sound power emission with
more details. These methods however include a significant time investment and complexity.
Off-site testing is possible by brining equipment into an acoustic lab for a straight forward sound pressure based ISO 3741 and ISO 3744 method for total sound power
The reference power method
Marius Morariu – Morariu Consultancy Limited
Peter J. G. van der Linden – Qsources bvba