Both noise measurement and service life must be explained to be understood.
Measurement is a standard procedure that takes place in a noise measurement chamber. For this purpose, the fan is suspended from rubber ropes and measured at a defined distance of one meter to the fan hub (air intake side). The corresponding standard is ISO 7779.
The values can be used for orientation purposes, however do not represent the actual noise emitted when installed in the respective application. Significant influential factors, e.g. type of installation, housing construction, housing material, dynamic pressure and unfavourable flow conditions are disregarded during measurement, yet they have a considerable influence on the noise of the fan in the respective application.