The sound pressure measurement is carried out according to the following standards:
ISO 3744, ISO 3745, ISO 7779, CNS 8753, JIS 8346

The test setup is as follows: The fan in free-flow mode is suspended in vibration-free position at a distance of 1m from the microphone, and the entire setup is located in an anechoic chamber.
We understand these values are only moderately suitable for practical use in PCs, but unfortunately, we cannot create our own standard.

Installation applications such as on a heat sink or in an enclosure can generate additional noise that cannot be represented in such a measurement.