Low Frequency Measurement Guidance

The Nor1026 NorReview Software is for post processing and reporting of your Nor139, Nor140, Nor145 and Nor150 measurements.

This articles covers the procedure for the assessment of low frequency noise complaints by Salford University.

Requirements

NorReview software must be installed..

Nor140 or Nor145 instrument with with 1/3 octave logging enabled and audio recording and FFT mode. See our tutorials on the right for meter setting configuration.

Procedure for the assessment of low frequency noise complaints

Low Frequency Noise (LFN) has become a recognized issue globally, though it affects a relatively small number of people. Those impacted can suffer severe distress, including sleep disruption, depression, and even suicidal thoughts. While sometimes a noise source is identified and resolved, in 50–80% of cases no obvious environmental source can be found, making the disturbance mysterious.

Local Authorities in the UK frequently receive LFN complaints but struggle to address them due to several challenges:

Standard noise measurements (dB(A)) filter out low frequencies and are therefore unsuitable.
Investigators often cannot hear the LFN themselves, as it may be just above the hearing threshold and vary greatly among individuals.
Perception of LFN can increase over time (sensitisation), meaning short investigations may miss the true impact.
Technically, measuring low-frequency sound is difficult.

Several European countries have introduced criteria for acceptable LFN levels since 1997. The UK’s Department for Environment, Food & Rural Affairs (Defra) commissioned this guidance to develop an assessment method suitable for UK Environmental Health practitioners.