BKL was engaged by the Township of Langley, BC, to assess whether noise from a large warehouse distribution facility exceeded the municipal noise bylaw daytime and/or nighttime limits. The nearest residents were about 300 metres away and were complaining about trucking activity noise emanating from the facility.
The wording in the municipality’s noise bylaw defined the “point of reception” at the edge of the noise maker’s property. Therefore, two unattended 48 hour measurements were made at the corners of the property nearest the residences in order to determine bylaw compliance. Meteorological parameters such as wind speed, wind direction and solar radiation were also recorded with our portable weather station so that sound levels could be estimated at the residential facades if need be. Collecting these weather parameters plays a large role in predicting sound propagation over large distances because effects such as temperature inversions/lapses or upwind/downwind conditions can greatly influence receiver levels.
To further complicate matters, a high traffic heavy rail line was in operation between the warehouse and residences, which had the potential to make it difficult to know if a measured noise level was due to trucking or train noise. The rail line does not fall under the jurisdiction of the noise bylaw. In order to identify and subsequently exclude the rail events from the measurement results, audio was recorded simultaneously on our Class 1 sound level meter when the sound level exceeded a predefined threshold.
Since our sound analysis software synchronizes the measured sound levels with the audio file, we were able to efficiently review the audio at locations where the sound level exceeded the noise bylaw limits.
It was found that wildlife calls were the only sounds besides train pass-bys that exceeded the bylaw limits at the microphone locations. This would have been very difficult to prove without audio recording capability.
BKL has performed many other bylaw measurements in other municipalities. We have also consulted various municipalities with regards to creating or revising noise bylaws.