Case Studies

Pontefract | Noise Assessment

—  Pontefract

Canterbury bat

Noise Issue

Northern Power Grid were informed that a residential planning application was set to bring housing to within 22m of the two electrical transformers on Pontefract Substation. The concern was that electrical transformer noise has the potential to disturb residents with greater disturbance at night when things are quieter. dB Attenuation Limited were commissioned to undertake a noise survey and noise modelling exercise to determine the extent of transformer noise affecting the closest houses. The acoustic consultancy was undertaken by dB Attenutation's sister company dB Consultation Limited.   

Noise Assessment

In October 2018 dBC attended site to undertake a noise survey. During the visit, the transformer sound powers were determined and environmental noise measurements were taken around the substation and surrounding land earmarked for residential development.
Electrical transformer noise is characterised by a hum at 100Hz. It is this hum that causes residential complaint. At proposed plot 63, 22m from the transformers, the noise model predicted a level of 60dB at 100Hz. In our experience, this level is almost certain to be audible within a house and result in complaint. 
This information was passed to the developer who agreed to assist Northern Powergrid in introducing an acoustic solution to reduce transformer noise to a level where future complaints were unlikely.   

Acoustic Solution

dBC recommended that 100Hz noise should be reduced by a minimum of 25dB.
The acoustic solution to achieve this reduction was full enclosure of the two transformers. dBA undertook a full design and build of two hi-specification enclosures and in July 2020 completed the installation. 
A post installation noise survey in October 2020 determined the 100Hz insertion loss of between 25 and 31dB around both enclosures. 
The acoustic solution ensures the prospect of complaint will be reduced to a minimum within the residential development.
For acoustic consultancy that leads to effective an acoustic solution contact us