Nearby residents complained about the noise when a company started operating a centrifugal fan to extract smoke from a fire test rig. Another company in an adjacent office also complained. The fan is attached to a smoke scrubbing plant and a tall chimney / stack as shown in the above photo. All this equipment is outside the building. Although the fan and scrubber plant operated during daytime hours only, the company wanted to be able to run it at night in future.
First, the company contacted the equipment supplier who returned to site and fitted cladding around the fan. Noise complaints continued. The company then tried installing a tall wooden barrier around the fan and chimney / stack. This had little or no effect on the sound as residents continued complaining (if you want to see the wooden barrier, click noise reduction at Midlands company.
The company wondered if the chimney / stack was acting like an organ pipe and amplifying the fan hum. At this point they contacted us and asked for our help.
Our noise survey showed that at the nearest houses, the fan noise from the smoke extractor, scrubber and chimney / stack exceeded the daytime background noise by 9 dBA. There was also a loud hum sound that was very noticeable and the main cause of the noise complaints. Allowing for the hum, a BS4142 noise assessment indicated that the corrected noise at the houses exceeded the daytime background by 15 dBA. So a solution needed to reduce noise by at least 15 dBA for daytime operation and substantially more to be able to run at night.
We selected a high performance, low resistance silencer to be installed in a carefully selected location within the chimney / stack. We also used advanced technology to reduce the hum sound. The noise reduction modifications were designed to have no noticeable effect on fan extraction performance. Our solution was highly successful, making the fan inaudible at the houses and also at the adjacent company's office. In fact, the scrubber system could only be heard when standing close to the fan and chimney / stack. There have been no more noise nuisance complaints since our solution was installed.
To find out how we can help you with a fan noise problem, click fan noise advice or ring the number below.
Or to see other examples of our fan noise solutions, click exhaust fan noise reduction.