Approaching £50000 had been spent on silencing two large, roof mounted fans in an attempt to satisfy local complainants and the Environment Agency authorities – unfortunately without any success due to a lack of diagnosis of the cause of the noise problem. When the company approached us to provide them with a solution, we asked them to email us a couple of video clips of the fans.
Our initial diagnostic analysis of the video sound-tracks showed that the noise issue was caused by the interaction between the blade pass tones of the 2 similar fans that caused "beating" - modulation of the tonal level that adds to the subjective nuisance. This allowed us to design our unique Quiet Fan technology aerodynamic inserts to reduce the noise by over 20dB at source without enclosures, silencers or lagging – permanently and without maintenance. This was achieved with minimal down-time and at a tiny fraction of the cost of conventional alternatives. Read more on fan noise control without attenuators.