Despite considerable time and money being spent with the supplier and acoustic consultant installing silencers and reducing fan speed, a noise abatement notice was due because of numerous complaints about combustion fan noise. We resolved the problem overnight via Barry welding in 22dB of attenuation during a normal shutdown...
Combustion fan noise from a new waste heating system at a Palgrave Brown MDF site had caused numerous complaints from neighbours with a noise abatement notice in the offing. The fan system supplier and their consultants had tried conventional measures (additional silencing and reduced fan speed) over an extended period to no avail.
On the point of admitting defeat, they were referred to us by the local Environmental Health Officer. Our solution was to control the tonal fan noise at source using Quiet Fan technology aerodynamic fan noise control. This was fitted during a few hours of scheduled downtime. The next morning, it was hard to tell that the unit was running as the tonal noise from the ID fan had been reduced by 22dB and the overall level by 9dB(A).
A quick, low-cost and permanent attenuation for the lifetime of the fan without maintenance and without affecting efficiency.
The results were so impressive that the director, Alan Fillingham, recommended that our approach should be used throughout the group.
Compared with traditional attenuators or mufflers, this approach to induced draught (ID) fan noise reduction is not only typically 70% - 90% lower capital cost with significantly reduced running costs, but it is also much more effective at cutting the low-frequency tonal content that is a common cause of environmental noise complaints. It can also be used on fans that run at high temperatures.