The proposed £100k conventional attenuators for 10 axial mine water evaporation fans in Australia would have had zero effect on the noise. A few emails and <£20k of elegant aerodynamic modifications provided an 18dB noise reduction and improved fan efficiency, making the project profitable!
The Australian mining company used a series of 10 large axial fans to evaporate water pumped from underground into a reservoir. However, these fans were the cause of complaints from residents over a very wide area.
The quote for £100k of mufflers would have provided zero attenuation as they would be fitted only to outlets, whereas half of the noise was radiated from the intakes. In addition, they would have provided virtually no attenuation at the dominant 198Hz tone.
The solution
Our remote noise control service diagnosis allowed us to evaluate the problem using information and recordings provided by the client by email, saving a visit from the UK to Australia...
We designed and emailed retrofit aerodynamic fan noise control modifications for local manufacture. These reduced the tonal content by 18dB and the overall dB(A) by 70% at a cost of <£2k/fan.
As fan efficiency was also significantly improved, this was a profitable, self-financing project for the client.
