A pair of new cooling towers had ignited complaints from residents across the road from the site. A typical noise consultant was drafted-in who recommended the default silencers and a noise barrier without carrying out any diagnosis. Not good practice, let alone best practice.
However, the predicted effect of fitting the typical conventional acoustic package of silencers and a barrier along the edge of the site was a reduction in noise to around only 56dB(A) at the neighbours which was still too high for the area. This despite a total cost of well over £30k. In addition, as the acoustic barrier would have caused serious transport access problems, the company looked for alternatives.
Our solution was based on very accurate diagnosis and ranking of the noise sources to develop an engineering source control package. The final noise reduction measures for both cooling towers comprised intake and drive motor modifications, exhaust and pump silencers plus local acoustic screening. This achieved a noise level of <50dB(A) at a cost of only £5k and without affecting normal site operation or cooling tower efficiency. Around 16% of the cost and more than 4 times the attenuation of the conventional noise reduction measures.