The company running a server farm had spent £100,000 on noise control measures (acoustic barriers and silencers) for their HVAC and AHU plant to no avail – the complaints continued as the noise levels were virtually unchanged. We were invited by the Local Authority to provide both parties with a definitive statement as to what constituted “best practicable means” and to sort the problem.
Careful diagnosis allowed us to generate a best practice noise control package that would eliminate the problem at a cost of c £30k.
These measures included purpose designed silencing, geometry changes, improved acoustic screening and internal modifications to the main Air Handling Units. On the air conditioning condenser units, we by-passed the conventional solution of noise barriers and silencers as these are not only high cost control measures, but they can also reduce the efficiency of the chillers themselves. Our alternative was a set of low cost engineering noise control modifications that not only reduced the overall noise from the HVAC plant at source by 8dB(A), but also eliminated the tonal content (worth an additional 5dB(A) noise reduction with respect to environmental noise limits) – and with no effect at all on the chiller condenser performance or access.
The result was an overall noise reduction of 12dB(A) and the elimination of the tonal content of the noise from the condensers. If best practice had been used at the start, the company would have reduced the cost of the chiller plant noise control project by 70% and avoided several months of management hassle and a sacking…