Severe noise problems were encountered from the fans in a new regenerative thermal oxidiser plant on an industrial site. The suppliers suggested an earth berm noise barrier, large fan silencers and acoustic enclosures that would not only have cost a 6 figure sum, but would have been a complete waste of money as they would not have worked as the problem noise emanated from the top of the stack.
We used precise diagnosis to isolate the key subjective sound features in addition to the overall broadband noise that dominated the dB(A). The optimum noise control modifications involved:-
- we removed the tones using our aerodynamic fan noise control technology
- one fan was slowed to remove the “beat” with the other unit
- the dampers were moved to improve flow
- small conventional attenuators were added to reduce broadband noise (as the low frequency elements had been removed, only small silencers were required).
These modifications eliminated all the noise character and reduced the overall noise by 15dB(A) at a few % of the costs associated with the proposed traditional (and largely ineffective) noise control package.
