Case Study - Acoustic Attenuation
Greencore
With the installation of new extraction systems, new environmental legislation dictates that simple air discharge to atmosphere is not always acceptable. Greencore Bow of London therefore employed JJ Ventilation to ensure noise breakout from their increased capacity extraction system did not exceed the acceptable limit.
Problem
Greencore Bow of London have over the years enlarged their sandwich making factory to incorporate facilities suitable for the production of a range of healthy pasta meals. The additional production line created a need to increase the performance of their existing steam extraction system which exhausted to the side of the building. Modifying the existing extraction system resulted in increasing noise break-out at the factory boundary to 78 dB(A) and this attracted complaints from occupants of neighbouring properties.
Solution
In order to achieve reasonable noise levels at the factory boundary, a JJ Ventilation Engineer visited site, and using state-of-the-art technology, confirmed the excessive noise levels in each octave band. Due to the discharge of steam and additional cleaning agents, special consideration had to be given to attenuator design to ensure that the required reduction in velocity within the attenuator was reached and the high performance attenuation required was achieved within the limitations of space available.
Using the JJ Ventilation Cartridge System of splitter-attenuator design, the internal components of the attenuator were manufactured to provide best acoustic absorption at worst octave band frequencies.
The overall result was a reduction of 15 dB(A) which easily met the design criteria and satisfied both the client and complainants.
