Solving a Low Frequency Noise Problem
Fever Bar, Shrewsbury
All is not straight-forward regarding potential neighbour annoyance when a nightclub wants to expand its operations into a former first floor office space. Nightclub music is played at reasonably high levels in excess of 95dB(A) and is characterized by its low frequency content. The office space had single-glazed windows, roof lights, common separating wall with a restaurant and neighbouring residential dwellings at 15m from a fire exit door. The owners of Fever Bar in Shrewsbury needed experts in building acoustics and low frequency industrial noise control to ensure noise break out and potential disturbance was reduced to a minimum.
The solution to this problem turned out to be a collaborative solution between the dB Group of companies dB Consultation Ltd. and dB Attenuation Ltd. The building acoustic expertise of dB Consultation Ltd. was used to assess the sound insulation properties of the existing building shell and find potential weakness areas. The assessment of noise break out highlighted the obvious weakness in glazing but found the building facade had incomplete walls, degraded roof boarding and ill-fitting door seals all potential noise leakage areas. The overall sound reduction index of the single-glazed facade was estimated at Rw 27dB whereas the nightclub would need a level in excess of Rw 50dB to function normally. dB Consultation Ltd. produced a raft of noise control and mitigation measures to upgrade the entire first floor sound insulation. The work was entirely planned and delivered by dB Attenuation Ltd. who have particular expertise in industrial noise control especially the electrical distribution network. The measures included, blanking off and sealing all openings, effectively producing a room within a room with new dry-lined walls and ceilings and replacing roof boarding. The final piece of the jigsaw was the design, manufacture and installation of new acoustic fire door.
The nightclub was fully fitted out and dB Consultation Ltd. returned to site to assess noise breakout. Simultaneous measurements on the dancefloor and at locations across the flat roof established that the works had considerably raised the sound insulation of the building, the sound reduction index had increased to an estimated Rw55dB with measurements showing considerable low frequency reduction. Sound attributable to nightclub music was barely audible across the low flat roof and did not raise the ambient sound levels measured at the nearest residential neighbour to the club.
Since the works, Fever & Boutique nightclub has operated throughout the summer without complaint from neighbours which is a rare event for nightclub venues when people have their windows open.
Mick Lane BSc (Hons), DipIOA, MIOA
Consultant, dB Consultation Ltd.
December 2016 to September 2017