Noise Control Memo Simon Renton
Environment Safety \& Health Directorate
Memo
To: Diane Robinson From: Simon Renton Date: 28 May 04
PA 03/1421 - 16 Michael St Peel - Noise Control
Further to my memo of 28 April 04 I visited the site and met the owner on Tuesday 25 May 04 .
The background noise levels were $35 \mathrm{~dB}(\mathrm{~A})$ and as stated in my previous memo to prevent noise nuisance to local residents I recommended a noise limit not exceeding background levels. The installation engineer Dick Raine provided the manufacturers data which indicated noise levels would be $57 \mathrm{~dB}(\mathrm{~A})$ from the fan at a distance of 3 metres. He believed that the attenuators either side of the fan would reduce noise levels by 5 $\mathrm{dB}(\mathrm{A})$.
I can only conclude that this extractor system is very likely to cause a noise nuisance to local residents, producing noise levels of approximately $17 \mathrm{~dB}(\mathrm{~A})$ above background ( 57 dB source -5 dB attenuation -35 dB background).
Furthermore the extractor system ducting is so close to the residential accommodation above ( 18 Michael Street) that it is likely to provide transmission of noise from inside the kitchen itself. In other words the residents above may be able to hear noise from the voices of persons cooking in the kitchen, banging pots and pans, radio noise, etc. transmitted via the three large holes cut in the roof and connected to ducting. This ducting can act like an amplifier particularly at certain frequencies. Also as the properties are structurally attached there is the risk of structurally transmitted noise.
In my opinion this system has been insensitively located in respect of potential noise nuisance to local residents. It would be preferable to locate the kitchen and ducting at the rear of the premises further away from residential accommodation, allowing more opportunity for sound attenuation, reduced risk of structural transmission of noise and better dispersion of fumes from the exhaust.
Possible means of reducing noise from this extract system include:
- Installation of a quieter fan;
- Acoustic lagging of the ductwork or enclosure by other sound attenuating structure;
- Relocation of the cooking area, and subsequently the extract system, to the rear or first floor area of premises (further away from residential premises).
Furthermore I would stress that if the premises are restricted to stop their extract system at 10.30 pm , operation of the premises also has to be restricted ( 11 pm proposal) because if cooking continued without extraction additional problems would include: i. The cookers are likely to require to be extracted by Health \& Safety Regulations. ii. There would be inadequate ventilation no doubt resulting in opening or windows and doors, exacerbating any problem of noise from the kitchen to local residents.
Again I would advise that in granting planning permission the council would be providing the applicant with the defence of 'best practicable means' in respect of any noise nuisance proceedings by the Department under the Public Health Act 1990, which in my opinion is very likely in respect of the current proposal.
I would recommend that the applicant seeks specialist advice from a noise consultant and a revised plan to ensure that noise from the extract system does not cause a nuisance to neighbours.
