Acoustic Survey Report

Client: Mr. Lakshman Chandrasekera - Chief Executive London Mutual Credit Union4 Heaton Road Peckham London SE15 3TH Project Brief: Following e-mail contact from Mr.Chandrasekera a quote was produced and subsequently an order place for an acoustic enclosure to limit the environmental noise pollution emitted from 2 Mitsubishi air conditioning condensers at the rear of the property. A site visit was made on the 1st may 2013 to acoustically and mechanically assess the noise problem and to collect sufficient data to ensure a suitable control measure. The existing enclosure offered no acoustic control, only mechanical or theft protection (see image 1). Acoustic Measurement: The following equipment was used to take readings at 1m from source: Meter: Pulsar Instruments Assessor Model 82A Serial No. 28486 BS EN 61672-1:2003 Class 2 Calibration Date 24/05/2013 Microphone: Pulsar Instruments Model MK216 Serial No. 112224 Calibration Date 24/05/2013 Site Calibrator: Pulsar Instruments Model 106 Serial No. 53984 IEC 60942:2003 Class 2 Calibration Date 24/05/2013 Recordings taken at 1m above source show the Leq being 83.5 dB The ambient noise level in the surrounding area was 72.8 dB Noise over background level 83.5-72.8 = 10.7 dB Therefore the noise emitted from the condensers is twice as loud as the surrounding area. Control of Noise: To reduce the noise output from the condensers an enclosure covering all open sides was constructed using steel as the acoustic barrier and mineral wool and the dissipation medium. The enclosure must have sufficient air flow to feed the cooling needs of the condensers but must have a baffled path to control acoustic leakage. The enclosure was fitted around the top front and sides of the condensers fixing to a cavity brick wall to the rear and sitting atop cast concrete slab floor. (See image 2) Results from Post Fitting Survey: After fitting of the enclosure was completed the noise readings were taken both inside and outside the enclosure: Noise level inside the enclosure (0.3m below source) 73dB Noise level outside the enclosure 67.5 dB Noise level at far end of property 67.1 dB (NB this is also 30m further from the roadside) As a result of the enclosure being fitted there will be no noticeable difference to Neighbouring residents when the condensers are running.

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