Acoustical Consultants Portfolio
Featured Acoustic Projects
A selection of projects that show how Noise and Sound Services works — from first measurements through to practical recommendations.
Industrial Acoustics
Noise Assessment for a Gas Treatment Plant
The Project
Noise and Sound Services was requested to carry out noise measurements and produce a noise assessment for a gas treatment plant.
The Challenge
The assessment was used to establish baseline noise data to ensure that the equipment meets the noise regulations when situated in a location near residential premises. The main noise emission from the gas treatment plant was found to be from an exhaust fan system.
What We Did
Site specific noise criteria were 45 dBA for day time and 35 dBA for night time. As the gas treatment plant is required to operate continuously for 24 hours per day, the noise goal (LAeq, 15 minutes) was 35 dBA.
The measured noise level (LAeq, 15 minutes) at 2 metres from the exhaust fan system was between 72 dBA and 80 dBA depending upon the measurement direction. This gives a sound power level (LWA) of 91 dBA with a directivity correction (Dc) of 4 dB.
The Outcome
The assessment results showed that a distance of approximately 175 metres is required to meet the site specific noise goal. This is in the worst-case direction (i.e. facing the fan exhaust system air inlet) and assumes soft ground conditions (grass or earth between the source and the receiver) and normal weather conditions.
35 dBA
Night time noise goal met
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We specialize in providing comprehensive, council-compliant acoustical reports for regional NSW & Sydney.
Industrial Acoustics
Fan Noise Control
The Project
An exhaust fan was installed in an area with a quiet background noise level. The noise level (LAeq, 15 minute) at the nearest residential neighbouring property, at a position of approximately 6 metres from the noise source, was 54 dBA with the fan at full speed (100% - 1700 litres per second). This exceeded the 42 dBA noise criterion by 12 dB.
The Challenge
However, this speed and air flow rate was not necessary for the required function of the fan. The solution was to fit a variable speed controller. The fan speed could then be reduced by approximately 50% to 850 litres per second which reduced the noise by the required 12 dB.
What We Did
The noise level (LAeq, 15 minute) at the nearest residential neighbouring property, at a position of approximately 6 metres from the noise source was then measured at 44 dBA with the fan at half speed. This indicated that measured level was still 2 dB over the noise criterion. This sound level includes some ambient noise even though the measurements were carefully taken to exclude extraneous noise from aircraft and bird song. The continuous ambient was noted to be generated from distant road highway traffic noise which was approximately 300 metres to the west. And also, from a secondary collector road which was approximately 240 metres to the north of the subject site. These factors prevented a direct measurement of the source noise alone.
The Outcome
Hence, the site-specific ambient noise (LAeq, 15 minute) was measured with the source noise off. This was 40 dBA and allows the source noise alone to be calculated from the acknowledged acoustical formula Lp = 10 log10 (10^(Lp1/10) – 10^(Lp2/10)). Lp is the source noise level alone, Lp1 is the source with the ambient noise level and Lp2 is the ambient noise alone. This proved that the noise criterion of 42 dBA was met. From 42 = 10 log10 (10^(44/10) – 10^(40/10)).
42 dBA
Criterion met
Need a similar industrial assessment?
We specialize in providing comprehensive, council-compliant acoustical reports for regional NSW & Sydney.
Have a project that needs a noise assessment?
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