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Safe Environments Pty Ltd was commissioned by a company specialising in water treatment to undertake an occupational noise survey during the commissioning of the recently constructed Reverse Osmosis (RO) water treatment plant located in regional NSW. The NSW site comprises a reverse osmosis plant which treats water from a mining operation, removing contaminants through the use of membrane technology. The noise produced during the process primarily appeared to be through pumps forcing water through pipes, pressure differentials from valves, and compressors blowing air to oxidise water during the treatment process.

Noise Level Design Requirements

The requirements for the water treatment plant included a design note within the contract that the maximum Sound Pressure Level (SPL), within one meter of any item, must be less than 85 dB(A), with a design target of 75 dB(A). A procedure was also required to outline what method would be undertaken and that a competent person was engaged. Safe Environments was able to demonstrate its level of experience in providing high level occupational hygienists and calibrated sound level meters that could record frequencies in the 1/3 octave bands.

With a short time period before testing was required, Safe Environments attended the NSW mine site to ensure that the noise survey could be undertaken in short period of time. The sound level measurements were conducted to AS/NZS 1269.1:2005 Occupational noise management – Measurement and assessment of noise emission and exposure and were then able to be provided to the principle the following day of the sound level measurements being undertaken. In this instance the inspection could be undertaken swiftly due to the minor noise fluctuations on site during the plant testing process.

Inspection Testing Procedure

Sound Level Measurements were taken within 1 meter of equipment, at a height of approximately 1.5 m of the noise generating equipment for the reverse osmosis plant that were observed to be noise generating. The noise generating equipment for the reverse osmosis plant tended to include pumps and valves where force was exerted or there was significant differential pressure. The sound pressure levels were recorded over a representative period, generally of 30 seconds duration where there was minimal fluctuations (i.e. less than 0.5 dB(A) over 30 second time intervals, being confirmed at times throughout the inspection process).

Assessment of Noise

The noise testing was able to undertaken in a number of operational modes which would then be able to be used in order to assess the likely overall daily noise exposure that a worker may be exposed to. With a number of operational modes, a number of sequences could be used to optimise the noise exposure and the output of the water treatment plant. In addition the noise levels that were measured could be used in noise prediction software to assess how noise minimisation strategies could affect the overall noise exposures.

Workplace noise is one of the most costly and prevalent injuries which can be prevented by safe design principles. For more information on noise survey during design, please contact one of the Occupational Noise Consultants in Sydney or Melbourne.

Author: Carl Strautins

Carl Strautins


Carl Strautins is a managing director of Safe Environments Pty Ltd a multi-specialist consultancy operating in the building, construction and property management industries. He provides the necessary guidance and risk minimisation strategies required by architects, construction companies and facility managers to ensure they mitigated their risk to property risk. He is engaged on a regular basis to provide expert opinion for disputes and legal proceedings. Click here to know more about him.