This case study discusses how noise testing using dosimeters helped our client determine and assess the level of noise-exposed by their workers. The case study shares the methodology used to measure noise exposure level and value delivered to the client.
Our client, a local council, wanted to determine the level of noise-exposed by their operators who work in litter collection. According to the Workplace Health & Safety (WHS) Regulations 2017, employers are required to manage health & safety risks related to noise-induced hearing loss and business should ensure workers are not exposed to noise above the exposure standard of noise.
The current Noise Exposure Standard as per WHS Regulations 2017 is an employee must not be exposed to noise of;
- LAeq 8hrs 85dB (A) – a sound pressure level equivalent to 85dB for 8hrs in the (A) frequency range; audible to the human ear with lower inaudible frequencies filtered out.
- A peak pressure level of 140dB (C) – a peak noise level measured in the (C) frequency range; which while including frequencies audible to the human ear also includes lower frequency noise which is not.
There were three litter collection operators whose noise exposure has to be determined and measured. The operator drives a waste collection truck, collect litter
The council has legal compliance to meet the requirements of WHS regulations 2017. In this case, the council wanted to accurately measure the level of noise the litter collection operators are exposed while working in the council.
Client faced a challenge to accurately measure the noise level as the litter collection operators travel throughout the locality to various areas and collect waste using a waste collection truck. It was difficult to conduct static noise assessment using a handheld sound level meter.
On an average, the litter collection operators work 12hours a day, and the client wanted to conduct the noise assessment with minimum disruption to work and also wanted to determine the specific noise exposure to each operator.
Based on the client’s requirements, challenges and constraints, Anitech Noise Solutions offered to conduct noise assessment using dosimeter. A dosimeter is a special purpose sound level meter that is small enough that your worker can wear the shift. Dosimeter will measure the noise level exposure wherever your worker goes and does throughout the workday. Three calibrated dosimeters were used to measure the noise level exposure of litter collection operators.
Based on the requirements provided, a work schedule was planned and sent to the client that discussed the potential dates of assessment, details of the trained noise assessor, equipment used for assessment, resource requirements and other site details. On obtaining approval from the client, the noise assessor went to Cairns to conduct the noise assessment.
The following steps were carried to conduct the noise assessment
- Before deploying, the dosimeter’s calibration was checked for currency, and an on-site calibration was conducted to ensure the dosimeter is accurate.
Note: Casella dBadge, the world’s first all-digital badge style Noise Dosimeter, was used. It is cable free and small enough to not interfere with day to day work
- The dosimeter was clipped to the worker at the start of the shift. A quick brief about the noise assessment and its advantages were provided to the employees before deploying the dosimeter. The dosimeter was clipped on the employee’s shirt with the mic kept closer to the employee’s ear. The dosimeter was then locked to by the assessor to avoid any risk of tampering.
- At the end of the work-shift, the noise assessor collected the dosimeter from the employees and stopped recording. During this time, a brief note of all the activities performed by the staff through the day was documented.
- Data from the dosimeter was downloaded unto a personal computer with the help of the software and details about the noise exposure throughout the day is determined.
The following steps were carried in calculating the noise exposure
- Data from the dosimeter showed the noise level exposure (LAeq, T) for over 11.5 hours (work hours). To obtain the LAeq8h measurement, the LAeq T reading was normalised using the formula: LAeq8h = LAeqT + 10Log(T/8) as Clause 9.3 of the AS/NZS 1269.1:2005 – Occupational Noise Management standard.
- Since the employees for work an extended shift for 11.5 hours, the normalised result was adjusted by addition 1 dB for every one additional work hours as per clause e 9.4 of the AS/NZS 1269.1:2005 – Occupational Noise Management standard.
- Cpeak reading was noted from the data obtained from the dosimeter.
The results of the dosimeter testing carried out on the three litter collection operators did not exceed the noise exposure outlined in the WHS regulations. A detailed reported was prepared the noise assessor that included the following details
- Site location
- Equipment used along with calibration certificates
- Noise Assessor and credentials
- Measurement criteria
- Graphical representation of the noise exposure
- Noise Level exposure (LAeq T, LAeq8h & LCpeak)
- Conclusion & recommendations
The report was peer-reviewed and submitted to the client. A debrief session was conducted with the client to explain the findings in the report and also answer any questions.
The local Council was able to determine and measure the noise level exposure of their litter collection operators. The noise assessment enabled the council to meet their legal compliance and also identify opportunities to reduce or eliminate high levels of noise. By Using dosimeter to measure noise level, Anitech Noise Solutions were able to meet the council’s requirement considering its constraints. Dosimeter provided noise level measurement that was specific to the worker.
Since the noise assessment was conducted as per the requirement of AS/NZS 1269.1:2005 – Occupational Noise Management standard and by a trained noise assessor, the report was in compliance with the legal requirements and were used as documented evidence as part of health & safety legal records.