Blog - Slip Testing
Noise Survey South Western Sydney Campbelltown MintoPosted 9th July 2014, Carl Strautins
The Occupational Hygienists at Safe Environments undertook a noise survey at a production facility in the Campbelltown industrial area. Safe Environments undertake noise surveys regularly to south western Sydney suburbs of Liverpool, Campbelltown, Minto, Ingleburn, Narellan and Prestons.
The facility in this instance manufactures bottles made from Poly-Vinyl Chloride (PVC), Poly Ethylene Terephthalate (PET) and High Density Poly Ethylene (HDPE). The noise survey was requested as a new production facility has been constructed. The same machines were used, however due to the change in the lay-out the previous noise survey was no longer valid.
Measure noise with Sound Level Meter (SLM) or Dosimeters?
The sound within the facility was not of a fluctuating type, and was continuous within a 6 dB range. This allowed the noise survey to be conducted using just a hand held Sound Level Meter (SLM) to take noise measurements at points throughout the south western Sydney factory. The exposure to noise may also be undertaken through the use of noise measuring devices that are attached to the worker over the day. The devices are known as Dosimeters.
Sound Level Meters may not measure representative sound exposed to workers
While it was possible to take noise measurements using only a SLM, our experience is that the overall daily noise exposure may be significantly different due to the specific activities that the workers may undertake.
This was true in this particular instance: the noise within the Campbelltown factory was generally between 80 to 86 dBA and whilst this was similar within the south western Sydney production facility, the noise exposure different. The difference was not due to the average exposure (LAeq), but was different due to the peak sound measurements.
During the noise survey using the SLM of the Minto facility, there were no peak measurements greater than 110 dBC, however there were many readings greater than 140 dBC. These LC peak measurements are impact noises created as a result of the workers hitting and striking using tools. These noises are particularly hazardous as they may perforate an ear drum or cause instantaneous damage to the ear.
Advantages of using both SLM and dosimeters
This noise survey shows the advantages of using both Sound Level Meters (SLMs) and Dosimeters to assess the risk and determine the required controls. The sound levels of around 85 – 90 dBA requires Class 1 Personal Hearing Protection (PHP), however Class 1 hearing protection is generally not available, consequently Class 2 PHP should then be used.
The LC Peaks that were measured to be greater than 140 dBC changes the requirement to then be Class 5 hearing protection as per Appendix B2 of AS/NZS 1269.3 Occupational noise management Part 3: Hearing protector program.
Controlling impact sounds- Lc Peaks
The challenge that the Campbelltown facility faces is that the Class 5 Personal Hearing Protection will overprotect the worker from the majority of noise and make workers feel isolated and potentially not recognise warning tones from forklifts or cranes and the like.
The focus for the Campbelltown facility in South western Sydney is to reduces the impact sounds so then the hearing protection can be reduced as not to overprotect and isolate the worker from their environment. One way to reduce impact noise is when using hammers to use hard plastic / nylon rather than metal. The metal on metal contact provides the impact noise quite capable of exceeding the 140 dBC.
If you require a noise assessment and are based in South Western Sydney, Liverpool, Prestons, Minto, Ingleburn, Moorebank, Minto or Campbelltown, please contact Safe Environments to assist in managing your workplace risk.