Noise

Occupational Noise Requirements

NSW WorkCover statistics Bulletin 08/09 indentify industrial deafness accounting for approximately 36 % of all occupational injuries. Industrial deafness is irreversible and is preventable. The NSW OHS regulation requires that appropriate controls measures are in place if people are exposed to:

• 85 dB(A) average equivalent for 8 hours
• 140 dB(C) peak

Noise Surveys

A basic walkthrough noise survey will assist to identify if people may be at risk of noise induced hearing loss.  If noise levels exceed 80 dBa then a more detailed noise survey is required and it is recommended that the principles of AS/NZS 1269 Occupational noise management be implemented to identify, assess and control the risk of noise induced hearing loss.

A detailed noise survey is conducted by taking noise level measurements to provide a contour map of excess noise sources and effects of reflecting surfaces and reverberant fields. Further measurements are taken during specific tasks to then assess the noise exposure to the workers.

Noise Exposure

Noise measurements are undertaken to AS/NZS 1269.1 Measurement and assessment of noise immission and exposure in near proximity of the workers ear during the task using a Class 1 Sound Level Meter (SLM) to obtain the average noise exposure. By assessing all tasks normally conducted during the day, the total daily noise exposure can be calculated.  Alternative a Personal Sound Exposure Meter (PSEM) which is also known as a dosimeter will integrate and average the noise recorded during the day to provide the total noise exposure to the worker

Controlling Noise

The ranking of the activities and noise sources allows to each exposure group provides a basis to systematically control excessive noise through buying quiet equipment, eliminating processes, engineering controls (source, path or receiver), administrative controls or through hearing protector programs.

While not all noise levels can be reduced to acceptable limits, the use of hearing protectors may be required. The selection process relies on the noise levels and specific frequencies to be anticipated. Reducing noise levels below 70 dBa can also introduce issues relating to overprotection, or isolating workers from stimuli that assist with perception of the working environment.  Noise awareness training along with proper instruction on the use and maintenance of hearing protectors are required.

Health Surveillance

Audiometric testing to AS/NZS 1269.4 auditory assessment should be conducted for those at risk. Baseline levels should be conducted prior to starting work with annual assessments to determine hearing threshold shifts and potential noise induced hearing loss. Auditory assessment should also be conducted at the termination of employment to quantify any change in hearing loss. This is particularly important for employers to protect against claims for which they have not significantly contributed to.

The process briefly explained are the core components of an occupational noise management system which should be reviewed annually or when significant changes in exposure to noise may occur.