Noise Assessments in the Workplace
To determine if the workplace noise levels exceed the exposure limits, a noise consultant will first undertake a preliminary noise assessment. This preliminary noise assessment is used to document the sources of noise in the workplace and to determine the nominal noise levels. If noise levels in the workplace are greater than 80 dB(A) then a detailed noise assessment is required to be completed by a Qualified Occupational Hygienist using NATA calibrated sound equipment.
Workplace Noise Regulations in Sydney and NSW
Workplace noise regulations are governed by NSW Work Health and Safety Regulation 2016.
A Person Conducting a Business or Undertaking (PCBU) at any workplace must manage the risks to health and safety relating to hearing loss that is associated with noise. This includes ensuring that workers are not exposed to levels of noise that are greater than the exposure standard.
AS/NZS 1269.1:2005 Occupational Noise Management – Measurements and assessment of noise immission and exposure states that the Workplace Noise average levels for the work day (8hours) should be less than LAeq, 8hr of 85dB(A) and the peak noise level should be less than LC, peak of 140 dB(C).
Noise is the variation of air pressure comprising compressions and rarefactions of longitudinal waves. It is the magnitude of the compressions and rarefactions that determine the level of the noise. As the level of noise increases, the risk of Noise Induced Healing Loss (NIHL) increases.
A person can generally recognise a 1 – 3 dB change in the level of noise. However, the perceptions of noise levels are different to the actual energy that the ear is subjected. The perception of noise levels double every 10 dB, however the increase in energy experienced by the ear is doubled every 3dB. When it comes to the potential for noise induced hearing loss, it is the noise energy level that is critical. The noise energy levels considered to be excessive when noise levels exceed LAeq, 8hr of 85 dB(A) and LC, peak of 140 dB(C).
As a general rule, if you have to raise your voice when talking to someone 1 metre away then it is determined that there is excessive noise levels. (presuming both persons have normal hearing).
Noise levels can be steady state or impact. Steady refers to the continuous noise levels not varying by more than 6 dB(A). Impact or impulse noise occur from a sudden peak in noise followed by an exponential decay which may cause acoustic shock for example a hammer striking steel.
How ADE Tests Workplace Noise
The detailed workplace noise assessment assesses the likely noise exposure over an eight-hour equivalent working day and can be completed ideally by personal noise monitoring using NATA calibrated noise dosimeters. These dosimeters are worn by the workers for the duration of their work shift. The daily workplace noise exposure for that worker can then be assessed and compared to the Occupational Exposure Limit for noise.
Another method of measuring the noise levels in the workplace is to complete noise contour mapping using a NATA calibrated sound level meter. The noise contour survey measures the level of noise in the areas of the workplace that may be impacted by noise that is produced by machinery. Sound levels are taken throughout the workplace and the overall workplace noise exposure is determined.
If the noise survey determines that the workers are exposed to excessive levels of noise in the workplace then appropriate control measures are suggested to assist in the reduction of the total workplace noise exposure to less than LAeq, 8hr of 85 dB(A) and LC, peak of 140 dB(C).
Some of these noise control measures may include:
Isolating the worker from the noise;
Implementing sound barriers or modifying the equipment/machinery so that the level of noise is not so high;
Training on what noise is and how to reduce or manage it;
The different types of hearing protection, how to wear the hearing protection and the care and maintenance of it
Health monitoring which includes conducting audiometric testing (hearing tests) at a maximum of two yearly intervals.
If you require further advice on workplace noise levels, assessments or noise testing to help you provide safe noise levels in the workplace, please contact the ADE teams in Sydney, Melbourne or Newcastle to speak with one of our Occupational Hygienists.