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October 2011

The purpose of this information sheet is to provide guidance on the hazards associated with occupational noise and control measures to be implemented in order to minimise their impact on health.

Noise is defined as all sound in the workplace, either wanted or unwanted and is one of the most common Occupational Health and Safety (OHS) hazards and is found in many different environments. Prolonged exposure to excessive noise can result in irreversible damage to a person's hearing and a reduction in their quality of life.



Decibels, a logarithmic unit of measurement for the loudness of sound


'A' weighted Decibels, which approximates how the human ear responds to noise at moderate levels


'C' weighted Decibels, which approximates how the human ear responds to noise at very high levels


Is a standard that hearing protection is measured against. An SLC80 rating indicates that the hearing protection will provide at least the listed attenuation to at least 80% of users

Nuisance noise

Nuisance noise is noise that does not cause hearing loss, but may have a psychological effect and impact on performance. The causes of nuisance noise are wide ranging and can be quite difficult to control. Due to its effect on employees, it should be minimised where possible and should be managed at a local level.

Area or equipment

Typical noise
levels dB(A)



Typical office


Typical lab




Vacuum cleaner


Typical factory


Noisy lawn mower


Belt sander


Hand drill


High pressure spray painting


Angle grinder





Under the Occupational Health and Safety Regulations 2007 Monash University must ensure that its employees are not exposed to noise greater than the noise exposure standard, which is an average of 85 dB(A) for 8 hours, or to any instantaneous noise in excess of 140 dB(C). Note that noise exposure approximately doubles with every 3 dB. For example, the noise exposure standard is exceeded after 4 hours at 88 dB(A) or 15 minutes at 100 dB(A).


A noise assessment must be conducted when there is uncertainty about whether or not employees are being exposed to excessive occupational noise. A noise assessment involves measuring noise levels generated by machinery and processes, as well as the levels received by the worker's ears. Additionally, noise assessments can provide valuable information for controlling noise. A noise assessment can be arranged by contacting Occupational Health and Safety on x51016.

Primary controls

Legislation requires that noise exposure must be controlled in a systematic way, and must start with an effort to remove the source of noise from the work environment or to reduce the amount of noise that is generated.

Controlling the noise at the source through a process of elimination or engineering measures can be done in a variety of ways and is often easier in the long term than a personal protective equipment program. Rethinking how a task can be done can greatly reduce the amount of noise. For example, bending a strip of metal using a hammer generates a great deal of noise, changing techniques to bending it with a vice and pair of pliers is a much quieter alternative.

Some effective and practical methods for reducing the amount of noise employees are exposed to include installing springs and rubber strips to reducing the amount of vibration and resonance of the equipment, enclosing noisy equipment with noise absorbing/reflecting material, moving the source of noise away from where people work and purchasing quieter equipment. Additionally, well-serviced equipment is often quieter, so ensuring that equipment is in good working order will reduce noise exposure.

Secondary controls

Administration controls such as training, signage, limiting duration of exposure via work rotations and having 'no-go' areas, while not as good as eliminating noise at the source, are also effective ways of reducing noise exposure. If both primary & secondary measures do not reduce the noise exposure to an acceptable level, personal protective equipment will be required.

Personal protective equipment (PPE)

Personal protective equipment can be used if all other controls do not reduce the noise levels to an acceptable level. The appropriate level of hearing protection must be used corresponding with the level of noise exposure.

Earplugs are often used as an alternative to ear muffs. These can often be more convenient, but generally do not offer the same level of protection. The most common reason for the reduction in protection is due to improper fitting of the plug. Those using earplugs must receive training on how to fit them correctly and must follow these instructions. Videos can be found online for good fitting techniques.

It should be stressed that hearing protection is a lower order control and should not be sort as a quick and easy solution. Furthermore, over time hearing protection degrades as the headband stretches, seals become hard and foam wears out, therefore a maintenance program must be developed to ensure that hearing protection is working effectively.

Buy quiet policy

With a proactive purchasing policy, a number of noise hazards may be eliminated before they enter the workplace. The purpose of a 'Buy Quiet' policy is to control noise at the earliest stages of planning and design by encouraging the minimisation of noise generation by purchasing inherently quieter equipment. Australian suppliers and manufacturers of noisy equipment are required by law to provide information on the amount of noise generated by their products, so you can make an informed decision on which piece of equipment to purchase.

Quieter equipment can be more expensive in terms of its upfront cost, but this is usually offset by a higher quality product lasting longer and performing better. Additionally no noise reducing retrofitting will be required and it will decrease the reliance on PPE programs. All university departments are encouraged to adopt a "Buy Quite" policy where staff and students have the potential to be exposed to excessive levels of noise.


Any employee who is required to wear hearing protection must also have an audiometric test every two years. The Occupational Health and Safety branch co-ordinate audiometric testing as part of its health surveillance program. Additionally, audiometric testing may be conducted pre-employment for at risk groups to establish base line hearing levels.

For further information, contact Occupational Health & Safety on: