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Important: From 1 January 2012, information on this website is being reviewed and must be read in conjunction with the Work Health and Safety Act 2011.

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Noise control measures

Eliminating noise in new plant and workplaces
Engineering controls for existing plant and workplaces
Administrative controls
Personal hearing protectors and areas

Eliminating noise in new plant and workplaces

Noise control measures can include the design of the installation area and the design and construction of a new workplace.

Where plant is designed for a particular workplace, designers should:

obtain agreement with the client on noise reduction and noise controls
check the impact on noise levels of locations of workstations near plant
check the transmission of noise through structures and ducts
design for acoustically sound plant rooms and control rooms where appropriate
design out noise from the external environment and design the internal environment to reduce external noise
design plant to eliminate or control noise emissions where there is a risk to a person's hearing.

Detailed information for noise control management in new and existing workplaces may be obtained from Part 2: Noise control management of AS/NZS 1269 Occupational noise management (non-Queensland Government link).

AS/NZS 2107 Acoustics: Recommended design sound levels and reverberation times for building interiors (non-Queensland Government link) gives information on acceptable design sound levels for various building interiors.

Engineering controls for existing plant and workplaces

The need for noise control should be considered when deciding production methods or processes and when the need to reduce noise exposure has been established. There are three basic engineering noise control measures:

treatment of the source
treatment of the noise transmission path
treatment at the receiver.

Examples of engineering controls can include:

reducing noisy machine operations by replacing rivets with welds
redesigning machinery power sources to give quiet speed regulation, for example through the use of stepless electric motors
avoiding metal-to metal contact by using plastic bumpers
repairing loose and rotating parts, replacing worn bearings and gears and regular maintenance
adding noise barriers, noise enclosures, vibration isolation mountings, laggings, mufflers and silencers where appropriate to reduce noise at source
absorbing acoustic shock by providing wear resistant rubber or plastic coatings
using conveyor belts rather than rollers
stiffening and fixing damping materials to panels and other surfaces to reduce vibration and noise impact of items during processing.

Other ways of reducing noise through engineering controls include:

using a sound-reducing enclosure that fully encloses the machine(s)
separating the noisy area and area to be quietened by a sound reducing partition
using sound-absorbing material on floors, ceiling and/or walls to reduce the sound level due to reverberation
using sound-absorbing baffles between workers and the noise source
using acoustical silencers in intake and exhaust systems associated with gaseous flow activity, for example, internal combustion exhaust systems or air conditioning systems.

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Administrative controls

Administrative controls should be used when it is not possible to reduce noise exposure through engineering noise control measures. These include:

organising schedules so that noisy work is done during a particular part of the shift or when as few people as possible are present
notifying people in advance when noisy work is to be carried out so they can limit their exposure to it
keeping people out of noisy areas if their job does not require them to be there
sign-posting noisy areas and providing quiet areas for food and rest breaks
limiting the time workers spend in noisy areas by moving them to quiet work areas before their daily noise exposure levels are exceeded.

It is not always possible to reduce noise emissions for some machines and equipment, for example, large ball mills, angle grinders and explosive powered tools. In these cases, the operator should be protected through the best available means possible.

Following are some administrative noise control measures that can be used depending on the noise levels at the workplace:

Equipment maintenance programs

Maintaining machines and equipment in good condition will reduce noise. This should include modifications or additions such as noise mufflers, vibration isolators, or duct silencers.

'Buy quiet' program

Opportunities for implementing a 'buy quiet' program arise when:

plans are being made for the building and setting up of a workplace
expansion or refurbishment of the workplace is being considered
new plant and equipment is to be purchased or existing plant is to be replaced.

Job rotation

Job rotation involves changing tasks carried out by workers to prevent exposure to excessive noise.

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Personal hearing protectors and areas

Personal hearing protectors

A personal hearing protector is a device, or pair of devices, designed to be worn over, cover the ear canal entrance, or inserted in the ears of a person to protect their hearing. Personal hearing protectors should be used when levels of excessive noise cannot be reduced by using other control measures. Workers or others at the workplace should be:

supplied with personal hearing protectors of correct rating and suitable for the work conditions
instructed in their correct use
instructed to wear them when exposed to noise
monitored to ensure they wear hearing protection.

Personal hearing protectors should not be used as a substitute for engineering or administrative noise control measures.

Hearing protection areas

Areas where people may be exposed to excessive noise should be signposted as 'hearing protection areas' at every entry point to the areas. The boundaries of these areas should be clearly defined.

No person, including visitors, managers or supervisors, should enter a hearing protection area during normal operation unless they wear appropriate personal hearing protectors, regardless of how long the person spends in the hearing protection area.

Signs used to identify these areas should conform to AS 1319 Safety signs for the occupational environment (non-Queensland Government link). Correct selection can be confirmed with a supplier of workplace health and safety signs. Additional signs within the hearing protection areas may also be necessary.

Methods of achieving this include:

attaching prominent warning notices to tools and equipment to show that personal hearing protectors must be worn when operating them
providing written and verbal instructions on how to recognise circumstances in which personal hearing protectors are needed
effective supervision of identified 'hearing protection areas'.

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