3. Noise assessments
3.1 When should a noise assessment be done?
3.2 What is the aim of a noise assessment?
3.3 How often should noise assessments be carried out?
3.4 How to carry out a noise assessment
A noise assessment may be simple or quite complex, depending on the type of workplace, the number of workers and the information already available regarding noise exposure levels. The detail and accuracy needed will depend on individual circumstances.
3.1 When should a noise assessment be done?
Obligation holders should carry out noise assessments when workers and others may be exposed to risks from noise levels above LAeq,8h 85 dB(A) and/or LC,peak 140 dB(C), i.e. excessive noise. If noise exposure is marginally below LAeq,8h 85 dB(A) the noise levels should be reassessed whenever any changes that may increase noise exposure are made.
A noise hazard identification checklist is supplied in appendix 3. This checklist can be used as a preliminary assessment to indicate whether a more detailed assessment is required.
3.2 What is the aim of a noise assessment?
Noise assessments vary depending on the severity of the risks at the workplace. The general aim of a noise assessment is to:
- identify all persons likely to be exposed to excessive noise. Generally, this will involve the evaluation of LAeq,8h and measurements of peak noise levels where relevant;
- obtain information on noise sources and associated work practices. This information will help decide what measures should be taken to reduce noise levels;
- check the effectiveness of measures taken to reduce noise exposure or the risks from noise exposure. If a base-line has been established in a more comprehensive assessment and there has been no change at the workplace it may be possible to restrict future surveys. These surveys would measure noise levels at a few defined positions and under a restricted range of working or loading conditions of the equipment involved;
- help choose appropriate personal hearing protectors for persons exposed to risks from excessive noise; and
- define hearing protection areas at work.
3.3 How often should noise assessments be carried out?
The period between carrying out noise assessments can be decided by employers in consultation with workers. Noise assessments should be repeated at least every five years or whenever there is:
- installation, adjustment or removal of plant;
- any change in workload or equipment operating conditions likely to cause a significant change in noise levels;
- a change in building structure likely to affect noise levels; or
- modification of working arrangements affecting the length of time workers are exposed to noise.
Noise assessment records should be made available in a consistent format and be available for inspections by management, workers and any workplace health and safety representatives and relevant a uthorities. Where possible, the records should be kept at or near the workplace to which they apply. Where this is not possible, for example, at a workplace where construction work is being performed, the records should be kept available at an appointed office.
3.4 How to carry out a noise assessment.
This depends on the type of workplace, the number of persons at risk from noise exposure and the information already available on noise levels at the workplace.
If there is no prior information available, an assessment should establish if there are excessive noise levels at the workplace.
In some cases, more complex measurements are required to determine a person’s exposure to noise with acceptable accuracy, or for the selection of personal hearing protectors. For example, octave band analysis13of the noise may be desirable if it contains intense tonal, high frequency or low frequency components. Other situations which may warrant more complex measurement include workplaces with variable noise levels over the period of a day (or longer period) and jobs where workers move in and out of areas where excessive noise exists.
More detailed information on noise measurement and recording is available in part 1 of AS/NZS 1269 Occupational noise management (non-Queensland Government link)
A person who carries out a noise assessment should meet the competency requirements of Appendix A of part 1 of AS/NZS 1269 including:
- knowledge of the aim of an assessment
- the correct way of using instruments and their limitations
- the normal operating conditions of the workplace
- relevant Australian Standards and statutory requirements
Information about instruments used in the monitoring of noise at the workplace is given in appendix 4.
Results of noise assessments
Where a noise assessment shows that workers are exposed to excessive noise, steps to prevent the risks from such noise exposure must be taken.
Low level noise assessment
When noise levels may fall in the LAeq,8h range of 55 to 85 dB(A) and workers or others have indicated that a problem exists with this level of noise, a noise assessment should be carried out. Where the assessment shows a risk exists, elimination, engineering or administrative control measures should be implemented.
13 'octave band analysis' means analysis of the frequency content of noise into octave bands.
Last updated 21 August 2008