Noise

Most people’s ears are very sensitive to noise.  When sound enters the outer ear, it vibrates the eardrum. These vibrations pass into the inner ear via tiny bones where eventually delicate nerve cells like blades of grass convert the vibrations into messages which are sent to the brain. Noise can affect these nerve cells causing a temporary reduction in hearing.

Most temporary hearing loss recovers within 24 hours under quiet conditions and may be accompanied by a ringing in the ear, called tinnitus. If people’s ears are exposed to loud noise continually over a period of time, the nerve cells in the inner ear may eventually die and not respond to sound. This condition is called noise induced hearing loss and usually occurs gradually over many years like hearing loss due to ageing.  Noise induced hearing loss reduces a person’s ability to hear high pitched sounds.

Hearing loss affects people’s ability to communicate and keep in touch with the world around them, and affected people often suffer a feeling of isolation. Some people will avoid contact with others because they are embarrassed or anxious about not hearing properly. This can affect their social and work life, and may also place pressure on family life. Hearing loss may decrease their efficiency at work. In addition, accidents may occur when instructions or warning signals cannot be heard or are not understood properly. If severe enough and the result of workplace noise they may also submit a workplace injury claim.

There is a growing body of evidence that suggests exposure to noise is a cause of non-auditory damage in the cardio-vascular, endocrine, metabolic, gastro-intestinal and neurological systems. Performance in reading, writing and listening tasks are also affected by noise, as is concentration. Both sudden bursts of noise and continuous noise are known to affect these activities. While some noise is unlikely to cause hearing loss, it can be an annoyance and reduce the effectiveness of those exposed to it.

The disability sector is varied and diverse. Whilst work tasks involved in the majority of services offered would not result in long term noise exposure the work undertaken by Disability Enterprises or clients involved in work experience or open employment may result in staff being exposed to high levels of noise over an extended period.

Organisations with a commitment to risk management have the potential to eliminate or reduce the risks associated with noise induced hearing loss.

Legislative Context

Service providers in the Disability Sector are obliged to apply the principles of the NSW Disability Services Act and also to meet their obligations as employers under the Work Health and Safety Legislation.  The Model Code of Practice on Managing Noise and Preventing Hearing Loss at Work also provides guidance material regarding how service providers can meet their obligations under the WHS legislation. 

A new feature of the Work Health and Safety legislation is the requirement to undertake hearing assessments.

Where hearing protection is provided to protect workers from noise which exceeds noise standards audiometric testing is required.  Audiometric testing must be provided within three months of the worker commencing work. Starting the audiometric testing before people are exposed to hazardous noise (such as new starters or those changing jobs) provides a baseline as a reference for future audiometric test results. Regular follow-up tests must be carried out at least every two years. These should be undertaken well into the work shift so that any temporary hearing loss can be picked up.

More frequent audiometric testing (e.g. every six months) may be needed if exposures are at a high LAeq,8h, which is equal or greater than 100 dB(A).

Before introducing an audiometric testing program, you must consult with your workers and their health and safety representatives. It is important that your workers understand that the aim of the testing is to evaluate the effectiveness of control measures to protect their hearing.

Audiometric testing and assessment of audiograms should be carried out by competent persons in accordance with the procedures in AS/NZS 1269.4:2005 - Occupational noise management - Auditory assessment.

Workers should be given the results of audiometric testing accompanied by a written explanation of the meaning and implications. Only with the consent of the worker should you provide their results to other parties. Unidentifiable individual results and group data should be made available to health and safety representatives of the worker’s work group.

The reasons for any changes in hearing levels over time should be thoroughly investigated.

When temporary or permanent threshold shifts are revealed through audiometric assessments or a worker reports a recent diagnosis of tinnitus, you must review your control measures to determine whether more effective control measures can be implemented so that your workers do not have to rely on personal hearing protectors.

If the worker is to continue using personal hearing protectors, you should:

• verify that the nominal performance of the worker’s personal hearing protector is adequate for the level of exposure to noise
• examine the protector carefully and ensure it is not damaged
• check the protector fits the worker closely with no leakage paths for noise
• ask the worker if they have any difficulty using the protector
• check the worker uses the protector correctly and consistently whilst performing their work.

If workers are found to have sufficient hearing loss to interfere with the safe performance of their work, all reasonably practicable steps should be taken to modify the work environment. This may include providing:

• volume control on equipment such as telephones
• acoustically treated meeting areas with low noise and low sound reflections
• supplementary visual warning signals
• alternative work for the worker if other measures do not remedy the situation.

Monitoring hearing with regular audiometric testing is recommended in situations where workers are exposed to:

• any of the ototoxic substances listed in Appendix A where the airborne exposure (without regard to respiratory protection worn) is greater than 50 per cent of the national exposure standard for the substance, regardless of the noise level
• ototoxic substances at any level and noise with LAeq,8h greater than 80 dB(A) or LC,peak greater than 135 dB(C)
• hand-arm vibration at any level and noise with LAeq,8h greater than 80 dB(A) or LC,peak greater than 135 dB(C).

Risk Management and Noise Management

Under the Work Health and Safety Regulation PCBUs must manage risk to health and safety relating to heraing loss associated with noise and must ensure that that the noise that a worker is exposed to at the workplace does not exceed the exposure stnadard for noise.  Designers, manufactuerers etc must ensure noise emissions are as low as possible and provide adequate info on the noise emission values of the plant. 

Components of Risk Management – Reference Source ‘WorkCover NSW Hazpak Guide’

1. IDENTIFY – the risks for noise exposure when introducing new plant or equipment, designing a new work tasks or assessing a particular activity.
2. ASSESS – the risk, its likelihood of occurring, and when it does occur what is the consequence i.e. what injury can occur to the person.  You will then come up with a risk ranking
3. CONTROL – once you have completed the assessment, you need to identify controls or measures to either eliminate the risk or reduce it to a low as reasonably practicable (ALARP) 
4. REVIEW – controls and procedures, where noise exposure is a component of ongoing activities to ensure exposure levels are below that specified in the Regulation.  Refer to Clause 49 OHS Regulations 

A consultative approach may identify the need for noise assessments in the workplace. Many activities and tasks will generate noise but an assessment will determine the exact level of exposure and potential risk.  Risk assessment is an integral part of successful risk management and should take place as often as necessary to ensure that appropriate controls are in place.

Noise induced hearing loss may result from working in a noisy environment where the cumulative exposure is greater than 85 decibels over an 8 hour day or when exposed to impact noise levels of 140 decibels or greater.

Consultation between management and workers is an important part of the hazard identification process.  Where workers report that they have to raise their voice to communicate at a distance of 1 metre;  that they experience a temporary reduction in hearing or ringing in the ears after leaving work for the day; or they ask to use hearing protectors during the work day, then noise may be a problem at your workplace and may require a proper assessment.

Once a hazard is identified it is important to assess the risk level. This includes assessing how likely is it that the hazard will cause hearing loss and how severe the hearing loss may be if it occurred.

You cannot recover from noise-induced hearing loss and hearing aids do not produce the same quality of hearing.

A risk assessment would normally take the form of a noise assessment.  A noise assessment may be simple or complex, depending on what’s causing the noise and how the job is done. The noise assessment should be done during a typical workday and must determine:

• the level of noise; and
• how long employees are exposed.
• An assessment must take into account:
• plant and other sources of noise in operation;
• how the job is done (ie the systems of work); and
• any other relevant factors.

Where employees’ exposure to noise varies quite a bit from day to day, the assessment should take that into account. As a general rule, the worst case scenario should also be taken into account.  Measurements must be taken at the employee’s ear position using suitable equipment that has been calibrated. The measurements need to be taken for a period of time that is representative of the process, activity or work pattern being assessed. The period should take into account significant variations in the level and duration of the exposure and may require measurements to be taken over a full shift.

The Hierarchy of Control – ‘as low as reasonably practicable’

There are six ways to deal with hazards or control risks to health and safety

1. Eliminate - the hazard or risk, get rid of noisy equipment or processes by outsourcing etc
2. Substitute - substitute the hazard for something that gives rise to a less noise by changing material.
3. Isolation – isolate the hazard, separate the noise source in time or space from the person at risk i.e. using shields or barriers
4. Engineer - Design in safety, by fitting noise absorbing material
5. Administration - Change work methods, rotate staff through noisy work areas etc.
6. Personal protective equipment - this should not be the only control used and should only be applied as a last resort.

High Noise levels may be eliminated or minimised by:

Risk controls can be immediate, short to long term.  You need to monitor and review your controls on a continual basis and communicate/consult the results with your staff

Ongoing monitoring and review is an integral part of risk management. After applying controls to eliminate or reduce identified hazards, it is important to assess their effectiveness. Some controls might create other, unforseen hazards. It is important to continue to consult with everybody involved.

Risk management need not be costly. Many simple and inexpensive measures can greatly reduce risk. You need to consider the potential exposure of your organisation if you do not actively manage noise risks.

Communication and consultation is the key element to good risk management practice.  Ensure you document each stage of your risk management process i.e. how, what, when and by whom to achieve a positive outcome

Training content

Topics that should be included in a training program aimed at prevention of noise-induced hearing loss and tinnitus include:

• the effects of noise on hearing
• the social handicaps of noise-induced hearing loss
• the rationale for the relevant provisions of the OHS Regulation 2001
• the statutory responsibilities of employers and employees
• an overview of the workplace noise control policy and program of action
• the nature and location of noise hazards in the workplace associated with the technology, plant and/or work practices employees use in the course of their jobs
• the nature of the general noise control measures which are in use or are planned
• the specific control measures which are necessary in relation to each employee’s own job. (As appropriate, this should include instruction in the correct use and maintenance of exhaust silencers, enclosures and other measures which minimize noise levels.)
• when and how to use personal hearing protectors provided including selection, fitting, proper care and maintenance
• the arrangements for reporting defects in plant or the workplace which are likely to cause exposure to excessive noise
• the purpose and nature of audiometric testing.

DEFINITIONS

A-weighting refers to a standardised frequency response used in sound measuring instruments as specified in Australian Standard AS 1259.1. Note: Historically it was developed to model the human ear response at low sound levels. However A-weighting is now frequently specified for measuring sounds irrespective of level and studies have shown a relationship between the long-term exposure to A-weighted sound pressure levels and hearing damage risk. 1

C-weighting refers to a standardised frequency response used in sound measuring instruments, specified in Australian Standard AS 1259.11.

dB means the abbreviation for decibel. Also see definition for decibel.

dB(A) means A-weighted sound pressure level in decibels. Also see definition for A-weighting.

dB(C) means C-weighted sound pressure level in decibels. Also see definition for C-weighting.

Decibel is the unit used to indicate the relative magnitude of sound pressure level and other acoustical quantities. The range of sound pressures commonly encountered is very large so a logarithmic scale is used. The decibel is the unit used on this scale and is abbreviated to 'dB'. On the decibel scale, the threshold of hearing occurs at a sound pressure level of about 0 dB and the threshold of pain occurs at about 120 dB. As the decibel is also used to describe the level of other quantities, such as sound power and vibration acceleration, it is always necessary to refer to the specific quantity being measured, for example, LAeq,8h or LC,peak. 

CORE ELEMENTS OF NOISE MANAGEMENT  LEGISLATION

Occupational Health and Safety Act 2000

The OHS Act 2000 describes general duties and legal obligations in regard to OHS matters. It includes both employee and employer responsibilities. Section 8 requires employers, and therefore all managers, to ensure the health, safety and welfare of their employees, and of people visiting or working at their place of work who are not employees. Relevant requirements include:

• Maintaining places of work in a safe condition,
• Ensuring the safe use, handling and transport of plant and substances,
• Providing and maintaining safe working environments and systems of work,
• Providing the information, instruction, training and supervision necessary to ensure the health and safety of employees.

There is also a general duty under Section 13 for employers/managers to consult with employees about OHS matters, so that employees can contribute to decisions affecting their health, safety and welfare.

Section 20 requires employees to take reasonable care of the health and safety of others who may be affected by their acts or omissions and to cooperate with employers in their efforts to comply with OHS requirements.

Occupational Health and Safety Regulation 2001

Under Part 4.3 of the OH&S Regulation 2001, risk control measures are required to be implemented by an employer if a person is exposed to noise levels that:

1. Exceed an 8-hour noise level equivalent to 85 dB(A), or
2. Peak at more than 140 db(C).

In order to meet this requirement the employer must ensure that:

1. The measurement is to be made in accordance with AS/NZS 1269.1:1998 Occupational Noise Management Part 1: Measurement and assessment of noise emission and exposure, and
2. Exposure to noise is taken to be measured at the position of the ears of a person, or at an equivalent of that position, and
3. The measurement is to be made on the assumption that the person is not wearing any device to protect himself or herself from noise.

New South Wales Code of Practice on Noise Management and Protection of Hearing at Work 2004

This Code of Practice provides practical advice on how to meet the requirements of the regulation for the identification, assessment and control of risks arising from noise exposure in workplaces.

The Code of Practice is an approved code of practice under Section 43 of the OHS

Act and failure to comply with the code of practice can be used as evidence in the event of prosecution.

The Code of Practice aims to prevent the occurrence of injury and/or reduce the severity of injuries resulting from noise exposure in workplaces

Note: This material has been prepared using the best information available. You should always check current legislation in relation to your own circumstances actions you may need to take to ensure you have complied with the law.