Noise

(refer to disclaimer)

Information

Present in most workplaces is exposure to noise levels that are loud and/or for short or long periods will result in injury to employees in the workplace.

It is important to realise that loud noise may also tend to obscure warning signals or alarms, eg. overhead cranes. Noise can also interfere with concentration and over a period can cause fatigue.

What is Noise?

Noise is the label commonly given to sound waves within the workplace and there are two ways this sound energy can be measured:

Loudness – this is magnitude of pressure variations in the air measured by decibels (dB)

Frequency – this is the rate of pressure variations, measured in terms of frequency as Hertz (Hz).

These terms cover a very complex range of physics/physiological factors and to make dealing with this exposure easier, a special unit called A weighted decibel scale is used (dB[A]).

This allows a scale to be drawn.

What are my Legislative Obligations?

Under legislation, an exposure level, often referred to as the ACTION LEVEL: - an eight hour exposure to:

1. equivalent continuous A weighted sound pressure level of 85dB(A).

2. a peak sound pressure level of 140dB(A).

The effect of these provisions are that if you fall into this action level criteria; a noise assessment must be carried out.

In addition, where employees wear P.P.E., ie. ear muffs or ear plugs, they are to have hearing tests every 2 years as a minimum.

Records are to be kept for a minimum of 20 years.

What are Results of Excessive Noise?

There are a number of conditions that can be caused by exposure to excessive noise, ie. exposure to noise above the Action Level:

• Tinnitus – ringing in ears.
• Threshold Shift – Temporary/Permanent
• Industrial Deafness
• Acoustic Trauma
• Stress
• Sleeplessness
• Fatigue

In general terms these will be compensable injures with potential for lump sum payments subject to a threshold test.

What are Accident Statistics?

Injuries arising in the workplace as a result of exposure to excessive noise are classified as an Occupational Disease in the reporting regime in Australia and it is difficult to assess the full picture.

In general terms, claims arising from exposure to excessive noise according to NOHSC is one of the most common injuries in the workplace.

What Action is Required?

This means you must have an assessment done to measure noise levels in your workplace.

This assessment must be carried out by a competent person and be conducted in accordance with relevant standards (AS 1269 and AS 2659).

Records of assessment are to be kept for a minimum of five years.

• What are the sources of noise in the workplace?
• Which work process are noisy?
• Determine which employees are likely to be exposed to excessive noise.
• Which control measures are available to reduce the noise exposure

Develop a Hearing Conservation Program.

• The employer, in consultation with employees should develop a written noise control policy and plan of action to control noise levels.
• Targets for noise exposure and peak noise levels in the workplace.
• Design for new plant/processes.
• Controls to be used in temporary work areas and casual situations.
• Agreements with contractors.

Implement Hierarchy of Control

If it has been established that it is necessary to reduce the noise levels in the workplace then the Hierarchy of Controls must be applied.

Engineering control measures – includes silencing the plant either by eliminating or replacing the machine or its operation or enclosing noisy plant or the operator in sound enclosures.

Administrative control measures – when it is not reasonably practicable to control the noise solely through engineering measures, job rotation, job redesign or rosters so that few employees as possible are exposed to noisy operations or duration of exposure is restricted.

Personal Hearing Protection – when engineering and administrative do not reduce the exposure. These include enclosing helmets, plugs and ear muffs.

Example

In a cardboard factory the strip of cardboard was being cut by a knife blade.

This blade was operated by compressed air cylinder that caused the knife to chop vertically through the board with great force and speed.

This process generated continual noise that was above the action level.

The solution was to redesign this process as follows:

• The knife was replaced by blade which travelled horizontally across the strip powered by an electric motor and pulley strap.
• The noise level is now well below the Action Level.

NEED MORE INFORMATION

• about relevant Codes of Practice
• about relevant Australian Standards
• other examples of accidents
• other relevant information

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