Before introducing hearing protection, there are other steps to be taken to control noise exposure. Starting in the planning stages, carefully selected equipment and processes can eliminate or significantly reduce noise at source.
Consider what changes could be made in the workplace to minimise noise. Following the hie=rarchy of controls, measures should first seek to eliminate or substitute noisy tasks and equipment, then engineering and administrative controls can be implemented to reduce exposure further. As the last step, hearing protection may be used to bring personal exposure to a safe level.
Elimination and substitution
When planning for a job, select equipment and design processes to eliminate or reduce noise wherever possible. Consider whether a task could be carried out in a quieter way. This may mean changing a procedure or specifying quieter machinery and equipment.
Introducing a low-noise purchasing policy is an effective way of reducing noise without making any other modifications or using hearing protection. Specify safe sound output levels for machinery and equipment and ask the supplier about likely noise levels in your particular application.
Engineering controls
Engineering controls include modifying equipment and setting up the workplace to manage noise exposure. Adding damping material and isolating machinery helps to cut out vibration noise. Reduce impulse noise by avoiding metal-on-metal impacts and decreasing drop heights. Pneumatic silencers can be fitted to air exhausts and blowing nozzles. Regular maintenance of machinery and equipment is also important to keep noise levels to a minimum.
Machine enclosures and sound barriers change the way noise travels through the air. Enclosing or blocking the direct path of sounds limits noise exposure for people working nearby.
Administrative controls
Changing the way work is carried out can also help to control noise exposure. Design the workflow to keep noise-emitting machinery away from areas where workers spend the most time. Limit how long workers are exposed to noise for: halving the time spent in a noisy area decreases exposure by 3 dB.
Set up hearing protection zones to isolate noise within specific areas. All noise-emitting tasks are carried out within these zones, in which workers are required to wear appropriate hearing protection. Enclosures and barriers are used to keep noise out of other parts of the workplace.
Selecting hearing protection
If exposure remains at a harmful level after implementing other control measures, personal hearing protection can be worn to reduce residual noise to a safe level. The aim when selecting hearing protection is to achieve an average exposure of 80 dB for the wearer.
Noise exposure limits and control requirements vary by region. It is important to check local legislation prior to selecting hearing protection equipment.
Hearing protectors must be correctly fitted, well-maintained and compatible with other equipment to provide the intended level of attenuation. Select an SNR level that provides adequate attenuation without overprotecting the wearer. Training should cover how to fit and maintain hearing protectors, as well as when they are required to be worn.
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