Occupational noise is a widespread risk factor, with a strong evidence base linking it to hearing loss. It is also distinct from environmental noise, in that it is by definition associated with the workplace, and is therefore the responsibility of employers as well as individuals.
High levels of occupational noise exposure pose a significant risk to health, safety, and hearing acuity. It has been estimated that worldwide, 16% to 24% of hearing impairment is work-related. 1 in 6 Australians are affected by hearing loss to varying degrees – a figure that is expected to rise to 1 in 4 as the country’s population ages.
When it comes to the workplace, there are a number of laws that must be adhered to by employers and employees in order to lessen the impact the high decibel environments have on an individual’s hearing.
Occupational noise induced hearing loss (NIHL) is the main outcome of exposure to occupational noise.
Occupational NIHL develops insidiously over time and is the result of continuous or intermittent noise exposure and duration. The time lag that occurs between work-related hearing damage and the presentation of symptoms can be several years, depending on the duration and intensity of the noise exposure.
Threshold shift is the precursor of NIHL. It corresponds to a permanent increase in the threshold of hearing that may be accompanied by tinnitus. Because hearing impairment is usually gradual, the affected worker will not notice changes in hearing ability until a large threshold shift has occurred.
Noise-induced hearing impairment occurs predominantly at higher frequencies (3000−6000 Hz), with the largest effect at 4000 Hz.
NIHL is irreversible and increases in severity with continued exposure.
The consequences of NIHL include: social isolation, impaired communication with coworkers and family, decreased ability to monitor the work environment (warning signals, equipment sounds), increased injuries from impaired communication and isolation, anxiety, irritability, decreased self-esteem, lost productivity, expenses for workers’ compensation and hearing aids.
Some of the highest occupational noise exposures and hearing loss risks can be found among mining and construction workers.
Construction workers and hearing protection
Construction workers are exposed to many different sources of noise, many of which change throughout the day and depending on the site and job on which they are working.
When it comes to the use of hearing protection, there are many unique factors affecting a construction worker’s use of hearing protection devices.
This includes the high variability of noise exposure as workers move in and out of noisy areas, exposure to complex combinations of noise sources, employment at multiple job sites each day, and the likelihood of being self-employed, placing the onus on the worker to take greater responsibility for their own health and safety.
Other causes of irregular use of hearing protection include difficulties with communication and discomfort. The insidious nature of NIHL and the fact that it is often not noticed until the loss is significant, means the risk can be far less obvious, thereby weakening the motivation of the individual to use hearing protection.
Occupational noise survey
A noise survey takes noise measurements throughout an entire work location, plant or section to identify noisy areas. Noise surveys provide very useful information which enables employers to to identify:
- Areas where employees are likely to be exposed to harmful levels of noise and personal dosimetry may be needed.
- Machines and equipment which generate harmful levels of noise.
- Employees who might be exposed to unacceptable noise levels.
- Noise control options to reduce noise exposure.
A noise survey is conducted in areas where noise exposure is likely to be hazardous. A sound level meter is usually used for this purpose.
The need for measuring the employees’ noise exposure arises when noise survey indicates the possibility that the employees may be exposed to noise exceeding the noise exposure limits set by noise regulations or the limits set by the company. Personal noise exposure of employees is measured using a noise dosimeter.
A noise dosimeter is worn by an employee during the entire or part of a shift. The reliability of the noise data will depend on the employee’s cooperation in the proper use of the dosimeter.
Here are some helpful tips to ensure your employee’s co-operation with noise dosimetry:
- Inform the employees about the purpose of measurement.
- Explain the importance of the accuracy of noise data in assessing the need for noise control.
- Emphasise the importance of wearing it all the time during the measurement period.
- Explain the consequences of tampering with the microphone – shouting in it, using it to knock on doors, etc.
CHP’s WorkSafe Noise Officers will work with you to ensure minimum disruption to normal daily activities when conducting an onsite Noise Survey.
Contact us to find out more…