Protecting employees from exposure to noise
Employers have a duty to protect the health and safety of their employees. This duty includes protecting employees from exposure to noise. The Occupational Health and Safety Regulations 2017 (OHS Regulations) set a noise exposure standard measured in units called decibels (dB). The noise exposure standard is an 8-hour average of 85 dB(A) and a peak noise level of 140 dB(C) at the employee's ear position.
Exposure to noise that exceeds the standard is considered dangerous to employees' hearing. Employers must ensure employees' exposure to noise does not exceed the noise exposure standard.
If there is uncertainty about whether noise exposure exceeds or may exceed the standard, employers must determine an employee's exposure to noise in the workplace. When determining noise exposure, employers must not take into account the effect of any hearing protectors employees may be using.
Employers must take into account:
- the level of noise to which employees are exposed
- the duration of the exposure
- plant and other sources of noise at the workplace
- systems of work at the workplace
- any other relevant factors
Information about employers' duties is available on the WorkSafe website, including the Noise compliance code. The Noise compliance code provides practical guidance on how to comply with obligations under Victoria’s occupational health and safety legislation to manage risks associated with workplace noise exposure.
Use the hierarchy of control
The hierarchy of control is a step-by-step approach to eliminating or reducing risks. It ranks risk controls from the highest level of protection and reliability through to the lowest.
Employers must control noise in line with the following hierarchy of control measures:
- eliminate the source of noise
- substitute noisy plant with quieter plant or processes, isolate the plant or use engineering controls
- use administrative controls
- provide hearing protection
Employers must apply each level of the hierarchy so far as reasonably practicable before moving down to the next control measure. This means employers cannot go straight to hearing protection to control the noise without applying the higher-level control measures, so far as reasonably practicable.
It is often necessary to use a combination of control measures to effectively control noise.
When hearing protectors are required
Employers must provide hearing protection when employees' exposure to noise still exceeds the exposure standard after applying the higher level controls in the hierarchy of control.
Hearing protection is considered the least effective and least reliable control measure. This is because:
- it does not reduce noise at the source
- it is often not fitted correctly and not always worn when required
- it places an obligation on and relies on employee being responsible for their own safety at work
- some types of hearing protection may result in over-protection. This can isolate wearers from their surroundings and make communication difficult. Wearers might not hear warning signals such as sirens or reversing forklifts
- hearing protectors can be uncomfortable when worn for prolonged periods. This may make employees less likely to use them
- ear plugs may present hygiene issues and potential ear infections
Types of hearing protectors
Earmuffs, earplugs and ear canal caps are common types of hearing protectors.
Earmuffs
Earmuffs fit most people, are hygienic, easy to fit correctly and suitable for use in dirty areas. Earmuffs are also suitable for employees with medical conditions that do not allow them to insert earplugs into their ears.
However, earmuffs may be uncomfortable to wear for prolonged periods due to the weight and clamping force of the headband.
Earplugs
Earplugs come in different styles and different materials. Types of earplugs include those:
- made from expandable foam
- made from pre-moulded reusable material
- custom moulded to an employee’s ear canal
Earplugs tend to be more comfortable than earmuffs when used for long periods, particularly in hot or humid environments. The level of protection from earplugs is highly dependent on achieving a good fit.
Expandable foam earplugs are rolled into a thin tube and inserted into the ear canal. Using this type of earplug may present hygiene issues in dirty work environments.
Reusable earplugs are usually made of silicone or similar materials and are inserted or pushed into the ear canal. These plugs are washable and can be used in dirty environments as they do not need to be handled or rolled like expandable foam plugs. Custom-moulded earplugs are moulded specifically for the wearer's ear canal. This means they provide a high level of protection.
Ear canal caps
Ear canal caps are usually on a headband and seal the entrance to the ear canal. They are not inserted into the ear canal. Ear canal caps are usually more convenient when they have to be taken on and off, for example, when passing through noisy areas or being in noisy areas for very short periods of time). However, ear canal caps generally provide less noise protection than other types of hearing protectors.
Selection of hearing protectors
It is important to ensure hearing protection provides adequate protection and is worn at all times in noisy areas. Hearing protectors should not reduce noise exposure much below 75 dBA because of the problems of over-protection.
The following factors need to be considered when selecting hearing protectors:
- level of noise reduction, or attenuation, provided or required
- compliance with AS/NZS 1270:2002, Acoustics – Hearing protectors
- compatibility with job requirements such as working in hot environments
- use of other protective equipment that may affect the hearing protector. For example, helmets and goggles
- comfort for the wearer to ensure that they are worn and fitted properly
- hygiene and the potential for ear infections in unhygienic or dirty work environments
- safety considerations including overprotection and the ability to hear warning signals
Selection of hearing protectors based on noise reduction (attenuation) required
The main methods of selecting a hearing protector include the:
- octave band method
- SLC80 method
- the classification method
These methods are described in AS/NZS 1269.3:2005 – Occupational noise management – Part 3: Hearing protector program.
Of these, the classification method, is the simplest and most widely used. The octave method may be more suitable if there is a dominant noise frequency present.
The classification method rates hearing protectors from Class 1 to 5. To use this method, it is necessary to know employees’ eight-hour exposure level (LAeq8h). Once the exposure level is known, select the class of protector as indicated in the table. The following table also shows the corresponding SLC80 values.
Table 1. Relationship between class and SLC80 values of hearing protector
Class | SLC80 range | 8-hr Exposure LAeq8hr dB(A) |
|---|---|---|
1 | 10 - 13 | Less than 90 |
2 | 14 - 17 | 90 to less than 95 |
3 | 18 - 21 | 95 to less than 100 |
4 | 22 - 25 | 100 to less than 105 |
5 | 26 or greater | 105 to less than 110 |
The Class, SLC80 value and the noise reduction data at various frequencies for the octave method are usually on or in the packaging or on the hearing protector itself.
Earplugs and earmuffs used together
If a very high level of protection is required, earplugs and earmuffs can be used in combination. Combining earplugs and earmuffs can increase noise reduction by about 5 dB. It is important to note that the total noise reduction is not the sum of the individual hearing protectors. As a general rule, add 5 dB to the higher value to estimate the total noise reduction.
For example:
Protector A - SLC80 = 26 dB
Ear plug - SLC80 = 22 dB
Protector A and earplug worn together = 31 dB
Information on the combined noise reduction may be available from the manufacturer.
Wearing hearing protectors
Employers should ensure employees wear hearing protectors:
- when and where they are needed
- for the entire time they are needed
Removing hearing protectors even for short periods can significantly decrease the 'effective' protection. Table 2 illustrates how the protection provided by a hearing protector rated at 30dB is affected when it is not worn for short periods.
Table 2. Decreased 'effective' protection
Percentage of exposure time worn | Effective protection (dB(A)) |
|---|---|
100% | 30 |
98.60% | 18 |
84% | 8 |
As shown, even if hearing protection is worn 98.6% of the exposure time, it only provides 18 dB overall reduction, not 30 dB. Similarly, if protection is worn for 84% of the time, it only provides an effective reduction of 8 dB instead of 30 dB.
This means it is better to select a hearing protector that is comfortable and likely to be worn during the entire exposure rather than one that provides high protection but is uncomfortable and likely to be removed for short periods.
Involving employees in the selection of hearing protectors where they are able to personally trial and choose their own device may help ensure the use of hearing protectors. Managers and supervisors should also encourage the use of hearing protectors by setting an example themselves. They should provide supervision to ensure employees wear hearing protectors at all times where required.
Education and training
Employers must provide employees with the information, instruction, training and supervision they need to perform their work safely and without risk to their health.
Employers should provide employees with instructions on how to correctly fit, use, clean, maintain and store their hearing protectors. The instructions should be in line with the manufacturer's instructions.
Hearing protection warning signs
Employers must clearly identify when and where hearing protectors are to be worn. Identification may include signposting areas and rooms or by labelling plant.
Audiometric (hearing) testing
If hearing protectors are required to control noise exposure below the standard, then audiometric testing (hearing tests) is required.