What damage can noise cause?
Noise can have temporary and permanent effects.
Noise can affect the nerve cells in your inner ear, causing a temporary reduction in hearing. Most temporary hearing loss recovers in 24 hours under quiet conditions. There may be ringing or buzzing in your ear too (called tinnitus).
Repeated exposure to loud noise over time may cause permanent hearing loss. This is called noise-induced hearing loss, and it usually happens over many years. Noise-induced hearing loss reduces a person’s ability to hear high pitched sounds. How much hearing loss a person has depends on the noise level, how long they are exposed to it, and their susceptibility.
Noise-induced hearing loss can also come from sudden loud noises, like explosions, gun shots or heavy hammering. If the noise is loud enough the damage can be immediate.
Noise-induced hearing loss can't be repaired.
Noise exposure standard
Sound pressure level is measured in decibels (dB).
The Occupational Health and Safety Regulations 2017 (OHS Regulations) set a noise exposure standard for workplaces. If employees are exposed to noise that is above this standard, the workplace is too noisy.
Noise exposure measurements are taken at an employee's ear position.
The standard is in 2 parts:
- 85 dB(A) averaged over an 8-hour period
- a maximum (peak) noise level of 140 dB(C)
Is noise a problem in your workplace?
Noise is a problem in the workplace when:
- employees have to raise their voice to communicate at a distance of 1 metre
- employees have a temporary reduction in hearing or ringing in the ears after leaving work for the day
See the Noise compliance code for a checklist to help identify noise hazards, and to understand how to calculate if noise standards are exceeded in your workplace.
If it's not clear if there is a noise problem, some spot noise measurements may help. You may need to get a noise assessment done by a qualified person.
Below are some common noise sources and their approximate noise levels. Actual levels in the workplace may vary a lot from these.
Table: equivalent noise exposures
Typical sound level in dB | Source |
|---|---|
140 | Jet engine at 30m (pain can be felt at this threshold) |
130 | Rivet hammer (pain can be felt at this threshold) |
120 | Rock drill |
110 | Chainsaw Angle grinding |
100 | Sheet-metal workshop |
90 | Lawn-mower |
85 | Front-end loader Listening to a personal music player in a quiet room |
80 | Kerbside heavy traffic Lathe Welding |
70 | Loud conversation |
60 | Normal conversation |
40 | Quiet radio music |
30 | Whispering |
20 | Quiet urban room |
10 | Rustling leaves |
0 | Hearing threshold |
Controlling noise risk
Apply risk controls
The OHS Regulations have specific requirements for the control of noise above the exposure standard. They set out specified risk control measures, to be used in order. Work through the following list to control noise risks. This is called the hierarchy of control.
- Eliminate the source of the noise. You must always try to do this first. For example, stop using a noisy machine.
- Use substitution or engineering controls to reduce noise exposure. You may need a combination of these measures. Substitution means using quieter plant or processes - for example replace hammering nails with a process for gluing wood. An example of an engineering control is building an enclosure around a noise source.
- Use administrative controls (work systems) to reduce noise exposure. For example, rotate employees between noisy and quiet jobs.
- Provide hearing protectors (like earmuffs or earplugs) to reduce noise exposure.
Revise risk controls
Review your risk controls to make sure they are working properly. You must review and, if needed revise them if, for example:
- there are changes to the way work is done, such as changes to plant, that could cause exposure to noise above the exposure standard
- there is a report of hearing loss
- a notifiable incident occurs where there has been exposure to noise above the exposure standard
- a HSR requests
Hearing tests
If an employee needs hearing protection to reduce their exposure below the standard, you must provide audiometric testing within three months of when they start the relevant work, and at least every two years. You must also provide testing upon a reasonable request by the employee's health and safety representative.
Where hearing protectors are required you must clearly identify by signs or labelling when and where the protectors are to be worn.
Health and safety legal duties
The Occupational Health and Safety Act 2004 sets out duties in relation to health and safety in the workplace. The OHS Regulations also have specific duties about noise risk. See the Compliance code: Noise for full detail of duties relating to noise for:
- employers
- self-employed people
- employees
- manufacturers and designers of plant (machinery and equipment)
- suppliers of plant
- persons who install, erect or commission plant