Noise may lead to permanently impaired hearing, incurable damage to the inner ear. The risk of permanent hearing damage or hearing impairment is dependent on the strength and duration of the noise.
Hearing damage develops quickly over the first couple of years of exposure to noise. Therefore, it is important from the outset to protect your hearing by acknowledging the risk and attempting to reduce the noise. Many people do not find out that their hearing has been damaged until they become older.
Both tinnitus (ringing/buzzing in the ears) and hyperacusis (abnormal hypersensitivity to noise) often occur due to noise.
Noise can damage other things besides your hearing. Noise is also a stress factor and can cause elevated blood pressure and pulse, among other things. In the long term, it can contribute towards overloading and damage of the organism.
The limit for noise at work sites is 85 dB(A), measured on average over an eight-hour working day. Unnecessary noise must be avoided, even if the limit is not exceeded. The noise must be as low as is technically reasonable, and acoustic conditions must be satisfactory.
If there are powerful impulses in the noise, e.g. from impact tools, measurement of the noise must be increased by 5 dB(A) so that a genuine comparison can be made with the limit. Powerful impulses are impulses peaking at more than 115 dB(C) and occurring at least once a minute.
If the peak value exceeds 130-140 dB(C), your hearing may be damaged even if these noises are short and fairly few in number. Nobody may be exposed to peak values in excess of 137 dB(C).
The employer must ensure that noise is attenuated using technical arrangements. If this is not possible, he must limit the amount of time to which individuals are exposed to noise or organise work in some other way, e.g. by carrying out noisy work separately from other work. A combination of attenuation and administrative arrangements may also provide a solution.
If the noise load exceeds 80 dB(A), or if the noise is harmful or extremely unpleasant, the employer must provide ear defenders.
In instances where the noise load is at 85 dB(A) or above, or the peak values are at 137 dB(C) or above, the employer must ensure that suitable ear defenders are work from the moment work begins.
BFA Bygge & Anlæg recommends under all circumstances that ear defenders be worn between 80 and 85 dB(A) to be sure of not damaging hearing.
Ear defenders are only an emergency solution; for more information, see the section on ear defenders.
Examples of technical arrangements:
- Attenuate the noise at source, e.g. by turning off or stopping equipment which is not being used, and by avoiding striking metal against metal.
- Attenuate noise from noisy machinery, e.g. by having sound-absorbing materials in the driver’s cab in contract machinery, enclosing compressors, using sound locks, etc.
- Ensure that less noisy methods are used where possible, e.g. by blasting instead of using a drilling hammer.
- Limit noisy work e.g. by creating recesses for holes in concrete flooring instead of cutting them in afterwards, or by having steel bars supplied to set dimensions, thereby reducing noisy cutting.
- Choose quality tools and machinery which generate as little noise as possible.
Examples of other arrangements:
- Limit the amount of time spent in noisy areas. This can be done by having a number of people to carry out/share the work.
- As far as possible, always buy low-noise machinery.
- Plan work so that individual workers do not expose one another to noise unnecessarily.
- 4Developers and advisors can help to reduce noise considerably in the schedule for the Health and Safety Plan.
Be aware that the supplier has to provide information on the machine’s noise level if it generates noise in excess of 70 dB(A) at the operation site. Where relevant, the usage instructions must also provide information on setup and installation with a view to reducing noise. Relevant noise-attenuating arrangements (e.g. enclosure) and use of ear defenders must also be described.