European Week for Safety and Health at Work
European Week 'Stop that noise!' 24 to 28 October 2005
Almost 1 in 3 employees in the EU are exposed to noise for more than a quarter of their work time. Continuous exposure to loud noises, i.e. more than 80 decibels (db(A)), may damage the hearing. The term noise is used to mean undesirable or damaging sound. The two main measures of noise are frequency, measured in Hertz (Hz), and intensity, measured in decibels (dB).
Human hearing reacts to frequencies between 20 Hz and 20 000 Hz. At low frequencies we hear a bass tone and at high frequencies a high tone. The pitch is therefore the sound frequency that we experience. The tuning fork A, to the right of the middle C on the piano, is 440 Hz. Sound lower than 20 Hz (infrasound) and higher than 20,000 Hz (ultrasound) cannot be heard, but does have an unpleasant and damaging effect.
Sound intensity or volume is measured in decibels (dB) on a logarithmic scale. To take account of the frequency sensitivity of the human ear sound intensity values at the workplace are generally expressed in dB(A), where 0 dB(A) is the hearing threshold. The pain limit is at about 140 dB(A).
A number of typical sound levels are:
- normal talking: 60 dB(A)
- primary school class: 74 dB(A)
- busy road traffic: 85 dB(A)
- pneumatic drill: 100 dB(A)
- jet plane taking off at 100 metres: 130 dB(A)
When is noise dangerous? Four factors determine whether sound is dangerous:
- intensity or strength of the sound (expressed in dB)
- frequency or pitch (expressed in Hz)
- periodicity – how often does the sound occur?
- duration – how long does the sound go on for?
The likelihood of permanent damage to the ear occurs at about 140 dB with one-off exposure. Fortunately this level of exposure seldom occurs at the workplace. Generally damage due to noise occurs after a period of time.
Long-term exposure to noise can result in hearing problems. To protect employees the limit value for daily (8 hours) exposure to sound has been set at 87 dB(A) according to the EU guideline on noise of 2003 which will take effect in all member states in 2006.
´Stop that noise´ was therefore chosen as the theme this year of the European Week for Safety and Health at Work. This Week was initiated by the European Agency for Safety and Health at Work. Information is available on the European Week in all member states at http://osha.europa.eu/en/campaigns/ew2005.
This European Week was organised in the Netherlands by the Focal Point Nederland.
