Calculation of noise exposure

The relevant evaluation parameter for noise exposure is the individual level of noise exposure. The noise exposure is the A-weighted energy equivalent sound pressure level over an appraisal period of 8 hours (a whole working day). If the individual exposition varies considerably there can also be considering a 40 hours working week.

If the individual noise exposure level exceeds 85 dB (A) hearing impairment could be the consequence and measures have to be taken. So for the calculation of the individual level of noise exposure two indicators to be measured are necessary:

• the A-weighted energy equivalent sound pressure level (in dB)
• the individual exposure time per day (in minutes)

If the exposure time is not the whole working day but e.g. half a day, the relevant noise exposure level is less, so there has to be made some calculation work. Note: The relevant value for the individual worker is the noise exposure level!

Examples:

The whole thing gets even more complicated if different sound pressure levels and exposure times have to be added, by doing it with a calculator quite an ambitious task. Example: 2 hours at 90 dB and 4 hours at 85 dB and two more hours at 84 dB on a working day result in an individual level of noise exposure of 87 dB.

The following exposure level calculator does this task of calculating the individual level of noise exposure quite easily: Just fill in the name of the respective worker and subsequently

• the activity/machine (first row)
• the measured sound pressure level in dB (second row)
• the exposure time (third row)

This you do for every activity or machine workplace for a given worker, so if there are four different sound pressure levels with three respective exposure times you have to fill in four lines. Then you press “calculate” – and get the individual level of noise exposure for the given worker.