Introduction
Example of noise exposure calculations.
With the results from the measurements it is fairly easy to evaluate the noise exposure at different work locations.
An Example:
- Noise measured at reference point for 3 minutes = 103 dB(A) on average.
- Noise measured at bar on side of venue for 3 minutes = 99 dB(A) on average
- Noise measured in wardrobe in hall of venue for 3 minutes = 90 dB(A) on average
For every increase of 3 dB’s the allowed time is cut in half. This means that if an average of 90 dB(A) is measured at the wardrobe, an employee working here is only allowed to work there for 4 hours. In the same way the employees at the bar, with a measured noise exposure of 99 dB(A), is only allowed to work there for 30 minutes. As concerts usually last for more than 30 minutes, it will be necessary for the employees at the bar to use earplugs.
Selecting the proper earplugs:
Selecting the correct damping factor and type of earplug will be a compromise between economy and required level of quality and carrying comfort. A vast amount of earplugs are available, and it is beyond the scope of this webpage to bring any recommendations. However, in selecting the required damping factor the rule about 3 dB = cut in half applies. Thus if a earplug with a damping factor of 9 dB is selected the staff at the bar may work there for 4 hours, because the reduction of 9 dB = 90 dB which again is 3 dB above 87 dB(A) = 8 hours cut in half = 4 hours.