Noise Dose Terms, Definitions, Units, Measurements ... see also sound exposure
The Noise Dose Criteria,
in the UK is currently 85dBA and if anyone is exposed to a time weighted average
noise level of 85 dBA during an 8-hour period their noise dose
Employers must assess and identify measures to eliminate or reduce risks from exposure to noise, in order to protect the hearing of their employees.
The British and ISO Standards are based on the 3 dB exchange rate
, which means noise levels of 88 dBA have twice as much energy as levels of 85 dBA. It follows that if 85 dBA = 100% noise dose
, then 88 dBA = 200% noise dose
and therefore the maximum exposure time is restricted to 4 hours per shift - ergo twice the level means half the time
Noise Dose is the total sound exposure normalized to an 8-hour working day.
The 8 hour level is known as the LEP,d (daily personal noise exposure)
EAV (exposure action value) •
ELV (exposure limit value)
The Noise Dose (in physical units) for the whole measurement duration of sound exposure is known as E (Pa2.h)
projected noise dose •
noise dose threshold level
For a given period of time, an increase of 10 dB(A) in sound pressure level corresponds to a tenfold increase in the noise dose.
·h = 100% Noise Dose = 85 LAeq(8 h) = 85 dBA for 8 hours.
0.1 Pa2 = 74.9 LAeq,8 h
0.2 Pa2 = 78.0 LAeq,8 h
0.5 Pa2 = 81.9 LAeq,8 h
1 Pa2 = 84.9 LAeq,8 h = 100% Noise Dose
2 Pa2 = 88.0 LAeq,8 h
5 Pa2 = 91.9 LAeq,8 h
10 Pa2 = 94.8 LAeq,8 h
The Noise Dose examples above assume the UK and EU default criterion time of 8 hours and exchange rate of Q = 3
Related Terms - alphabetic listing
Estimated Noise Dose
is the exposure received if the measured level had existed for the specified criterion time
Noise Dose %
is the noise exposure
expressed as a percentage of the normal allowable daily 'noise dose' collected during measurements on a worker with a noise dosimeter
. Noise Dose %
varies according to National Standards and is sometimes referred to as the % noise dose
Noise Dose Badge,
a small device worn by operator to store fluctuating noise levels during working day, similar to a noise dosimeter
Noise Dose Criterion Level
is the maximum Leq sound level
allowed for an 8-hour period and corresponds to the 100% noise dose value. Also used for calculating the noise dose %
and the ProjDose
Noise Dose Criterion Time
is the time in hours used to calculate noise dose %
, normally 8 hours.
Noise Dose per Hour (DOHR), shows the dose exposure over each hour.
Noise Dose Threshold Level, some regulations specify that for the measurement of noise at work, the noise levels below a certain limit (the threshold) should be disregarded. Some noise dose meters therefore only sum up the contributions from the levels above the threshold and uses these values to calculate the noise dose parameters.
a pocket sized instrument designed to be worn during all or part of the day as a personal noise monitor
in order to check an operator's personal exposure to workplace noise.
Also known as a noise dosemeter and a sound exposure meter
Personal Hearing Protectors
Projected Noise Dose (NProjDose), uses the current noise dose value, logged during the present measurement, and projected forward to give the predicted 8 hour period, assuming the noise levels for the remaining time stays the same.
sound exposure •
personal sound exposure meter