## Noise Dose Terms and Definitions - see also sound exposure

**Noise Dose** is the total sound exposure normalised to an 8-hour working day.

The 8 hour level is also known as the LEP,d : daily personal noise exposure or LEX,8h.

**The Noise Dose Criterion Level** in the UK, is currently 85 dBA and if anyone is exposed to a time-weighted average noise level of 85 dBA during an 8-hour period their *noise dose* is 100%.

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

See also EAV : exposure action value • ELV : exposure limit value

**Noise Dose Meters** record the Pa^{2}·h (pascal-squared hour) levels.

For a given period of time, an increase of 10 dBA in sound pressure level corresponds to a tenfold increase in the *noise dose*.

^{2}·h = 100% Noise Dose = 85 LAeq(8 h) = 85 dBA for 8 hours.

^{2}= 74.9 LAeq,8 h

0.2 Pa

^{2}= 78.0 LAeq,8 h

0.5 Pa

^{2}= 81.9 LAeq,8 h

1 Pa

^{2}= 84.9 LAeq,8 h =

*100% Noise Dose*

2 Pa

^{2}= 88.0 LAeq,8 h

5 Pa

^{2}= 91.9 LAeq,8 h

10 Pa

^{2}= 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

See also projected noise dose • noise dose threshold level**Related Terms - alphabetic listing**

**Estimated Noise Dose**is the exposure received if the measured level had existed for the specified criterion time.

**Noise Damage Risk Criteria**is the recommended maximum noise levels for given exposure periods.

See also exposure action value • exposure limit value

**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 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.

**Noise Dosimeter.**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

**Noise Exposure Time,**the time a person is exposed to noise during a workday - used for calculation of LEP,d (daily personal noise exposure).

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.

See also sound exposure • personal sound exposure meter