Averaging level

The average level is a measurement and calculation parameter in acoustics and is used to identify noise situations that fluctuate over time; it is also referred to as the emission level. This level is used for noise events that are composed of constantly changing partial noises of different volume . This applies, for example, to road traffic noise or noise in the workplace.

The averaging level reflects the sound level that corresponds to the sound energy averaged over a certain period of time. This is also the so-called energy - equivalent continuous sound level .
If the averaging level is known at a specified immission location, the assessment level results from this averaging level and adding up assessing surcharges, e.g. B. as a nuisance surcharge or according to tonality.

If several averaging levels are added in terms of sound energy , the total level (including the resulting level) is obtained.

calculation

The following formula can be used to calculate the mean of a level over a certain assessment period or for a certain number of levels:

{\ displaystyle L_ {m} = 10 \ cdot \ lg \ left ({\ frac {1} {T}} \ cdot \ int \ limits _ {0} ^ {T} 10 ^ {0.1 \ cdot L ( t)} dt \ right) \ quad {\ mbox {or}} \ quad L_ {m} = 10 \ cdot \ lg \ left ({\ frac {1} {N}} \ cdot \ sum \ limits _ {i = 1} ^ {N} 10 ^ {0.1 \ cdot L_ {i}} \ right)}

L _m	Averaging level
T	considered time interval (assessment period)
L (t)	Sound level as a function of time t
N	Number of measured sound levels (with 1 i N ) ${\ displaystyle L_ {i}}$ ${\ displaystyle \ leq}$ ${\ displaystyle \ leq}$

Norms and standards

DIN 45641 - averaging of sound levels