Conversion formulas for environmental noise metrics
Moderator:Erkki Kuusisto (see all) |
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Scope
What are the appropriate formulas for converting various environmental noise metrics (e.g. LDEN, Lnight, LAeq,22-07, LAeq,07-22, LAeq,24h) into each other?
The formulas should take into account...
- a) the use of different time bases (e.g. 24 h for LAeq,24h, 8 h for Lnight)
- b) the use of penalties/bonuses for different times of day (e.g. 5 and 10 dB for evening and night in LDEN, respectively)
- c) different calculation heights (e.g. 4 m for LDEN, 2 m for LAeq,07-22)
- d) the typical activity profile of the noise source in question (e.g. relative traffic intensities of day, evening, and night).
Definition
Data
A default value for the calculation height effect (i.e. 1.5 dB for the 4m vs 2m difference) has been obtained from several sources (references to be added)
Dependencies
The input data requested by the Converter are:
- beginning and ending periods of day, evening, night
- relative traffic intensities of each of the above periods
- calculation height correction
Note: Default values have been entered into the Converter.
Unit
Not applicable.
Formula
(The conversions include usual dB arithmetics only. Please see the Converter for details.)
Result
The conversion formulas are automatically calculated using the Noise descriptor converter (Excel tool).
- NB! For proper display, use "dot" as the decimal separator in Excel.
See also
Keywords
- noise descriptor
- noise indicator
- noise metric
- conversion factor
References
Related files
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