In my recent research, i have found many formulas that allow us calculate the noise indicator L10 (defined as the the noise level that exceeded 10% of the time of measurement, basically related to road traffic noise). Starting from the paper of Delany in 1976, who related L10 primarily with the hourly traffic flow (q), speed (v), and % of heavy vehicles (p) by the following formula :
L10 = 10 log q + 33 log (v + 40 + 500/v) + l0 log (1 + 5p/v) - 27.6 ... (1)
In 1978, Marion Burgess found a that there's a relationship between L10 and Leq following a linear regression by this equation : Leq = L10 - 3 dB ... (2)
After that, in 1988 the Department of transport, Welsh office published the guide of CRTN (Calculation of Road Traffic Noise), in page 39, we find a chart that simplifies the work by only predicting the hourly L10 in terms of traffic flow, speed and % of HV, which also provided another formula : L10 = 42,2 + 10 log q ... (3)
In 2006, a book named Architectural Acoustics written by Marshal Long, in page 135 a relationship between Leq and L10 also provided by the following equation :
Leq = L10 - 1,28ꭤ + 0.115ꭤ² ... (4)
where ꭤ is the standard deviation of the highway noise level, generally it is between 2 & 5 dB (3,2 dB is the best value).
And if it happens and i used NOISE CAPTURE calibrated application on my Oppo Realme 5 smartphone the difference between the results in equation 2 and 4 is slightly notable ( ±0,08 dB).
Keep in mind that the purpose to know these informations is to perform road traffic noise measurements correctly under an Algerian city conditions.
Hi Ali,
Why dont you calculate the L10 directly from the measurements? I mean, if you have the logger of each measurement (the logger is each individual value reported by the sound level meter according to the integration time) you can compute the L10 very easily (Leq as well). Then, you can compare this value with formulas 2 and 4 to see which correlates better.
I think that to have quantitative information is the best way to make this analysis.
Regards,
Diego
Hi Diego Mauricio Murillo Gomez
Unfortunately, the sound level meter that i use is not that sophisticated, it only shows the SPL and then with a help of the software NOISE LOGGER COMMUNICATION TOOL i calculate Leq.
i'd like to know when to use these formulas.
Can you send me a sample of the file generated by the NOISE LOGGER COMMUNICATION TOOL? I coud try to see if it is possible to calculate L10.
the following video demonstrates both sound level meter and the software i am using.
i will send you a sample of the file, but first you have to download and install the software.
For accurate and reliable correct results, field noise measurements should be used. Calculations can be easily calculated L10 using statistical analysis
It Can only be done with special meter What ever it may L10,L50,L90, Leq
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