noise-vibration pre-study
Numerical pre-study on noise-vibration spreading near a power plant
airport
Based on ICAO (International Civil Aviation Organization) standards noise level in airport is calculated using WECPNL (Weighted Equivalent Continuous Perceived Noise Level) as follow
$$\tag{1} {\rm WECPNL} = {\rm dB} (A) + 10 \log N - 27, $$
where ${\rm dB} (A)$ is average noise intensity and $N$ is number of arrival and departures in 24 hours. The average noise intensity is
$$\tag{2} {\rm dB} (A) = 10 \log \left( \frac{1}{n} \sum_{i=1}^n 10^{\frac{L_i}{10}} \right) $$
with ${\rm dB} (A)$ is average noise intensity, $L_i$ is noise value at time of plane $i$ activities, and $n$ is number of aircrafts. One example of the use of Equations (1) and (2) is for the study of Raja Haji Fisabilillah airport, Tanjung Pinang ( Nofriandi et al., 2018 ).
general
There are some average sound levels defined ( NAC, 1977 ), e.g. for yearly day-night is
$$\tag{3} L_{\rm dny} = 10 \log_{10} \left( \frac{1}{365} \sum_{i=1}^{365} 10^{L_{{\rm dn},i} / 10} \right), $$
where $_{{\rm dn},i}$ is the day-night average sound level for the $i$-th day out of one year.
calculation
After manual measurement, e.g. LZeq or Leq dB(Z) by the optimus sound level meter, then add the A-weighting corrections to the measured levels ( NN, 2020 ). Various weightings have their owns meaning ( E, 2021 ) and formula ( W, 2024a ; W, 2024b ).