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).