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noise-vibration pre-study

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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

WECPNL=dB(A)+10logN27,(1)\tag{1} {\rm WECPNL} = {\rm dB} (A) + 10 \log N - 27,

where dB(A){\rm dB} (A) is average noise intensity and NN is number of arrival and departures in 24 hours. The average noise intensity is

dB(A)=10log(1ni=1n10Li10)(2)\tag{2} {\rm dB} (A) = 10 \log \left( \frac{1}{n} \sum_{i=1}^n 10^{\frac{L_i}{10}} \right)

with dB(A){\rm dB} (A) is average noise intensity, LiL_i is noise value at time of plane ii activities, and nn 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

Ldny=10log10(1365i=136510Ldn,i/10),(3)\tag{3} L_{\rm dny} = 10 \log_{10} \left( \frac{1}{365} \sum_{i=1}^{365} 10^{L_{{\rm dn},i} / 10} \right),

where dn,i_{{\rm dn},i} is the day-night average sound level for the ii-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).

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