*5.3.2 Thick barrier approach*

The verification for this case study (*t* = 61 m) is presented in **Table 14**.

#### *Management of Noise Pollution*


**Table 13.**

*IL according to Kurze-Anderson and expected sound pressure levels at P1 (all values are in dB).*


**Table 14.**

*Verification of thick/thin barrier criteria (all values are in m).*

Based on these results, the green barrier could be considered a thick barrier for all the frequencies. Eq. (3) can be used for solid barriers either thin or thick. Since it is not developed for tree or green barriers, overestimation of IL is expected.

The IL calculated using Eq. (3) without subtracting Agr and the SPL expected at the receiver are presented in **Table 15**. Since the distance between the source and P1 is greater than 300 m, K = 1. Agr has just been considered by the general attenuation terms; it must not be subtracted twice.

Note that the IL for the band of 63 Hz has been considered because the wavelength at this frequency is significantly shorter than the barrier width *t*.

The calculated SPL at 4000 Hz and 8000 Hz were lower than the background noise at P1; thus, they have been replaced by the background values in **Table 2** (figures in green in **Table 15**).
