*Evaluation of Industrial Noise Reduction Achieved with a Green Barrier: Case Study DOI: http://dx.doi.org/10.5772/intechopen.108835*

ones. Since this sound attenuation could be intended as due to the presence of the tree barrier, it confirms the hypothesis that green barriers can behave as acoustic ones.

Four options were tried for calculating the sound attenuation provided by the green barrier. Kurze-Anderson and the thick barrier approach gave a good prediction of SPL at the receiver, both in octave bands and for A-weighted values, especially for frequencies between 1000 Hz and 4000 Hz, where the results without considering the tree barrier attenuation were the least accurate. Adding the lateral diffraction did not improve the calculated results in this case.

The best approach for calculating the green barrier *IL* was the thick barrier approach and the second in accuracy was Kurze-Anderson.

The approach of ISO 9613:2 was the least accurate, worse than Hoover's approach.

It is possible that the long distance between the source and the receiver—and also the long distance between the source and the green barrier, makes the barrier behave as if it was a solid obstacle, while the leaves and canopy effects become negligible.

This finding opens the possibility of successfully using the IL prediction equations for solid acoustic barriers (both thin and thick) to estimate the acoustic performance of green barriers, at least under conditions similar to those of this case study. Further research should be needed to recommend wider use, e.g., for distances further than a given one.
