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ISO 9613.2 Ground Effect    1/1

Strutt|Environmental Noise|ISO9613.2 Ground Attenuation inserts attenuation (dB) into the active row of the worksheet.

Input required is source and receiver heights, source to receiver distance and ground factors.
Ground factors to be used are:
Hard ground: 0
Porous ground: 1
Mixed ground: 0 - 1

The ground effect is calculated by separating the distance between the source and receiver into 3 regions as:


The total ground attenuation for each octave band is calculated as:

`A_(gr) = A_s + A_r + A_m`

Where,
`A_s` is the source region attenuation
`A_r` is the receiver region attenuation
`A_m` is the middle region attenuation

`A_s`, `A_r` and `A_m` are calculated using:

Nominal midband frequency, Hz `A_s or A_r`*, dB A_m, dB
63 `-1.5` `-3q`**
125 `-1.5 + G xx a'(h)` `-3q(1 - G_m)`
250 `-1.5 + G xx b'(h)`
500 `-1.5 + G xx c'(h)`
1000 `-1.5 + G xx d'(h)`
2000 `-1.5(1 - G)`
4000 `-1.5(1 - G)`
8000 `-1.5(1 - G)`


Notes:

`a'(h) = 1.5 + 3.0 xx e^(-0.12(h-5)^2)(1-e^(-d_P//50)) + 5.7 xx e^(-0.09h^2)(1 - e^(-2.8 xx 10^-6 xx d_P^2))`

`b'(h) = 1.5 + 8.6 xx e^(-0.09h^2)(1-e^(-d_P//50))`

`c'(h) = 1.5 + 14.0 xx e^(-0.46h^2)(1-e^(-d_P//50))`

`d'(h) = 1.5 + 5.0 xx e^(-0.9h^2)(1-e^(-d_P//50))`

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* For calculating `A_s`, take `G = G_s` and `h = h_s`. For calculating `A_r`, take `G = G_r` and `h = h_r`. See 7.3.1 (ISO 9613.2) for values of G for various ground surfaces.

** `{:(q = 0 , when \ d_P <= 30 (h_s + h_r)),(q = 1 - (30(h_s + h_r))/d_P, when \ d_P > 30(h_s + h_r) ):}`, where `d_P` is the source-to-receiver distance, in metres, projected onto the ground planes

References:


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