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Strutt|Building Acoustics|Noise Breakout from Room calculates in the active row the sound power radiated from a plantroom, given the common surface area S of the plantroom and receiving room and the transmision loss TL of the partition.

Strutt calculates the noise breakout using the following formula:

`L_(W,rad) = L_(p,rev) + TL + 10log_10(S) + Cd`

Where:
`Cd` is -6 dB

The above formula assumes a perfectly diffuse field. The user also has the option of modifying the above formula to utilise the diffusivity terms given in EN 12354-4:2000 Annex B as follows:

• `Cd` is -6 dB for relatively small, uniformly shaped rooms (diffuse field); in front of reflecting surface
• `Cd` is -3 dB for relatively small, uniformly shaped rooms (diffuse field); in front of absorbing surface
• `Cd` is -5 dB for large flat or long halls, many sources (average industrial building); in front of reflecting surface
• `Cd` is -3 dB for industrial building, few dominating directional sources; in front of reflecting surface
• `Cd` is 0 dB for industrial building, few dominating directional sources; in front of absorbing surface

References:

• Bies and Hansen (2nd Edition) p 208 - 209
• EN 12354-4:2000 Annex B