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Directivity Correction for Internal Outlets
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Strutt|Directivity|Internal Outlet Directivity inserts directivity corrections into the active row of the worksheet.
The following outlet positions have been included in the function:
- Centre of ceiling - more than 1 m away from any other major room surface, sound deemed to spread through solid angle of 180º
- Against one wall - closer than 1 m to one other major room surface, sound deemed to spread through solid angle of 90º
- In a corner - closer than 1 m to two other major room surfaces, sound deemed to spread through solid angle of 45º
- Free space - more than 1 m away from any major room surface, sound deemed to spread through solid angle of 360º
Data for these positions are an amalgamation of the values found in Woods Practical Guide to Noise Control and SRL Noise Control in Building Services (see references below). Note that the SRL method is also implemented in Strutt under Louvre Directivity.
These directivity values are the cumulative directivity due to the outlet and its location in the room, rather than of the outlet itself. The additional condition of free space has been calculated with a correction of -3 added to the centre of ceiling values.
References:
- Woods Practical Guide to Noise Control, Sixth Impression 1990, Figure 5.11 pg. 96
- Sound Research Laboratories, Noise Control in Building Services, First edition 1988, Figure 11.2 pg. 340
- [internal Arup reference only]Arup Blue Book, Sound and Vibration in Mechanical Services Design, p51
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