Assumptions for sound calculations

Fulfilment of sound requirements

Installation requirements

EXHAUSTO air handling units must be fitted with silencers in the duct system in accordance with the applicable sound regulations for both the premises to be ventilated and the surrounding areas.

To meet current standards the duct system should be insulated for sound, thermal loss and condensation.

Sound calculations

Sound output levels are used as the basis for calculating the sound pressure level in the operating area of the unit, and the level of silencing required in the duct system itself.

 Element  Description  Note
 KW Correction factor for calculating sound output in the octave band    
 KWA Correction factor for calculating A-weighted sound output Not applicable to VEX300
 KpA Correction value for calculating A-weighted sound pressure Not applicable to VEX300C. For calculation of sound pressure level for areas surrounding VEX300C, contact EXHAUSTO
 LW Sound output level dB Reference 1 pW
Tolerance ± 3dB
 I upper operating range  
 II medium operating range  
 III lower operating range (Certain cases only - see curve)

Sound output level to duct (outdoor air/extract air)
Measured in accordance with ISO 5136

LW1 = LWA1 + KW

LWA1 to be read off

Sound output level to duct (supply/extraction air)
Measured in accordance with ISO 5136

LW2 = LWA2 + KW

LWA2 to be read off

Sound pressure level for surrounding area
VEX300C and VEX308 measured in accordance with ISO9614
All other VEX measured in accordance with ISO3744

LW3 = LWA3 + KW

LWA3 to be read off

Sound pressure level dB (A) at one metre distance from edge of VEX with hemispherical sound propagation in free field and with insulated connection ducts.

For VEX100 and VEX200:

LpA3 = LWA1 + KpA

LWA1 to be read off


LpA3 = LWA3 + KpA

LWA3 to be read off 

 See measurement setup

Calculation programs

Use EXHAUSTO's free calculation programs for calculating ventilation plant and system solutions

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Vex overview

VEX Summary

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