Conditions for capacity data

BESB and BESF box ventilators are measured 1 metre away from either side of the ventilator duct.

A system pressure drop can occur if the minimum distance is not maintained during installation and this should be taken into consideration during project engineering.

The size of this system pressure drop can be calculated using the research literature.


pt is the total available pressure.

The stated operating curves show the characteristics of the fan with downwards regulation.

The SFP curves show the specific electricity used in J/m3 ventilated air volume through the fan..

Measurement set-up





pt = total pressure

pt = pt1,2 - pt1,1

Temperature = 20°C

Density = 1.2 kg/m3

SFP Specific power consumption for air transport (J/m3)

qv = volume flow (l/s)

P1 = absorbed power (Watt)

P1 = SFP x qv x 10-3 = SFP (J/m3) x qv (l/s):1000
( 1000 l/s = 1 m3/s)













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