A properly dimensioned ventilation system is crucial for optimal broiler performance. One of the essential parts of the ventilation system is the ventilators. There are many different ventilators available, with all of them having their own specific dimensions. Sometimes the dimensions (e.g. air amount at a certain negative pressure) are not completely identical with what the manufacturer puts in its label.

At BESS Laboratory at the University of Illinois, a high number of ventilators used in agriculture and industry are checked for their performance. The results are published on the following web site: www.bess.uiuc.edu

When we want to check a given ventilator in the field ourselves, we can use the so-called 9-point measurement. This is done by putting an imaginary cross over the ventilator (with all shutters and other accessories intact) and measure the air velocity in the centre, half way on each arm of the cross, and at the end of each arm of the cross (at the tip of the ventilator). This then gives 9 separate readings. Get average of the 9 readings to arrive at an average air velocity (m/s).

Calculate the surface (m2) of the ventilator with the following formula:
surface is: (1/2 d x 1/2 d) x 3.14 where d is the diameter of the ventilator (in meters)

for example, the average air velocity is 10 m/s
the diameter of the ventilator is 0.7 m

(0.35 x 0.35) x 3.14 = 0.38465 m2 x 10 m/s = 3.8465 m3/s