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Spring Air Systems Water Wash Ventilator Maintenance Manual 11/01
30
Measuring the Exhaust Air
The exhaust air is measured along the inlet slot of the ventilator. To ensure accurate results take a reading every one-
foot along the length of the ventilator is recommended.
VANAXIAL VELOMETER
Hold the instrument perpendicular to the VORTEX BAFFLE and parallel to the throat
(inlet slot) of the ventilator. Velometer should not exceed three inches in diameter.
Measuring Exhaust Air
Figure 38
PITOT TUBE OR ANEMOMETER
Hold the instrument perpendicular to the VORTEX BAFFLE and parallel to the throat (inlet
slot) of the ventilator. Take three readings across the throat and average the results.
Measuring Exhaust Air
Figure 39
Calculate the average velocity across the inlet slot and refer to the chart below for the corresponding CFM/ft (l/s/m).
Velocity
Exhaust Air Volume
fpm m/s
CFM/ft
l/s/m
450 2.3 100 300
675 3.5 150 300
900 4.6 200 300
1125 5.7 250 350
1350 7.0 300 400
1575 8.0 350 500
1800 9.0 400 550
2000 10.0 450 550
