Measuring The Exhaust Airflow - Spring Air Systems DN REV-LOW Maintenance And Operating Manual

REMOVEABLE INSERT INSTALLATION
CORRECT

MEASURING THE EXHAUST AIRFLOW

The exhaust air is measured along the inlet slot of the ventilator. To ensure accurate results take a reading every foot
along the length of the ventilator is recommended.
VANAXIAL VELOMETER
Measuring Exhaust Air
Figure 8
Calculating the Exhaust Air
Calculate the average velocity across the inlet slot and refer to the chart below for the
corresponding CFM/ft (l/s/m).
Ventilator Type
DN-B-F/DN-DI
DN-B-F/DN-DI
DN-B-F/DN-DI
DN-B-F/DN-DI
DN-B-F/DN-DI
DN-B-F/DN-DI
DN-B-F/DN-DI
DN-B-F/DN-DI
DN-B-F/DN-DI
DN-B-F/DN-DI
HANDLE IS UP AND OUT
UP SIDE DOWN
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.
Velocity
Fpm
450
675
900
1125
1350
1575
1800
2000
2250
2450
Chart 1
DN-Rev-LOW Maintenance and Operating
PITOT TUBE OR ANEMOMETER
Measuring Exhaust Air
Figure 9
Exhaust Air Volume
m/s CFM/ft
2.3 100
3.4 150
4.6 200
5.7 250
6.9 300
8.0 350
9.2 400
10.2 450
11.5 500
12.5 550
Manual
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.
l/s/m
140
210
275
340
410
480
550
620
690
755
7