EN510-en-GB_V1.0 8/17
6
Air Flow (CFM, CMM) Volume Measurements
•
Press and hold the
M
button until ‘AirFl’ appears.
•
Enter the duct area (in square feet or meters) by short pressing
M
and long pressing
R
until
‘m-2’ (m
2
) or ‘f-2’ (ft
2
) appears. Short press the power button to increase or
H
to decrease
the area; Long press the power or
H
button to scroll quickly. See area equations below.
•
Short press to save.
•
Remember to convert inches, centimeters, or other unit to square feet or square meters
before entering the area; otherwise, the air flow readings will not be correct.
•
Place the vane in the air duct and read the air flow reading in CFM (ft
3
) or CMM (m
3
) units on
the LCD.
Area equation for rectangular or square ducts
Area equation for circular ducts
Cubic equations
CFM (ft
3
/min) = Air Velocity (ft/min) x Area (ft
2
)
CMM (m
3
/min) = Air Velocity (m/s) x Area (m
2
) x 60
Width (W)
Height (H)
Area (A) = Width (W) x Height (H)
Radius (r)
Area (A)
=
π
x
r
2
Where
π
=
3.14
and r
2
=
radius x radius
