EZ30 Datasheet, PDF (5/6 Pages) Extech Instruments Corporation. – EzFlex Thermo-Anemometer

Useful Equations and Conversions
Volume Measurements
To determine CFM (cubic feet per minute) or CMM (cubic meters per minute) in a duct, the
area of the duct must first be measured (use the equations below). Then multiply an air
velocity measurement by the area measurement to obtain CFM or CMM.
Area equation for rectangular or square ducts
Height (H)
Width (W)
Area (A) = Width (W) x Height (H)
Area equation for circular ducts
Radius
Area (A) = x r²
Where = 3.14 and r² = radius x radius
Cubic equations
CFM (ft³/min) = Air Velocity (ft/min) x Area (ft²)
CMM (m³/min) = Air Velocity (m/sec) x Area (m²) x 60
NOTE: Measurements made in inches
must be converted to feet or meters before using the above formulae.
Unit of Measure Conversion Table
1 m/s
1 ft/min
1 knot
1 km/h
1 MPH
m/s
1
0.00508
0.5144
0.2778
0.4464
ft/min
196.87
1
101.27
54.69
87.89
knots
1.944
0.00987
1
0.54
0.8679
5
km/h
3.6
0.01829
1.8519
1
1.6071
MPH
2.24
0.01138
1.1523
0.6222
1
Model EZ30 Version 1.1 04/06