Useful Equations And Conversions - Extech Instruments AN200 User Manual

Useful Equations and Conversions

Area equation for rectangular or square ducts
Width (W)
Area equation for circular ducts
Radius
Cubic equations
CFM (ft
CMM (m
must be converted to feet or meters before using the above formulae.
Unit of Measure Conversion Table
m/s
1 m/s 1
1 ft/min 0.00508
1 knot 0.5144
1 km/h 0.2778
1 MPH 0.4464
Height (H)
Area (A) = Width (W) x Height (H)
Area (A) =
Where
3 /min) = Air Velocity (ft/min) x Area (ft
3
/min) = Air Velocity (m/sec) x Area (m
NOTE: Measurements made in inches
ft/min knots
196.87
1 0.00987
101.27
54.69
87.89 0.8679
13
x r 2
= 3.14 and r 2 = radius x radius
2
) x 60
km/h
1.944 3.6
0.01829
1 1.8519
0.54 1
1.6071
2 )
MPH
2.24
0.01138
1.1523
0.6222
1
AN200 V2.1 05/07