Dwyer FLST User Manual
Page 2
Oval Stations
Standard oval airflow measuring stations include a 18 gage galvanized
casing, 5 inches long between beads with 1-1/4 inch connecting sleeve
on each end (7-1/2 inch overall length). Actual O.D. dimensions are 1/4
inch less than specified duct I.D. dimensions.
INSTALLATION
The elements may be installed in any duct configuration. However, the
accuracy of the installation is dependent on the flow conditions in the
duct. The minimum installation requirements for the elements based upon
a uniform velocity profile approaching the duct disturbance for flow rates
less than 2,500 fpm are shown below. Add one duct diameter to the
installation requirements shown below for each additional flow rate of
1000 fpm. These are not ideal locations. It is always best to locate the ele-
ments as far as possible from all duct disturbances, with upstream distur-
bances being the most critical consideration.
Station
Size
6˝ - 15˝
16˝ - 44˝
45˝ - 72˝
73˝ & Over
Flange
Thickness
0.064˝
0.064˝
0.188˝
0.188˝
Flange
Size
1˝
1-1/2˝
1-1/2˝
2˝
Casing
Length “L”
6˝
6˝
10˝
12˝
Circular Flange Dimensions
Station Size
8˝ - 72˝
73˝ & Over
Flange Size
1-1/2˝
2˝
Rectangular Flange Dimensions
Oval Flange Dimensions (Optional)
Station
Size
Up to 48˝
Over 48˝
Flange
Thickness
0.064˝
0.188˝
Flange
Size
1-1/2˝
1-1/2˝
Casing
Length “L”
6˝
8˝
Circular Stations
Standard circular airflow measuring stations include a 16 gage galvanized
casing with attached 90° connecting flanges as listed above.
Rectangular Stations
Standard rectangular airflow measuring stations include a 16 gage galva-
nized casing, 5 inches long, with formed integral 90° connecting flanges
as listed above.
Notes:
Round Ducts:
D = Duct diameter
Rectangular Ducts:
D = 4HW
H = Duct height
W = Duct width
ELBOWS
TRANSITIONS
π
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