Dectron, Inc. March 2012
DSH/DSV/RSH/DBH/RBH Series Dehumidifier Owner’s Manual
T.A.B. Locate Airflow Measurement Points
Data subject to change without notice.
194
DECTRON
This is not a convenience air conditioner - it is a process dehumidifier. Proper airflow is essential.
Supply-air flow should be calculated from a duct traverse, per ANSI/ASHRAE 111-2008 or other applicable
procedure.
Locate sections of the supply duct, the outdoor-air intake duct
(if any), and the exhaust-air duct (if any) for airflow measurement.
The traversing plane for airflow measurement should be accessible
and
1. full-sized, unbranched, and straight for at least
three effective
duct diameters upstream of the traversing plane, or per
ASHRAE 111-2008, whichever is greater, and
2. full-sized, unbranched, and straight for at least
one effective
duct diameter downstream of the traversing plane, or per
ASHRAE 111-2008, whichever is greater.
For this purpose, the effective duct diameter E
L
is given by
E
L
= 4ab / π
duct-traversing
plane
Outdoor-air-intake flow and exhaust-air flow should be calculated from a duct traverse, where ducts are available.
Some outdoor units may have side hoods instead of ducts. In this case, measure air speed at several points
across the bird screen, using a rotating-vane anemometer per ANSI/ASHRAE 111-2008 or other applicable
procedure. The cross-sectional area will be dimension a times dimension b.
If reliable side-hood exhaust-air speeds cannot be determined, adequate results can be obtained by adjusting the
exhaust-air flow rate to produce a slight negative pressure between the natatorium
and the outdoors, and between the natatorium and adjacent spaces of the building
except
any chemical-storage area.
NOTE: If the chemical-storage area is inside the building, it should be constantly
maintained at the lowest pressure in the building.
Outdoor-air-intake flow and exhaust-air flow should be calculated from a duct traverse, where ducts are available.
Some outdoor units have top hoods for outdoor-air intake. In this case, measure air speed at several points
across the bird screen, using a rotating-vane anemometer per ANSI/ASHRAE 111-2008 or other applicable
procedure. The cross-sectional area will be twice the dimension a times dimension b.
Locate airflow measurement planes.
T.A.B.
To Next Page
Loading...
Need help?
General
