MIL-HDBK-1003/3
Table 7
Major Types of HVAC Fans
Type
HVAC Application
Centrifugal with backward
Large HVAC systems where fan
inclined airfoil blades
energy efficiency becomes
significant
Backward inclined centrifugal General HVAC
Forward inclined centrifugal
Low pressure HVAC, mainly in
furnaces and package equipment
Vane axial
General HVAC where compact size
and straight flow is wanted
Equipment room ventilation and
general ventilation for comfort
cooling
(7)
Fan entrance (including vortex dampers),
(8) Fan discharge (based on discharge
configuration), and
(9) Velocity pressure loss (if fan outlet velocity
is lower than duct velocity).
b) Pressure Drop of Duct Systems.
Pressure drop
calculations of duct systems shall include:
(1)
Straight unlined or lined ductwork,
(2)
Static pressure regain or loss due to
transitions,
(3)
Fittings,
(4)
Branch takeoffs,
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