1.8.2.4 Outside air intake shall not be near hot exhaust discharging
horizontally or deflected down, nor be near plumbing vents, animal room
exhausts, generator exhausts, loading docks, automobile entrances,
driveways, passenger drop-offs, cooling towers, incinerator and boiler
stacks.
1.8.2.5 Louvers shall be designed for a maximum velocity of 3.8 m/s
(750 fpm) through the free area of 35 percent. Drainable louvers may be
designed for a maximum velocity of 5.0 m/s (1000 fpm) and 45 percent
free area.
1.8.3 SPECIAL REQUIREMENTS
Separating air intakes and exhaust air outlets by 10 m (30 ft) as
recommended by codes is a minimum requirement under ideal conditions.
Other factors such as wind direction, wind velocity, stack effect,
system sizes, and height of building must be evaluated and location of
intakes and outlets shall be adjusted as required. Refer to Chapter
"Air Flow Around Buildings" of ASHRAE Fundamentals Handbook for
analyzing these factors.
1.8.4 TYPE OF LOUVERS
1.8.4.1 The type of louvers depends upon the application and should be
coordinated with architectural drawings and specifications. The desired
performance characteristics for each type of louver should be listed in
Section 10200, LOUVERS AND WALL VENTS.
1.8.4.2 Flat blade (non-drainable) louvers are recommended for most
applications.
1.8.4.3 Drainable louvers should be considered for applications where
available area is restrictive. Example: Emergency Generators. Drainable
louvers are also recommended for situations where the air handling unit
pre-filters are in close proximity of the outside air intake.
1.8.4.4 The use of the drainable louvers is discouraged for areas where
dirt and debris may clog drain gutters.
1.9
ENERGY CONSERVATION
1.9.1 GENERAL
The HVAC systems design shall be designed to conform to the mandatory
energy conservation guidelines outlined in Article 1, Paragraph 1.1.7.
1.9.2 BUILDING THERMAL ENVELOPE
1.9.2.1 NEW CONSTRUCTION: The building thermal envelope for the new VA
health care facilities shall be energy efficient to minimize the heat
gain and loss due to conduction and solar radiation. The building
envelope shall minimize the air leakage to and from the occupied spaces
and shall also ensure condensation control.
(a) Recommended "U" Values: The following represents the recommended
"U" values of walls, roof and glass, and the Shading Coefficients (SCs)
of glass for new construction. These values should be used to meet the
overall Uo factor, for the building gross wall area, defined under the
next paragraph.
HVAC DESIGN MANUAL
1-26
GENERAL REQUIREMENTS
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