15 May 2003
2-15.4 Ventilation. Condition outdoor air at all times through a continually operating
air-conditioning system. Consider using a separate system for outdoor air where
necessary to maintain a sensible heat ratio of the mixed air entering the primary air-
conditioning unit within the required limits of commercially available equipment and/or to
reduce corrosive, salt-laden air from entering the primary air distribution system.
Ensure that the building is maintained under a slightly positive pressure to minimize
infiltration to the greatest extent possible.
2-15.5 Air and Water Temperatures. Base the supply air temperature and quantity,
and chilled water temperature on the sensible heat factor, coil bypass factor, apparatus
dew point, and outdoor humidity ratio.
2-15.6 Outdoor Design Temperatures. Use the one percent wet bulb temperature in
cooling calculations and equipment selections.
2-15.7 Closets And Storage In Air Conditioned Facilities. These areas should be
either directly air conditioned or provided with exhausts to transfer conditioned air from
2-15.8 Reheat. Where reheat is required to maintain indoor relative humidity below 60
percent, consider heat recovery, such as reclamation of condenser heat, in life cycle
2-15.9 Economizer. Economizer cycles generally will not be used due to the high
moisture content of outside air.
2-15.10 Penetrations Of Conditioned Envelope And Thermal Bridging.
Considerable moisture often enters the conditioned envelope both through penetrations
at locations such as door and window frames and intersections of walls or walls and
roofs. Provide details on the drawings for penetrations and potential thermal bridges.
. The local water composition
design of water treatment for mechanical systems. A water analysis may be available
from the using agency. If an analysis is unavailable, obtain a sample of the raw water.
Test the sample and include the results in the applicable contract specifications. Design
water treatment systems for boilers in accordance with UFC 3-430-02FA Central Steam
Boiler Plants, or UFC 3-430-04FA High Temperature Water Heating Systems, for Army
and Air Force. Provide water treatment systems for cooling towers for prevention of
corrosion, scale, and biological formations. In most cases, a water treatment system is
required for closed chilled-water systems, hot water systems, or dual-temperature
MECHANICAL VENTILATION FOR INDUSTRIAL APPLICATIONS. For
applications not covered by ASHRAE criteria, use the ACGIH Industrial Ventilation, A
Manual of Recommended Practice.