Project Name
Project Number
UEPH Complex
Statement of Work
26 November 2001
10-3
HUMID AREA DESIGN. [Climates which have 3000 hours or more of 19.4 degrees
C [67 degrees F] or higher wet bulb temperature in combination with an outside design
condition of 50 percent or higher relative humidity, or climates which have 1500 hours or more
of 22.8 degrees C [73 degrees F] or higher wet bulb temperature in combination with an outside
design condition of 50 percent or higher relative humidity shall be considered humid areas. In
other areas that do not meet the strict definitions of a humid area but experience humid
conditions on numerous occasions, these same criteria shall be used by the designer as
appropriate for the facility and the climate.] In humid areas, all air heating and cooling systems
shall be provided, and economizer cycles will not be allowed. Closet and storage spaces shall
have louvered doors, and building return air shall be drawn through these spaces to a ducted
return air system. Cooling coils shall have a maximum of 315 fins/m [8 fins/inch] to allow for
easy cleaning, and shall be sized for a maximum face velocity of 2.8 m/s [550 fps] to preclude
moisture carryover. Heating and cooling equipment in humid areas shall be designed to meet
the load determined by computer calculation. However, a larger fan may be required to meet
minimum air flow requirements than would be anticipated based on the computer load.
Equipment may be oversized by no more than 15 percent of the computer generated sensible
load.
10-3.1
Load calculations. The one percent wet bulb temperature, from the approved
weather data source of 10-1.2 above, will be used in calculating the latent cooling load and for
equipment sizing. In addition to calculating the cooling load at maximum design temperature,
cooling load calculations or thermal simulations should also be made at maximum dew point
temperatures or for low temperature, high humidity conditions to determine the greatest
dehumidification load that may be encountered. Latent heat gain due to water vapor flow
through roofs and walls will be included in the cooling load analysis when the ambient design
dew point exceeds the room design dew point by more than 11.1 degrees C [20 degrees F].
10-3.2
Chilled water systems. The cooling capacity of 350 kW [100 tons] and over systems
will be divided between two or more chillers to ensure reliability and constant chilled water
supply without temperature fluctuations, to prevent short cycling, and to minimize hot gas
by-pass. The combined capacity of the chillers will not exceed the total requirement, including
diversity. The selection of the number of chillers will be based on the analysis of part load
operating hours for extended periods of low load conditions.
10-3.3
Packaged units. Packaged unitary units with multiple reciprocating compressors (not
to exceed eight) will be used for systems between 123 kW and 750 kW [35 tons to 200 tons].
Each compressor will have separate, independent, refrigerant circuits and cycles to provide
multiple steps of capacity control. Two compressors may be combined into one independent
refrigerant circuit. For systems up to 123 kW (35 tons), single compressors with a minimum of
three-step capacity unloading may be used.
10-3.4
Outside air. Where the outside air requirements are a significant part of the cooling
load, the use of desiccant cooling, enthalpy wheels and similar devices for conditioning the
outside air and transferring latent and sensible heat to the exhaust air shall be considered. If
appropriately sized, these units can eliminate or minimize the latent load in the conditioned
space saving significant energy and greatly increasing the comfort level.
10-4
MECHANICAL SYSTEMS. Each building shall be provided with a [central] heating
[and air conditioning] system[s]. Systems shall be designed, installed, balanced, and adjusted
to distribute heat [and cooling] to all habitable rooms, as well as bathrooms, in proportion to the
calculated load requirements of these spaces. [The Installation shall determine the allowable
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