340
Heating-Ventilating-Cooling: Design Criteria
For instance, a 10,000 square foot service module with a 2.4 c.f.m.
maximum design load would require two eight square foot supply branch
ducts, two shear wall openings 4' x 3' and two openings for general
exhaust and special exhaust of 5' x 3'. The mechanical room would be
sized for the maximum 24,000 c.f.m. unit. These sizes would become
standard for all service modules throughout the hospital.
344.3
VARIABLE CHARACTERISTICS
In addition to the range of load demands in c.f.m. to the various
departments in the hospital, the subsystem must be capable of satisfying
various space design conditions.
A typical range would be:
CHARACTERISTIC
MINIMUM
MAXIMUM
Design temperature
70 degrees F.
80 degrees F.
Relative humidity
30 percent
60 percent
Filtration
35 percent
95 percent
Air motion
10 f.p.m.
35 f.p.m.
Recirculation
0 percent
75 percent
Also special areas may require particular modification for odor control, and
other areas may need pressure differentials between adjacent spaces, or
adaptation of the system to use disinfectant devices for critical asepsis
control.
As each service module will be primarily served by one fan unit and
recirculation system, the module's performance characteristics would have
to be set at the highest value required for its particular functional zone.
This would suggest that in the range of possible service module sizes of
10 to 15,000 square feet, it would be preferable to take the lower value as
optimum, to reduce the area affected by expensive requirements. In
principle, all the permanent components of the HVC subsystem should be
designed and laid out to potentially handle the worst case characteristics
comfortably.
1 - 200
Previous Page
