(d) HVAC equipment serving BMT areas shall be on emergency power.
(e) AIR HANDLING UNIT SELECTION: Provide a dedicated air handling unit and
exhaust system to serve the Bone Marrow Unit comprising of the patient
rooms, donor rooms, recovery room, nurse's station, conference room and
other associated areas, such as circulation, lounge, toilets, etc. The
unit shall run 24 hours a day.
(f) TEMPERATURE CONTROL: For all special areas, including patient rooms,
recovery rooms, donor rooms and medical preparation rooms, the supply air
quantity shall be allowed to remain constant and the space temperature
shall be maintained by controlling the reheat coils at the air terminal
units and the perimeter heat, if provided. For the remaining areas, the
variable air volume terminals with or without reheat coils may be used.
The need for a volumetric control for the supply air fan should be
determined on the basis of the air balance calculations.
3.6.2 SPECIAL CONSIDERATIONS
It is essential to maintain an environment with minimum airborne fungal
pathogens in the patient and recovery rooms. These spaces shall be sealed
by the anterooms. To accomplish this task, the following special features
should be incorporated in the HVAC system design.
(a) AIR FILTERS: For each patient and recovery room, supply air duct-
mounted HEPA filters with 99.97 percent efficiency and @ 0.3 micron
particle shall be provided to arrest any opportunistic fungal which may
have been dislodged from the air handling unit due to interruption of air
flow during scheduled maintenance. The duct HEPA filters shall be located
on the downstream side of the supply air terminal unit. The selection of
the filters should be such that the air static pressure drop through it is
kept minimum.
(b) AIR DISTRIBUTION: The air distribution in the patient and recovery
rooms shall be such that only the supply air outlets shall be installed in
these occupied space. Exhaust of these rooms shall be through the
anterooms. The anterooms of the occupied spaces shall be ventilated by
installing the exhaust air inlets only. With this arrangement, the patient
room air would flow from the occupied spaces to the anterooms. The
anterooms shall also draw air from the adjacent corridor, and shall be
maintained under negative pressure with respect to the occupied areas and
corridors. The amount of air drawn from the corridors shall, however, be
relatively less and shall be only 10 percent of the air drawn from the
occupied spaces.
(c) AIR PRESSURE: Each patient and recovery room shall be kept under
positive pressure by retaining at least 15 percent of the supply air. To
ensure exact air balance, either an air flow control valve or a constant
volume box, with factory set air volume, shall be provided in the exhaust
air duct takeoff from each anteroom and all other exhaust air connections
of the dedicated system.
3.7 CT SCANNER
3.7.1 GENERAL
(a) The CT scanner has a function similar to the MRI unit; both being full
body tompgraphy units. The CT is, however, less sophisticated compared to
the MRI.
HVAC DESIGN MANUAL
3-4
HVAC REQUIREMENTS FOR OCCUPIED AREAS
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