26 February 1993
equipped with a central chilled water plant, the dedicated chiller is
effect on animals is recommended. The VA requires fire
cross-connected with the central plant to allow the central plant to
sprinklers in all areas including animal rooms.
serve as the back-up.
ENGINEERING CONSIDERATIONS:
Emergency Power:
HVAC
The complete mechanical system, including the dedicated
An adequate heating, ventilating and air conditioning (HVAC)
chiller, should be connected to the emergency electrical power
system is a critical element in VMU design and requires careful
system to ensure a continuous electrical supply in the event of a
evaluation. The mechanical engineer should coordinate with the
power failure. Emergency power is required to operate the
architect and equipment designers to accommodate laboratory
mechanical system and thus maintain acceptable temperature
equipment specified for the project. Any request for deviation
and adequate ventilation in the animal rooms during power
from HVAC design criteria must be approved by VA and occur no
failures.
later than the design development stage.
The following
represents the highlights of the mechanical systems design for
Noise Levels:
the animal research facilities. Refer to the VA HVAC Design
Manual for further design requirements.
Animals and research equipment are sensitive to excessive
noise and vibrations. The noise level of NC 40 is recommended
HVAC System:
as the maximum permissible limit in the occupied spaces. Sound
A dedicated air handling unit should be provided to serve the
attenuation and vibration isolators for the mechanical system
following areas; however, consolidation of the areas/units for
should be provided where required. The masonry cavity of
small facilities may be allowed subject to VA approval:
interior walls may be filled with fiberglass inserts where sound
a. Animal Housing Areas
deadening is needed.
b. Animal Procedural and Administration Areas
c. Animal Surgical Area
Design Requirements:
Each air handling unit will operate 24 hours a day and should
Design should consider future requirements. Animal facility
use 100% outside air. Exhaust grilles for animal housing areas
HVAC systems should be independent of all other mechanical
should be located 7 inches above the floor level.
systems in the building. Mechanical design in animal rooms shall
Each room should have an individual room temperature
accommodate ventilated rack systems, individually ventilated
control. All animal room reheat coil hot water or steam valves
caging units, or site built or prefab cubicle units; depending on
MUST be of the FAIL OFF variety, rather than the FAIL ON
the system specified. The mechanical equipment should be
type.
located outside the VMU to avoid disturbances from noise and
Utilities:
vibration and to permit servicing the system without entering the
facility. The information listed on the Design Standards of this
Steam for heating and humidification is are typically provided
document's Sections 4, 5, 6, and 7 must be verified for each
from the central boiler plant. Cooling is accomplished by
project.
providing a dedicated chiller to serve the VMU. If the facility is
VA Design Guide -- Veterinary Medical Unit
Page 2-5
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