MIL-HDBK-1027/4A
require device area floor slab isolation from the rest of the facility.
Isolate the mechanical equipment room floor slabs from the remainder of the
facility.
2.2.5.4
Roof Loads. Mechanical equipment is preferred at ground level;
however, where roof mounting is necessary, design screening in accordance
with local wind loads and directional patterns. Anticipate other roof
structure mounted accessories, such as catwalks, ladders, hoists and cranes.
2.2.6
Heating, Ventilating and Air Conditioning. Comply with MIL-HDBK-
1003/3, Heating, Ventilating, Air Conditioning, and Dehumidifying Systems and
refer to MIL-HDBK-1008C for coordination with fire protection systems.
Provide 100 percent capacity back-up HVAC equipment to maintain critical
operations. Coordinate exterior mechanical equipment location with civil
design. Locate noisy chillers and other equipment remote from occupied
spaces and as near as possible to the mechanical spaces. Shade is desirable;
however, equipment should not be located beneath trees, where it can become
clogged with leaves and debris. Distribution piping for utilities, including
refrigerant and condenser water, should enter the building only through the
mechanical room. Avoid routing chilled water piping over computer areas and
trainer devices, to prevent damage to high cost equipment from leakage and
condensation. Provide isolation valves to facilitate maintenance without
system shutdown. Comply with Army TM5-805-4, Noise and Vibration Control,
where adjacent spaces and/or sensitive equipment cannot tolerate noise and
vibration. Special requirements for designated spaces follow:
Computer Rooms. Design spaces containing computers and other
electronic equipment requiring access flooring systems in compliance with the
Sections 4 and 8 of MIL-HDBK-1012/1, Electronic Facilities Engineering, and
Chapter 17 of the ASHRAE HVAC Applications Handbook. The most demanding air
conditioning requirement will be the computer room. A prime user complaint
is lack of cooling for critical and high cost computer equipment. Denser
equipment modules require more air volume and generate intensely concentrated
heat loads. Select HVAC units specifically designed for computer room
installation. Divide required capacity incrementally and provide multiple
units to match the load. Install one or more extra incrementally sized units
to allow for back-up. Computer equipment has a narrow range of operation
with regard to temperature and relative humidity. Operation outside of the
required range of temperature and relative humidity will cause damage and a
decrease in the life of components. The building HVAC system should
accommodate the personnel comfort and external environmental loads; however,
a dedicated system to handle computer equipment loads is essential. Computer
equipment is subject to revision and can easily overtax a building HVAC
system. A dedicated system will help accommodate future upgrades with
minimal impact on the building HVAC system. Provide methods for direct
cooling to equipment. Most computer cooling fans are near the bottom of the
equipment. Provide floor fed direct air. Avoid air current paths that
overcool the occupants while undercooling computer equipment. Typical
equipment units requiring direct fed cooling are freestanding computer
processing units and instructor/operator consoles.
Dust and particulate filtration systems may be required in the TFR
for the HVAC system to provide dust-free environment. Consider filters,
seals, positive pressures, forced air at entrances, and anterooms as
required.
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