back-up air handling/cooling system for the telephone room when the
building environmental and cooling systems are inoperative. The backup
cooling system shall either be an air-cooled DX or an air-cooled
chilled water type with air handling unit and controls. See paragraph
2.12.9 for the dedicated refrigeration system. Consider the use of a
portable room humidifier if the steam humidification is not feasible.
Any pipe or duct system foreign to the telephone equipment installation
shall not pass through a telephone equipment room or a closet.
4.9 TRANSFORMER ROOMS (VAULTS) AND ELECTRIC CLOSETS
See paragraph 2.10.7 for ventilation requirements.
4.10 TRASH COLLECTION AREAS
See paragraph 2.10.4 for ventilation requirements.
4.11 WALK-IN REFRIGERATORS
4.11.1 GENERAL
See VA Master Specifications and Standard Details. Controlled
Temperature Rooms in laboratories or research are part of the equipment
purchased either directly by the VA or the Contractor, but not by the
mechanical contractor. Provide audible and visual temperature alarms
locally and at the ECC.
4.11.2 DESIGN PARAMETERS
Load calculations, heat gain factors, compressor running time, etc.,
shall be in accordance with ASHRAE Guide and Data books. Design
temperature shall be as follows:
Table 4-1 Design Temperatures, Degrees C (Degrees F), Walk-in
Refrigerators/Freezers
Refrigerator/Freezer Type
Temperatures Degrees C
(Degrees F)
Dairy Freezers
-29 (-20)
Ice Cream Freezers
-29 (-20)
Meat Freezers
-24 (-12)
Fresh Meat Refrigerators
0 (32)
Walk-in Refrigerators
2 (36)
Autopsy (Mortuary) Cold Rooms
2 (36)
Subsistence Storages (Supply Service)
2 (36)
4.11.3 FROST FORMATION AND FLOOR HEAVAGE PREVENTION
All freezers and meat refrigerators, on grade or above grade with fill,
shall have provisions to prevent frost formation and subsequent floor
heavage. The usual method is to provide heating cable (type Ml which
shall be shown on the electrical drawings) in the concrete sub-floor to
keep the ground from freezing. To conserve energy, some form of waste
heat using air or water, should be used in the anti-frost system
wherever possible.
HVAC DESIGN MANUAL
4-4
HVAC REQUIREMENTS FOR UNOCCUPIED AREAS
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