Exception: Terminal units in supply air duct for operating rooms shall be
unlined.
2.3.5 HVAC DRAINS
2.3.5.1 General
(a) All condensate from air conditioning equipment and other HVAC drains,
including cooling tower overflow and floor drains, shall discharge into the
sanitary sewer system.
(b) Drains from air conditioning equipment shall terminate, with an air gap,
above the flood level rim of plumbing fixtures, such as floor drain, floor
sink, sink, or open sight drain. Direct connection to the plumbing system
shall not be permitted.
(c) Open-sight drains are not permitted in concealed spaces.
2.3.5.2 Fan Coil Units, Run-around Heat Recovery Coils and Computer Room A/C
Units:
(a) These units shall have condensate drain lines, even if designed for
sensible cooling only.
2.3.5.3 Specific Requirements
(a) Avoid condensate drains discharging through outdoor walls, unless
specifically approved by the VA.
(b) Show all condensate drain piping on drawings including the drain traps.
See VA Standard Detail 15705-10.
(c) Minimum horizontal drain pipe shall be 20-mm (3/4-inch).
(d) Maximum horizontal run shall be 12 m (40 feet). Provide cleanouts in
drain piping.
(e) Provide a sufficient number of unit drain risers to permit a slope in the
horizontal drain lines of at least 25 mm (one inch) per 12 m (40 feet).
(f) Deep seal traps are required on air handling units. Proper installation
of these traps will typically require raising the air handling unit or
locating the traps below the floor level.
2.4 VARIABLE AIR VOLUME (VAV) SYSTEMS
2.4.1 GENERAL
(a) VAV systems shall be single duct with or without terminal, preferably hot
water reheat coils or dual duct type.
(b) All patient bedrooms and exterior and interior patient care areas, such
as treatment and examination rooms shall have reheat coils in the air
terminal units.
(c) Pressure-independent terminal units with factory set, but field
adjustable, maximum and minimum air volumes settings are required.
HVAC DESIGN MANUAL
2-9
HVAC SYSTEMS AND EQUIPMENT
Previous Page
