electronic. Control wiring and tubing required to complete the space
temperature control system shall be included.
2.3.3.1
Air Compressor
Where pneumatic controls are furnished, an air compressor of the standard
piston type shall be provided complete with air tanks, air dryer, and other
appurtenances. Compressor and installation shall comply with ASME B19.3.
Compressor shall be of sufficient capacity to provide continuous control
air when operating on a 1/3-on 2/3-off cycle and shall be provided with a
visible oil-level sight glass and oil filter. Air dryers shall be of the
silicagel type with reactivation, or of the refrigerated type, and shall
maintain the air in the system with a dew point low enough to prevent
condensation (minus 11 degrees C 13 degrees F at 125 kPa 18 psi main
pressure). Air dryer shall be located at the outlet of the tank. A
standby compressor of capacity equal to the basic compressor shall be
provided with interlocked control system to provide automatic changeover
upon the malfunction or failure of basic compressor. A manual selector
switch shall be provided to index the lead compressor including the
automatic changeover.
2.3.3.2
Air Lines
Air lines for pneumatic controls shall be seamless copper tubing or
nonmetallic tubing. Piping shall be concealed except in mechanical rooms
or areas where other piping is exposed. Copper tubing shall be hard-drawn
in exposed areas and either hard-drawn or annealed in concealed intervals
and shall run parallel to the lines of the building. Only tool-made bends
will be acceptable. Fittings for copper tubing shall be brass or copper
solder joint-type except at connections to apparatus, where fittings shall
be brass compression-type. Nonmetallic tubing shall be polyethylene,
meeting the stress crack test of ASTM D 1693. Individual tube polyethylene
or multitube instrument tubing bundle shall be classified as flame
retardant under UL 94 and the polyethylene material shall be rated as
self-extinguishing when tested in accordance with ASTM D 635. Nonmetallic
tubing shall be run within securely supported rigid metallic raceway or
electric metallic tubing except as indicated. Single nonmetallic tubing in
a protective sheath may be used above accessible ceilings and in other
concealed accessible locations. Tubing concealed in walls containing
insulation, fill, or other packing materials shall be hard-drawn copper
tubing or nonmetallic tubing run in conduit. Terminal single lines shall
be hard-drawn copper tubing, except if the run is less than 300 mm 12 inches,
flexible polyethylene may be used. Nonmetallic tubing shall not be used
for applications where the tubing could be subjected to a temperature
exceeding 55 degrees C 130 degrees F. Multitube instrument bundle may be
used in place of single tube where a number of tubes run to the same
points. Tubing shall be periodically tested for leaks during installation
and all tubing shall be free of installation impurities and moisture before
connecting to the control instrument. Fittings for polyethylene tubing
shall be for instrument service and may be brass or acetal homopolymer of
the compression or barb push-on type. Tubing shall be number coded or
color coded and keyed to the submittal drawings for future identifying and
servicing of the control system.
2.3.3.3
Room Thermostats
Thermostats shall be standard commercial type with an adjustable
differential and a set-point range of [15 to 30 degrees C 60 to 90 degrees F
] [5 to 20 degrees C 40 to 70 degrees F].
SECTION 15562A
Page 20
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