SYSTEM. Circuits operating at 100 Volts or less shall be defined as low
voltage and shall be run in rigid or flexible conduit, metallic tubing,
metal raceways or wire trays, or armored cable. Provide circuit and wiring
protection as required by NFPA 70. Aluminum-sheathed cable or aluminum
conduit may be used but shall not be buried in concrete. Use conduit or
plenum-rated cable in HVAC plenums. HVAC plenums include the space between
a drop ceiling and the architectural ceiling, within walls, and within
ductwork. Protect exposed wiring from abuse and damage.
2.4.3.1
AC Control Wiring
a.
Control wiring for 24 V circuits shall be insulated copper 18 AWG
minimum and rated for 300 VAC service.
b.
Wiring for 120 V shall be 14 AWG minimum and rated for 600 V
service.
2.4.3.2
Analog Signal Wiring
Analog signal wiring shall be 18 AWG single or multiple twisted pair. Each
cable shall be 100 percent shielded, and have 20 AWG drain wire. Each wire
shall have insulation rated to 300 V AC. Cables shall have an overall
aluminum-polyester or tinned-copper (cable-shield tape). Install analog
signal wiring in conduit separate from AC power circuits.
2.5
FIRE PROTECTION DEVICES
Provide smoke detectors in return and supply air ducts on downstream side
of filters in accordance with NFPA 90A, except as otherwise indicated.
Provide UL listed or FM approved detectors for duct installation.
2.5.1
Smoke Detectors
**************************************************************************
NOTE: Choose one of the three options below.
**************************************************************************
**************************************************************************
NOTE: Regarding text below, use this paragraph if
project has Section 13852, "Interior Fire Alarm
System."
**************************************************************************
[Provide in each air-handling system with supply air capacity greater than
944 L/s 2000 cfm in accordance with NFPA 90A. Locate downstream of the
supply air filters and prior to any branch connection in accordance with
NFPA 72. Provide in each air-handling system, serving more than one story,
and having a return air capacity greater than 7079 L/s 15000 cfm in
accordance with NFPA 90A. Locate at each story prior to connection to
common return and at return connection to air handler prior to any fresh
air inlet connection and prior to any recirculation connection in
accordance with NFPA 72. Furnish detectors under Section 13852, "Interior
Fire Alarm System," and install under this section.[ Smoke control and
exhaust systems shall have provision for [automatic and ]manual operation
by means of a key-operated switch to override any other shutdown features
and shall be located[ adjacent to the fire alarm system control panel][ as
indicated].]]
SECTION 15910N
Page 47
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