Air Duct Housings

Features
8710, 8713 AND 8854B Detectors
Relay Model Available
Alarm LED Visible from Front
Designed for Air Velocity Range 100 to 4000 fpm
Clear Housing Cover Quick Identification of Detector Type
Cover removable with only four captive screws
UL Listed, CSFM Approved
9659
Introduction
FARADAY air duct detector housings are designed
to be used with 8700 Series and 8854B detectors.
Designed for installation directly to heating, ventilating
and air conditioning duct systems, they
comply with National Fire Protection Association
Standard No. 90A. When equipped with photoelectric
detectors, these units will signal the presence of
hazardous quantities of products of combustion or
smoke being carried through the duct system. Air
duct detectors are not intended to be substituted for
open area detection.
8742 and 8743 air duct housings are equipped with
relays. These relays are utilized to operate any
supplementary equipment when smoke or particles
of combustion are detected.
With MPC-6000 or 7000 control panels, up to 252
detectors per circuit having relays may be used.
Detection
These air duct housings are uniquely designed to
use the photoelectric detector.
Detector sensitivity may be viewed from the multicolor
LED on the detector or preferably may be
printed by command on an optional printer from the
control panel. The multi-color LED on the detector
flashes green to indicate the detector has passed
its self test and is within its proper sensitivity
8741, 8742 and 8743 Air Duct Housings
range. Yellow indicates either a Trouble condition
or an Out of Sensitivity condition. Red indicates
alarm.
The detector unit employs a cross-sectional sampling
principle of operation. Inlet sampling tubes
are available in four lengths (see table on reverse
side). Outlet sampling tubes are one common
length. A continuous cross-sectional sample of air
moving through the duct is taken. This averages the
effects of laminar flow, stratification or skin effect
phenomena occurring in the duct that could prevent
combustion product or smoke (especially in large
ducts) from reaching a spot type detector.
In addition, the unique design of the sampling
chamber insures uniform sensitivity in air velocities,
ranging from a low of 100 feet per minute to as
high as 4000 feet per minute.
The inlet sampling tube length is determined by the
width of the air duct being protected. The inlet tube
nearest to, but greater than the duct width, should
be used (see table). The inlet tube can then be
trimmed at the job site to the exact width of the
duct. The outlet sampling tube for all ducts,
irrespective of width, has a fixed length of
approximately 5 inches and is supplied with
the air duct housing.
These housings are UL listed and CSFM Approved
(3240-0065:191) NYMEA and FM are pending.
Siemens Building Technologies, Inc.
8 Fernwood Road Florham Park, NJ 07932
Tel: (973) 593-2600 Fax: (973) 593-6670

7/06 2.5M SBT/IG July 2006 - New Issue
Ordering Information
Duct Width Sampling Tube Model No.
6 to 1.0 ST-10
1.0 to 3.0 ST-25
3.0 to 5.0 ST-50
5.0 to 10.0 ST-100
Greater than 99 (292.5cm) Consult Faraday
Technical Support
ST-50 and ST-100 tubes require support.
Product Includes
One Short Return (outlet) Tube
One Stopper
Two #12 x 3/4 Sheet Metal Screws
Mounting Template
Note: Detector and sampling tube to be Purchased separately.
Sampling Tube Selection Table
Maintenance of the detector is easily accomplished
by the removal of the duct housing sampling chamber
cover. The detector, which plugs into the housing, is
easily removed for cleaning by a trained technician.
All that is necessary for the installation of the air duct
detector is the cutting of three small holes for the
sampling tube installation (template included) and the
drilling of four holes for mounting the air duct housing.
The unit is then easily mounted in place and
connection made to the existing wires or terminals if
optional accessories are utilized.
ST-50 and ST-100 require support. ST-100 is shipped in
two five foot pieces with a coupling for field assembly.
WARNING - The information contained in this document is intended only as a summary and
is subject to change without notice. The devices described in this document have specific
instruction sheets which cover various technical, limitation and liability information. Copies of
these instruction sheets and the General Product Warning and Limitations Document, which
also contains important information, are provided with the product and are available from the
Manufacturer. Information contained in these documents should be consulted before
specifying or using the product. For further information or assistance concerning particular
problems contact the Manufacturer.
Technical Data
Temperature Range 32