Data Sheet for Product

Siemens
Smart Infrastructure - Building Products
–2–
usa.siemens.com/fire
Specifications (cont.)
The remote alarm indicator (Model FDBZ492-RTL) allows for manual testing via a key-switch for conventional and
addressable detectors, as well as the conventional and addressable air-duct housing with relay. Model FDBZ492-RTL,
which mounts remotely from the conventional and addressable air-duct housing, allows for manual relay-output control.
The duct-detector remote indicator key-switch also indicates the current state of the detector.
The watertight housing (Model FDBZ-WT), which allows the air-duct detector housing to be installed inside the separate
NEMA 4X enclosure, is for installations for either an outdoor area or in environments where excessive moisture is
prevalent.
Each detector unit employs a cross-sectional sampling principle of operation. Inlet sampling tubes are
available in four (4) lengths (see: Sampling Tube Selection Table). Outlet sampling tubes are one (1) common length
and draw. A continuous, cross-sectional sample of air moves through the duct. Stratification or skin affect phenomenon
that occurs in the duct can prevent smoke (especially in large ducts) from reaching a spot-type detector.
In addition, the unique design of the sampling chamber ensures uniform sensitivity in air velocities, ranging from a low of
100 fpm to as high as 4,000 fpm. Each air-duct housing comes with three (3) wiring entry ports:
▪ Two (2) 3/4” conduit knockouts
▪ One (1) 1/2” conduit opening
The inlet sampling tube length is determined by the width of the air duct being protected. The inlet tube ─ greater than
and nearest to the duct width ─ should be used (see: Sampling Tube Selection 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 5.5 inches (14cm.), and is supplied with the air-duct housing.
Note: When the use of a remote relay is required, order Model FDBZ492-R for conventional systems; Model
FDBZ492-HR for addressable systems. When required, a separate watertight enclosure (Model FDBZ-WT),
which is designed to contain the air-duct housings is available.
(For full details, refer to installation instructions for the respective air-duct housing.)
Note: When a self-contained duct detector with power supply is required, order Model FDBZ492-PR.
(For full details, refer to installation instructions - part number A6V10330327.)
Sampling Tube Selection Table
Duct Width
Sampling Tube
(Model No.)
For duct widths 6” to 1’
ST-10
For duct widths 1’ to 3’
ST-25
For duct widths 3’ to 5’
(requires support)
ST-50
For duct widths 5’ to 10’
(requires support)
ST-100
Maintenance of the detector is easily accomplished via the removal of the duct-housing sampling chamber cover.
The detector, which plugs into the housing, is easily removed for cleaning or replacing by a trained technician.
All that is necessary for installation of the air-duct detector is the cutting of three (3) small holes for the Sampling
Tube installation (template included), and the drilling of two (2) 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. No mechanical tools are required for removing the cover or connecting the sampling and exhaust
tubes to an air-duct housing.
Models ST-50 and ST-100 require support. However, Model ST-100 is shipped in two (2) 5-ft. (152 cm.) pieces with
a coupling for field assembly.