Det-Tronics U5006 Air Duct Smoke Detector - Manual (Page 3)

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ENGINEERING SPECIFICATIONS
The air duct photoelectric smoke detector shall lock in on
alarm and have an alarm indicator LED visible through
the air sampling chamber cover. Detectors shall be
mounted exterior to the duct, with perforated sampling
tubes. Activation of a detector shall cause shutdown
of associated equipment through the control circuitry of
the fire alarm panel. The detector shall be mounted in a
readily accessible location.
The detector shall have SPST alarm contacts for the fire
alarm control panel and power supervision. In addition,
the detector shall be capable of activating a remote
indicating lamp on a remote annunciator.
The detector unit shall be designed for use in Class I,
Division 2, Groups A, B, C and D hazardous locations. A
junction box shall be furnished for connecting the system
wiring.
INSTALLATION
The U5006 Air Duct Smoke Detector mounts externally
on any duct wall with the air sampling and return air
tubes extending into the duct to provide a continuous
cross sectional sampling of the air moving through the
air handling system. Electrical equipment that is used in
conjunction with the smoke detector is connected to the
detector using a terminal strip located in the junction box
that is furnished with the unit.
NOTE
To prevent ignition of a hazardous atmosphere,
either de-classify the area or remove power from
the unit before opening the enclosure or junction
box.
Detector Location
Detectors can be mounted in the supply system
downstream of the filters or in the return system at the
point of entry into a common return duct. Whenever
possible, detectors that are mounted on a return duct
should be at a distance equivalent to six duct widths from
any duct openings, sharp bends, branch connections, or
deflection plates.
For additional information regarding the location and
spacing of duct smoke detectors, contact the National
Fire Protection Association, Batterymarch Park, Quincy,
MA 02269 and request a copy of NFPA Standard 90A,
Installation of Air Conditioning and Ventilation Systems
and NFPA Standard 72 for Automatic Fire Detectors.
MoUnting the Detector
Select the location for mounting the detector. 1.
Mark and drill the appropriate mounting and sampling 2.
tube holes on the duct wall. Refer to Figure 2 to
determine the size and location of the holes.
NOTE
To ensure proper operation of the sampling tube
within the air duct, be sure to observe proper
sampling and return tube position and orientation
as illustrated in Figure 3.
Attach the return tube to the detector housing by 3.
sliding the tube into the connector body and rotating
the tube until the key notch slips over the alignment
pin in the connector. The opening at the end of the
tube is cut at an angle. This opening must always
face downstream or away from the direction of air
flow in the duct, as shown in Figure 3. Tighten the
compression nut until the tube is stable.
The sampling tube is available in 1, 3, 6, and 10 foot
4.
lengths. As a rule, order the tube that is capable of
spanning the entire width of the air duct. For duct
widths of three feet or smaller, the sampling tube may
be cut to three quarters of the duct width. For duct
widths greater than three feet, the recommended
practice is to drill a hole on the duct wall directly
across from the sampling tube hole of the duct
detector. This provides the required support and
eliminates excessive stress on the compression nut
of the sampling tube connector. Be sure to seal any
gap around the hole to prevent air leakage.
NOTE
When cutting a sampling tube, always cut the end
opposite the notches. If the end with the notches
is cut, the tube will not seat in the connector
fitting properly and proper orientation may not be
possible. When the sampling tube is cut to the
proper length, install the rubber plug snugly in
the end of the tube.
To assure proper detector
operation, it is essential that the rubber plug be
installed at the end of the sampling tube.
Attach the sampling tube to the detector housing 5.
using the compression nut on the connector in the
same way that the return tube was installed. Tighten
the compression nut until the tube is stable.
NOTE
The holes in the sampling tube must face the air
flow in the duct.