User guide

SS-400-006 2 I56-3535-002R
[4.1]VERIFY DUCT AIR FLOW DIRECTION AND VELOCITY
Model DNRHS detectors are designed to be used in air handling systems hav-
ing air velocities of 300 to 4000 feet per minute. Duct widths from 6 inches to
12 feet can be accommodated. Be sure to check engineering specifications to
ensure that the air velocity in the duct falls within these parameters. If neces-
sary, use a velocity meter (anemometer) to check the air velocity in the duct.
Each DNRHS duct smoke detector should be mounted as follows:
1. Location: Mount detector on the room side (up stream) of any air filter.
NOTICE: Mounting detector after filter may filter out smoke particles and
is not recommended.
2. Coverage: Each detector pipe length should be mounted along the longer
direction of the return air opening (length direction). One detector and
one standard, pre-drilled pipe length should be installed for every 2ft
of return air opening width. When more than one detector is required
(widths greater than 2ft.), detector housings should be staggered on op-
posite ends of the opening length. (refer to Figure 2).
3. Install detectors at the proper height within the duct/plenum per the
recommendations shown in Figure 3.
4. Hole Direction: holes facing directly into flow for positive pressure effect
5. Ensure adequate pressure differential across the detector housing accord-
ing to section 8.1 of this document.
[4.2]DETERMINE MOUNTING LOCATION AND CONFIGURATION
On ducts wider than 18 inches it is recommended that the detector be
mounted downstream of a bend, obstruction in the duct, or the supply or
return air inlet.
Exception: Installation of duct detectors can be on or within a commercial
packaged rooftop heating and air-conditioning system, fire/smoke dampers
and economizers. They may be mounted in either the supply and/or return air
section as determined by local code.
Once a suitable location is selected, determine if the detector is to be mounted
in a side-by-side “rectangular” configuration or a top-over-bottom “square”
configuration as shown in Figure 4. If mounting in the square configuration,
remove the rear attachment screw, rotate the unit at hinge, and replace the
screw into the new attachment hole as shown in Figure 4. Do NOT remove
the hinge screw during this process. Final installation approval shall be based
upon passing differential pressure and smoke entry tests described in the Mea-
surement Tests section.
[4.3]DRILL THE MOUNTING HOLES
Remove the paper backing from the mounting template supplied. Affix the
template to the duct at the desired mounting location. Make sure the template
lies flat and smooth on the duct.
[4.3.1]FOR RECTANGULAR SIDE-BY-SIDE MOUNTING CONFIGURATION:
Center punch at (4) target centers: (2) “A” for sampling tubes and (2) “B” for
the rectangular configuration mounting tabs as shown on mounting template.
Drill pilot holes at target “A” centers and cut two 1.375 inch diameter holes
using a 1
3
⁄8-inch hole saw or punch. Drill .156 inch diameter holes using a
5
⁄32
inch drill at target “B” centers.
[4.3.2]FOR SQUARE TOP-OVER-BOTTOM MOUNTING CONFIGURATION:
Center punch at (4) target centers: (2) “A” for sampling tubes and (2) “C” for
the square configuration mounting tabs as shown on mounting template. Drill
pilot holes at target “A” centers and cut two 1.375 inch diameter holes using
a 1
3
⁄8-inch hole saw or punch. Drill .156 inch diameter holes using a
5
⁄32 inch
drill at target “C” centers. If desired, drill an additional .156 inch hole at the
location of one of the mounting tabs on the lower housing.
C0931-00
3ft
1
2ft
CENTER
7ft
2ft
2
1
2
3
“LENGTH”
TYPIC
FIGURE 2. APPLICATION EXAMPLES:(VIEWED FROM ABOVE)
The DNRHS Air Duct Smoke Detector uses a 7251 laser smoke sensor. This
smoke detection method combined with an efficient housing design that
samples air passing through a duct provides early detection of a developing
hazardous condition. When sufficient smoke is sensed, an alarm signal is ini-
tiated at the fire control panel monitoring the detector, and appropriate action
can be taken to shut off fans and blowers, change over air handling systems,
etc. This can prevent the distribution or isolation of toxic smoke and fire gases
throughout the areas served by the duct system as well as provide an alert of
a developing hazardous condition in a facility.
Two LEDs on each detector latch ON to provide a local alarm indication. There
is also a remote alarm output for use with auxiliary devices. The DNRHS
has remote test capability with the RTS451/RTS151/RTS451KEY/RTS151KEY
Remote Test Station.
[2.1] DETECTOR FEATURE SET
– Utilizes plug-in head
– Sampling tubes install from front and rear
– Compatible with existing accessories
– Able to address detector per code switches on sensor head.
[3] CONTENTS OF THE DUCT SMOKE DETECTOR KIT
1. Sensor/power side and covers (use appropriate sensor per the system
control panel)
2. Three #10 sheet metal screws for mounting
3. Drilling template
4. One sampling tube end cap
5. One plastic exhaust tube
6. Laser Smoke Sensor
8. DCOIL Test Coil
[4] DETECTOR INSTALLATION
H0-616-00
FIGURE 3. PLENUM DIMENSION AND DETECTOR POSITION:
(VIEWED FROM SIDE)
H0-550-00
REMOVE SCREW AND PIVOT
DETECTOR AS SHOWN BELOW.
REPLACE SCREW
TO SECURE DETECTOR
IN PLACE.
FIGURE 4
NOTE: A DST sampling tube must be ordered to complete the installation. It
must be the correct length for the width of the duct where it will be installed. See
Table 1 on page 3 to determine the inlet tube required for different duct widths.