the sampling tube is mounted so that the arrow points into the air flow
(see Figure 4). Figure 5 shows the various combinations of tube mounting
configurations with respect to air flow. Mounting the detector housing in a
vertical orientation is acceptable, provided that a metal sampling tube is
used and the air flows directly into the sampling tube holes as indicated
in Figure 4.
[4.1] Installation For Ducts Greater Than 1
1⁄ 2
Feet But Less Than
8 Feet Wide
1.
If the tube is longer than the width of the air duct,
drill a
3
⁄ 4
″
hole in the
duct opposite the hole already cut for the sampling tube. Make sure the
hole is 1
″
to 2
″
below the inlet hole on the opposite side of the duct to
allow moisture drainage away from the detector.
If the tube is shorter
than the width of the air duct,
install the end cap into the sampling tube
as shown in Figure 4. Sampling tubes over 3 ft. long must be supported
at the end opposite the duct smoke detector.
2. Slide the tube into the housing bushing that meets the air flow first.
Position the tube so that the arrow points into the air flow, as shown
in Figure 4.
3. Secure the tube flange to the housing bushing with two #6 self-tapping
screws.
4. For tubes longer than the width of the air duct, the tube should extend
out of the opposite side of the duct. If there are more than 2 holes in
the section of the tube extending out of the duct, select a different
length using Table 1. Otherwise, trim the end of the tube protruding
through the duct so that 1
″
to 2
″
of the tube extend outside the duct.
Plug this end with the end cap and tape closed any holes in the pro-
truding section of the tube. Be sure to seal the duct where the tube
protrudes.
NOTE:
The sampling tube end cap is critical to the proper operation of
the duct smoke detectors. The end cap is needed to create the
proper air flow to the sensor of the duct smoke detector.
Table 1. Sampling tubes recommended for different
duct widths:
Outside Duct Width
Sampling Tube Recommended*
1 to 2 ft. (0.3 to 0.6 m)
ST-1.5
2 to 4 ft. (0.6 to 1.2 m)
ST-3
4 to 8 ft. (1.2 to 2.4 m)
ST-5
8 to 12 ft. (2.4 to 3.7 m)
ST-10
*Must extend a minimum of
2
⁄
3
the duct width
J500-42-00
3
I56-2198-003R
SCREW HOLES FOR
ATTACHING HOUSING
TO DUCT WORK.
Figure 3. Installation of foam gaskets over
sampling tube bushings:
Figure 5. Tube mounting configurations with varying
air flow direction:
SAMPLING
TUBE
END CAP
AIR HOLES
ARROW
MUST FACE
INTO AIR FLOW
AIR FLOW DIRECTION
FLANGE
Figure 4. Air duct detector sampling tube:
AIR FLOW
DIRECTION
DETECTOR
HOUSING
DOTS INDICATE POSITION OF
SAMPLING TUBE HOLES
AIR FLOW
DIRECTION
DETECTOR
HOUSING
SAMPLING
TUBE
EXHAUST
TUBE
AIR FLOW
DIRECTION
EXHAUST
TUBE
SAMPLING
TUBE
SAMPLING
TUBE
EXHAUST
TUBE
DETECTOR
HOUSING
AIR FLOW
DIRECTION
DETECTOR
HOUSING
A.
B.
C.
D.
HORIZONTAL MOUNTING OF HOUSING
VERTICAL MOUNTING OF HOUSING
NOTE: Only metal sampling tubes can be installed in
orientations C and D.
H0107-00
H0108-02
H0109-01
[4.2] Installation For Ducts More Than 8 Feet Wide
NOTE:
To install sampling tubes in ducts more than 8 feet wide, work
must be performed inside the air duct. Sampling of air in ducts
wider than 8 feet is accomplished by using the ST-10 sampling
tube. If the tube is shorter than the width of the air duct, install
the end cap into the sampling tube as shown in Figure 4 and
support the end opposite the duct smoke detector.
Install the sampling tube as follows:
1. Drill a
3
⁄4
-inch hole in the duct directly opposite the hole already drilled
for the sampling tube. Make sure the hole is 1
″
to 2
″
below the inlet
hole on the opposite side of the duct to allow for moisture drainage.
2. Slide the sampling tube with the flange into the housing bushing that
meets the air flow first. Position the tube so that the arrow points into
the air flow. Secure the tube flange to the housing bushing with two
#6 self-tapping screws.
3. From inside the duct, couple the other sections of the sampling tube
to the section already installed using the
1
⁄ 2
-inch conduit fittings sup-
plied. Make sure that the holes on both of the sampling tubes are lined
up and facing into the air flow.
4. Trim the end of the tube protruding through the duct so that 1
″
to 2
″
of
the tube extend outside the duct. Plug this end with the end cap and
tape closed any holes in the protruding section of the tube. Be sure to
seal the duct where the tube protrudes.
