WARNING
Limitations of Duct Detectors
The National Fire Protection Association has established that DUCT DETECTORS MUST NOT BE USED AS A SUBSTITUTE FOR OPEN AREA DETECTOR PROTECTION as a means of providing life safety. Nor are they a substitute for early warning in a building’s regular fire detection system.
It is strongly recommended that the user read NFPA Standards 90A, 72, and 101.
![[1] Verify Duct Air Flow Direction And Velocity](/images/new-backgrounds/44334/443343xi3.webp){kind=small}
WARNING
This device will not operate without electrical power. Fire situations may cause an interruption of power. The system safeguards should be discussed with your local fire protection specialist.
![[2] Drill The Mounting Holes](/images/new-backgrounds/44334/443343xi4.webp){kind=small}
WARNING
This device will not sense smoke unless the ventilation system is operat- ing.
![[3] Secure The Detector Housing To The Duct](/images/new-backgrounds/44334/443343xi5.webp){kind=small}
WARNING
In order to function properly, this detector must be installed according to the instructions. Do not exceed the electrical or ambient specifications or the detector will not function properly. This detector must be protected from the elements.
Installation Sequence |
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Step 1. | Verify duct air flow direction and velocity | 2 |
Step 2. | Drill the mounting holes | 2 |
Step 2.1 | Install the sampling tube for ducts |
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| less than 11⁄2 feet (0.46m) wide | 2 |
Step 3. | Secure the detector housing to the duct | 2 |
Step 4. | Install the sampling tube for ducts |
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| greater than 11⁄2 feet (0.46m) wide | 2 |
Step 4.1 | Installation for ducts greater than 11⁄2 feet |
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| (0.46m) but less than 8 feet (2.4m) wide | 3 |
Step 4.2 | Installation for ducts more than 8 feet |
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| (2.4m) wide | 4 |
Step 5. | Install the filters | 4 |
Step 6. | Field wiring | 4 |
Step 7. | Perform detector check | 5 |
Step 8. | Install the cover | 5 |
Step 9. | Detector Maintenance and Test Procedures | 5 |
[1] Verify Duct Air Flow Direction And Velocity
The DH200RPL duct smoke detector is designed to be used in air han- dling systems having air velocities of 100 to 4000 feet per minute (0.5 to 20.32m/s). Be sure to check engineering specifications to ensure that the air velocity in the duct falls within these parameters. If necessary, use a velocity meter to check the air velocity in the duct. See Air Flow Test, section 9.1.
[2] 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. Center punch holes A and B. Drill the holes as indicated on the template.
[2.1] Sampling Tube Installation for Ducts Less Than 11⁄2 Feet (0.46m) Wide (see Figure 2)
1.Remove the front cover.
2.Slide the plastic sampling tube into the housing bushing.
3.Align the holes in the bushing with the holes in the sampling tube. Make sure there are 6 exposed holes on the plastic sampling tube. Secure with the #8
NOTE: For ducts greater than 11⁄2 feet (0.46m) in width, refer to sec- tions [4], [4.1] and [4.2].
[3] Secure The Detector Housing To The Duct
Slide the foam gaskets over the tube bushings as shown in Figure 3. Use the two 1 1⁄4″ long sheet metal screws to screw the detector housing to the duct.
CAUTION: Do not overtighten the screws.
[4]Sampling Tube Installation for Ducts Greater Than 11⁄2 Feet (0.46m) Wide
The sampling tube is identified by a series of air inlet holes on the tube. A plastic tube is included for ducts up to 11⁄2 feet (0.46m) wide. All other lengths must be purchased separately. Order the correct length, as speci- fied in Table 1, for width of the duct where it will be installed. It is recom- mended that the sampling tube length extend at least 2⁄3 across the duct width for optimal performance. The exhaust tube is molded onto the base of the duct housing, and the
The sampling tube is always installed with the air inlet holes facing into the air flow. To assist proper installation, the tube’s mounting flange is marked with an arrow. Make sure 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 installed and the air flows directly into the sampling tube holes as indicated in Figure 4.
Figure 2. Plastic sampling tube connected to duct smoke detector:
[4.1] Installation For Ducts Greater Than 11⁄2 Feet (0.46m) But Less Than 8 Feet (2.4m) Wide
1.If the tube is longer than the width of the air duct, drill a 3⁄4″ (19mm) hole in the duct opposite the hole already cut for the sampling tube. Make sure the hole is 1″ to 2″ (25 to 50mm) 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. (0.91m) long must be supported at the end opposite the duct smoke detector.
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