Kidde Fire Systems DS Series, Application Manual

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K-76-1000 -30- July 2016
Controlling Smoke Spread
Smoke detectors placed in air ducts or plenums are not substitutes for open area smoke detectors.
Install the DS-PS detector in front of or behind the opening in return ducts. When the duct height exceeds
36 in. (91 cm), space the detectors per Table 5 below.
*
Note: Duct size is the greater of the width (horizontal dimension) or depth (vertical dimension)
1. Rigidly mount the detector within the air duct.
2. Permanently mark all duct detector locations and ensure that they are accessible for cleaning and
maintenance. See Figure 15 below.
Figure 15. Smoke Detector Spacing in Return Ducts
WARNING
Do not place heat detectors in air ducts.
Table 5. Location of Spot-Type Detectors in Return Air Duct Openings
Duct Size* Detector placement
Up to 36 in. (910 mm) One detector centered in the duct opening
Up to 72 in. (1.83 m) Two detectors located at the 1/4 points of the duct opening
Over 72 in. (1.83 m) One additional detector for each full 24 in. (610 mm) of duct opening
W Width
D Depth
Smoke detector
Note: One detector is required for each full
24 in. (610 mm) of additional opening
width.
Note: Keep the detectors spaced equally apart.
36 in. (910 mm) max.
36 in.
(910 mm)
max
36 in.
(910 mm)
max.
72 in. (1.83 m) max.
W/2
18 in.
(460 mm)
max.
18 in.
(460 mm)
max.
W/4 W/4
D/2 D/2
D/2 D/2
72 in. (1.83 m) 24 in. (610 mm)
.