Kidde Fire Systems DS Series, Application Manual

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July 2016 -19- K-76-1000
Beams and Solid Joists
For smoke detector spacing, solid joists are considered equivalent to beams.
For ceilings with a beam or solid joist depth less than 10 percent of the ceiling height (0.1 H), mount the
detectors on the bottom of beams.
For ceilings with a beam or solid joist depth equal to or greater than 10 percent of the ceiling height
(0.1 H) and a beam spacing equal to or greater than 40 percent of the ceiling height (0.4 H), locate the
detectors on the ceiling in each beam pocket.
For ceilings with a beam depth equal to or greater than 10 percent of the ceiling height (0.1 H) and a beam
spacing less than 40 percent of the ceiling height (0.4 H), locate the detectors either on the bottom of the
beams or on the ceiling at smooth ceiling spacing in the direction parallel to the beams and at one-half
smooth ceiling spacing in the direction perpendicular to the beams.
Figure 11. Smoke Detector Spacing for Beam Construction
H = Ceiling Heights 1 < 1.0 H
2. ≥ . 0.1 H and ≥ . 0.4 H
3. ≤ 0.1 H and ≥ . 0.4 H
4. Side view
5. Ceiling Section
6. Heat detector
7. Solid beam
≥
0.4 H
≤
0.4 H
5
5
5
1
6
6
6
6
2
3
7
7
7
4
4
4