Spot type smoke detectors located on the ceiling or, if on a sidewall, between the ceiling and ____ inches down from the ceiling to the top of the detector?

Spot type smoke detectors located on the ceiling or, if on a sidewall, between the ceiling and ____ inches down from the ceiling to the top of the detector?

• A. 4
• B. 6
• C. 8
• D. 12

Answer: (D)

Smoke rises and spreads along the ceiling, so spot-type detectors mounted on a sidewall must stay close to that ceiling to detect smoke early. The guideline is that the top of a sidewall detector should be within about 12 inches of the ceiling. In practice, many codes specify a range of roughly 4 to 12 inches below the ceiling, but the important point for this question is the maximum distance: 12 inches. Keeping the detector within this distance ensures smoke is captured promptly as it travels along the room, rather than being detected too far down the wall.

Smoke rises and spreads along the ceiling, so spot-type detectors mounted on a sidewall must stay close to that ceiling to detect smoke early. The guideline is that the top of a sidewall detector should be within about 12 inches of the ceiling. In practice, many codes specify a range of roughly 4 to 12 inches below the ceiling, but the important point for this question is the maximum distance: 12 inches. Keeping the detector within this distance ensures smoke is captured promptly as it travels along the room, rather than being detected too far down the wall.