Spot type heat detector temperature ratings must be at least how many degrees Fahrenheit above the maximum temperature expected at ceiling level?

Spot type heat detector temperature ratings must be at least how many degrees Fahrenheit above the maximum temperature expected at ceiling level?

• A. 10°F
• B. 15°F
• C. 20°F
• D. 25°F

Answer: (C)

Spot-type heat detectors use a fixed temperature rating, so you must give them a buffer above the ceiling’s highest normal temperature to avoid nuisance alarms from ceiling heat. The required difference is 20°F, meaning the detector’s rating should be at least 20°F higher than the maximum temperature expected at ceiling level. This helps ensure the device only trips when actual fire heat pushes the area beyond normal ceiling temperatures. For example, if the ceiling could reach 100°F, choose a detector rated no lower than 120°F. Smaller margins like 10°F or 15°F wouldn’t provide enough buffer, while 25°F would exceed the minimum but isn’t the required minimum.

Spot-type heat detectors use a fixed temperature rating, so you must give them a buffer above the ceiling’s highest normal temperature to avoid nuisance alarms from ceiling heat. The required difference is 20°F, meaning the detector’s rating should be at least 20°F higher than the maximum temperature expected at ceiling level. This helps ensure the device only trips when actual fire heat pushes the area beyond normal ceiling temperatures. For example, if the ceiling could reach 100°F, choose a detector rated no lower than 120°F. Smaller margins like 10°F or 15°F wouldn’t provide enough buffer, while 25°F would exceed the minimum but isn’t the required minimum.