A 135°F fixed-temperature heat detector installed in a warehouse with nuisance alarms must have a temperature rating at least how many degrees Fahrenheit above the maximum expected ceiling temperature?

A 135°F fixed-temperature heat detector installed in a warehouse with nuisance alarms must have a temperature rating at least how many degrees Fahrenheit above the maximum expected ceiling temperature?

• A. 5
• B. 10
• C. 15
• D. 20

Answer: (D)

In fixed-temperature heat detectors, you want a buffer between the ceiling temperature you expect and the detector’s activation temperature to avoid nuisance alarms caused by normal temperature fluctuations or radiant heat. With a detector rated at 135°F, the safe margin is 20°F above the maximum expected ceiling temperature. That means the ceiling should not exceed 115°F, and the detector’s rating should be at least 20°F higher than that ceiling temperature. The 20°F difference minimizes false alarms in environments like a warehouse where heat can vary. Smaller margins (5°, 10°, or 15°F) don’t provide enough headroom and are more prone to nuisance alarms.

In fixed-temperature heat detectors, you want a buffer between the ceiling temperature you expect and the detector’s activation temperature to avoid nuisance alarms caused by normal temperature fluctuations or radiant heat. With a detector rated at 135°F, the safe margin is 20°F above the maximum expected ceiling temperature. That means the ceiling should not exceed 115°F, and the detector’s rating should be at least 20°F higher than that ceiling temperature. The 20°F difference minimizes false alarms in environments like a warehouse where heat can vary. Smaller margins (5°, 10°, or 15°F) don’t provide enough headroom and are more prone to nuisance alarms.