When heat detectors are used to shut down elevator power prior to sprinkler operation, the detector shall have both a ________ ________ ___________ and a __________ _____________ as compared to the sprinkler.

When heat detectors are used to shut down elevator power prior to sprinkler operation, the detector shall have both a ________ ________ ___________ and a __________ _____________ as compared to the sprinkler.

• A. lower temperature rating and higher sensitivity
• B. higher temperature rating and lower sensitivity
• C. equal temperature rating and equal sensitivity
• D. lower temperature rating and lower sensitivity

Answer: (A)

The key idea is that the heat detector must respond before the sprinkler does, so the elevator power can be shut off in time. To ensure this, the detector is configured with a lower temperature rating and higher sensitivity than the sprinkler. A lower temperature rating means it will trip at a lower heat level, and higher sensitivity means it responds more readily to heat. Together, these make the detector activate first, ahead of the sprinkler, enabling a safe shutdown of elevator power. If a higher temperature rating were used, activation would occur after the sprinkler, defeating the purpose. Equal ratings would lead to the same timing as the sprinkler. A lower temperature rating with lower sensitivity could still miss a rapid heat rise, delaying shutdown.

The key idea is that the heat detector must respond before the sprinkler does, so the elevator power can be shut off in time. To ensure this, the detector is configured with a lower temperature rating and higher sensitivity than the sprinkler. A lower temperature rating means it will trip at a lower heat level, and higher sensitivity means it responds more readily to heat. Together, these make the detector activate first, ahead of the sprinkler, enabling a safe shutdown of elevator power.

If a higher temperature rating were used, activation would occur after the sprinkler, defeating the purpose. Equal ratings would lead to the same timing as the sprinkler. A lower temperature rating with lower sensitivity could still miss a rapid heat rise, delaying shutdown.