When testing a room temperature switch, below what temperature does the off-normal signal occur?

Room temperature switches are used to detectfreezing conditionsin environments such as sprinkler valve rooms. An off-normal (supervisory) condition is triggered if the temperature dropsbelow 40 °F (4.4 °C).

NFPA 72 (2022), Section A.17.16.1.1:

“Low-temperature supervisory signals shall be initiated when the temperature falls below 40 °F (4.4 °C) unless otherwise specified.”

This signal helps prevent system damage or failure due to freezing.

Correct answer: B. 40 °F (4.4 °C)

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