Initiating Devices Flashcards

A fixed-temperature heat detector activates when the ambient temperature at the device reaches a predetermined level. What is the most common fixed-temperature rating for standard applications?

Answer: 135°F (57°C)

The most common fixed-temperature rating for standard environments is 135°F (57°C), which is low enough to detect abnormal heat while remaining above typical ambient temperatures.

A rate-of-rise heat detector triggers an alarm when the temperature increases by more than how many degrees Fahrenheit per minute?

Answer: 25°F per minute

Rate-of-rise detectors are designed to alarm when temperature increases at a rate exceeding approximately 12–15°F per minute, indicating a rapidly developing fire condition.

Which type of heat detector is MOST appropriate for an environment where slow-smoldering fires are expected but ambient temperatures may already be high?

Answer: Fixed-temperature detector at a higher rating

In high-ambient-temperature environments, a fixed-temperature detector set at an appropriately higher rating ensures the detector does not false-alarm while still responding to an actual fire.

After activation, which type of heat detector must be replaced rather than reset?

Answer: Fusible-link or fusible-alloy fixed-temperature detector

Fusible-link or fusible-alloy detectors operate by melting an alloy at a set temperature; once activated, the element is destroyed and the entire detector must be replaced.

A manual pull station must be installed at what height above the finished floor per NFPA 72?

Answer: Between 42 and 54 inches

NFPA 72 requires manual pull stations to be mounted with the operable part between 42 inches (3.5 ft) and 54 inches (4.5 ft) above the finished floor.

Where must a manual pull station be located relative to a building exit?

Answer: Within 5 feet of the exit door on the egress side

NFPA 72 requires manual pull stations to be located within 5 feet of the exit door on the path of egress so occupants can activate the alarm as they exit.

A double-action manual pull station requires the user to perform what sequence before it activates?

Answer: Lift a cover and then pull the handle

Double-action pull stations require lifting, breaking, or opening a protective cover before the handle can be pulled, reducing accidental activations.