Fire Alarm System Operation Flashcards

A fire alarm system's secondary power supply (battery) must be capable of operating the system in standby mode for a minimum of how many hours, per NFPA 72?

Answer: 24 hours

NFPA 72 requires secondary power sufficient to operate the system in standby mode for 24 hours, followed by 5 minutes of alarm operation.

A duct smoke detector installed in an HVAC system is PRIMARILY intended to:

Answer: Detect smoke in the air stream and shut down the air handling unit to prevent smoke spread

Duct smoke detectors are designed to prevent HVAC systems from recirculating smoke throughout a building by shutting down the air handler upon detection.

Under NFPA 72, which entity has final authority over the installation and operation of a fire alarm system?

Answer: The authority having jurisdiction (AHJ)

The AHJ, typically the local fire marshal or building official, has final authority over fire alarm system compliance and operation under NFPA 72.

A waterflow switch on a wet-pipe sprinkler system sends a signal to the fire alarm control unit when:

Answer: Water flows through the system due to sprinkler operation or pipe break

A waterflow switch is activated by water movement in the sprinkler pipe, typically caused by a sprinkler head operating or a pipe failure.

When a fire alarm system is tested, notification appliances in occupied spaces must be:

Answer: Coordinated with occupants in advance and the AHJ notified before testing

Pre-notification of occupants and the AHJ before testing prevents unnecessary panic, unnecessary fire department dispatch, and undue disruption.

What is the purpose of a 'zone' in a conventional fire alarm system?

Answer: To divide the building into areas so a responding team can quickly locate the alarm source

Zones group initiating devices by area so responders can identify the approximate location of the detected condition without pinpointing an individual device.

A fire alarm system supervisor discovers that a pull station in a stairwell has been mechanically blocked by a piece of tape placed over it. The FIRST action should be:

Answer: Remove the obstruction immediately and investigate how it occurred

Obstructions to manual pull stations impair life safety and must be immediately removed; investigation follows to determine cause and prevent recurrence.