Initiating Devices Flashcards

During the annual inspection of a fire alarm system, a smoke detector fails sensitivity testing. According to NFPA 72, the detector must be:

Answer: Cleaned and retested; replaced if it still fails

NFPA 72 allows detectors that fail sensitivity testing to be cleaned and retested; if they still fail after cleaning, they must be replaced.

What is the maximum allowable sensitivity range for a listed spot-type smoke detector?

Answer: 1.0% to 4.0% obscuration per foot

NFPA 72 requires that spot-type smoke detectors be calibrated and maintained within the manufacturer's listed sensitivity range, typically between 1.0% and 4.0% per foot obscuration per UL 268.

When testing a manual pull station, the technician should:

Answer: Pull it fully to verify it creates an alarm, then reset it with the appropriate tool

Manual pull stations must be physically operated to verify alarm initiation, and a reset key or tool is then used to restore the device to normal standby condition.

A fire alarm technician discovers that a smoke detector in a kitchen area is generating frequent nuisance alarms. The BEST corrective action is to:

Answer: Replace the ionization detector with a heat detector appropriate for a kitchen environment

Kitchens generate cooking vapors and aerosols that regularly cause nuisance alarms in smoke detectors; replacing with a heat detector rated for the environment is the correct code-compliant solution.

When performing a functional test of a duct smoke detector, the technician must verify that the detector:

Answer: Initiates an alarm signal AND shuts down the associated air handling unit

A duct smoke detector must both initiate an alarm signal at the FACP and trigger the associated HVAC unit shutdown to prevent smoke circulation through the building.

A fire alarm system initiating device circuit (IDC) in Class B configuration is also referred to as a:

Answer: Style B circuit

NFPA 72 designates Class B (formerly Style B or Style C) circuits as those that do not provide full fault isolation; a single open or ground fault disables part or all of the circuit.

A ground fault on an initiating device circuit should generate what type of signal at the fire alarm control panel?

Answer: Trouble signal

A ground fault on any supervised fire alarm circuit generates a trouble signal at the FACP, indicating a wiring fault that requires service but not necessarily an active fire condition.