FST Smoke Detection 5

Question 1

A duct smoke detector that shuts down the HVAC system upon activation is functioning as which type of control?

Accepted Answer

Smoke control

Answer

Duct smoke detectors that shut down HVAC fans are acting as smoke control devices, preventing the distribution of smoke through the ductwork system.

Question 2

What is the FIRST step a technician should perform when a smoke detector reports a 'trouble' condition at the fire alarm control panel?

Accepted Answer

Inspect wiring and the detector for loose connections, contamination, or cover removal

Answer

A trouble condition typically indicates a wiring fault, missing cover, loss of power, or internal fault; physical inspection is the correct first diagnostic step.

Question 3

Under NFPA 72, which type of signal does a smoke detector supervisory device in an HVAC system generate when smoke is detected?

Accepted Answer

Alarm signal

Answer

Duct smoke detectors initiate an alarm signal when smoke is detected, even though their primary function is HVAC control — they are alarm initiating devices.

Question 4

When installing smoke detectors in a compartment with a ceiling height of 14 feet, which NFPA 72 adjustment is required?

Accepted Answer

Reduce spacing based on the high-ceiling correction factor in NFPA 72 Annex A

Answer

NFPA 72 Annex A provides spacing reduction factors for ceiling heights above 10 feet to account for smoke dilution and stratification in taller spaces.

Question 5

Which scenario would MOST likely cause a carbon monoxide detector to activate but NOT a smoke detector?

Accepted Answer

A car left running inside an attached garage

Answer

A running vehicle produces high CO levels without significant visible smoke, triggering a CO detector while generating insufficient aerosol to activate a smoke detector.

(FST) Fire Safety Technician Certification Practice Test

(FST) Fire Safety Technician Certification Practice Test

FST Smoke Detection 5