Smoke Detection Flashcards
7 cards from real FST practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Smoke Detection flashcards as text
A duct smoke detector that shuts down the HVAC system upon activation is functioning as which type of control?
Answer: Smoke control
Duct smoke detectors that shut down HVAC fans are acting as smoke control devices, preventing the distribution of smoke through the ductwork system.
What is the FIRST step a technician should perform when a smoke detector reports a 'trouble' condition at the fire alarm control panel?
Answer: Inspect wiring and the detector for loose connections, contamination, or cover removal
A trouble condition typically indicates a wiring fault, missing cover, loss of power, or internal fault; physical inspection is the correct first diagnostic step.
Under NFPA 72, which type of signal does a smoke detector supervisory device in an HVAC system generate when smoke is detected?
Answer: Alarm signal
Duct smoke detectors initiate an alarm signal when smoke is detected, even though their primary function is HVAC control — they are alarm initiating devices.
When installing smoke detectors in a compartment with a ceiling height of 14 feet, which NFPA 72 adjustment is required?
Answer: Reduce spacing based on the high-ceiling correction factor in NFPA 72 Annex A
NFPA 72 Annex A provides spacing reduction factors for ceiling heights above 10 feet to account for smoke dilution and stratification in taller spaces.
Which scenario would MOST likely cause a carbon monoxide detector to activate but NOT a smoke detector?
Answer: A car left running inside an attached garage
A running vehicle produces high CO levels without significant visible smoke, triggering a CO detector while generating insufficient aerosol to activate a smoke detector.
What is the minimum required separation distance between a smoke detector and the nearest sprinkler head deflector under NFPA 72?
Answer: 18 inches horizontally
NFPA 72 requires smoke detectors to be installed at least 18 inches horizontally from any sprinkler deflector to prevent sprinkler water spray from directly impacting and damaging the detector.
Which document provides the primary installation and testing requirements for smoke detectors in commercial fire alarm systems in the United States?
Answer: NFPA 72 — National Fire Alarm and Signaling Code
NFPA 72 is the primary national standard governing the installation, testing, inspection, and maintenance of fire alarm and signaling systems including smoke detectors.