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
When is a smoke detector NOT required in an elevator machine room under NFPA 72?
Answer: When the elevator machine room is in a fully sprinklered building and sprinkler activation initiates recall
NFPA 72 and ASME A17.1 allow sprinkler activation alone to initiate elevator recall when the machine room is fully sprinklered, eliminating the smoke detector requirement for that function.
What does an obscuration level of 4% per foot indicate about a photoelectric smoke detector's listed sensitivity range?
Answer: The detector alarms at moderate smoke density within the typical listed range
NFPA 72 specifies that smoke detectors must be listed within a sensitivity range of 0.5% to 4% per foot obscuration, so 4% per foot is at the upper (least sensitive) end but still within the listed range.
Which spacing reduction factor applies to smoke detectors installed in a beam pocket ceiling where beams project more than 18 inches below the ceiling?
Answer: Treat each beam pocket as a separate ceiling compartment and space detectors accordingly
When beams project more than 18 inches below the ceiling, NFPA 72 requires treating each beam pocket as a separate ceiling compartment for detector spacing purposes.
What action should a fire safety technician take when a smoke detector consistently activates at low sensitivity but passes sensitivity testing?
Answer: Inspect and clean the detector, then retest
Consistent nuisance alarms at low conditions often indicate contamination; the correct first step is inspection and cleaning per manufacturer instructions before further action.
Which installation location is PROHIBITED for a standard spot-type smoke detector under NFPA 72?
Answer: In a bathroom with a shower
Bathrooms with showers are high-humidity environments where steam can cause false alarms; NFPA 72 does not require and advises against standard smoke detectors in these locations.
According to NFPA 72, what is the minimum number of smoke detectors required per sleeping room in a hotel or dormitory?
Answer: One per room
NFPA 72 requires at least one smoke detector in each sleeping room of hotels and dormitories to provide occupant notification at the point of occupancy.
What is the MAIN advantage of a dual-wavelength photoelectric smoke detector over a single-wavelength model?
Answer: Ability to discriminate between smoke and steam/dust to reduce false alarms
Dual-wavelength detectors use two light sources at different wavelengths to distinguish actual smoke particles from non-fire aerosols like steam and dust, reducing nuisance alarms.