FDNY S78 CERTIFICATE OF FITNESS –
CLEANING & TESTING OF SMOKE
DETECTORS PRACTICE EXAM
QUESTIONS AND CORRECT ANSWERS
(VERIFIED ANSWERS) PLUS RATIONALES
2026 Q&A | INSTANT DOWNLOAD PDF
1. What is the primary purpose of cleaning smoke detectors?
A. Improve aesthetics
B. Reduce false alarms
C. Increase power consumption
D. Disable the detector
Answer: B
Rationale: Cleaning smoke detectors removes dust and debris that can
cause false alarms or impair functionality.
2. How often should smoke detectors in commercial buildings be
cleaned?
A. Monthly
B. Quarterly
C. Annually
D. Every five years
Answer: C
Rationale: FDNY requires annual cleaning to ensure detectors operate
reliably.
,3. Which type of smoke detector is most sensitive to small smoke
particles?
A. Ionization
B. Photoelectric
C. Heat
D. Combination
Answer: B
Rationale: Photoelectric detectors are highly responsive to smoldering
fires with small particles.
4. Before cleaning a smoke detector, what must you do?
A. Disconnect power or battery
B. Spray water on it
C. Remove it from the ceiling without precautions
D. Cover the detector in plastic
Answer: A
Rationale: Disconnecting power prevents false alarms and protects the
technician from electrical shock.
5. What should be used to clean a smoke detector?
A. Compressed air or vacuum
B. Water and detergent
C. Sandpaper
D. Oil-based cleaners
Answer: A
Rationale: Compressed air or a vacuum safely removes dust without
damaging the detector.
6. What is the FDNY-required testing interval for smoke detectors?
A. Daily
B. Monthly
C. Annually
, D. Every two years
Answer: B
Rationale: Monthly functional testing ensures detectors respond
correctly to smoke.
7. Which of the following is a sign a smoke detector may need
cleaning?
A. Frequent false alarms
B. Discoloration
C. Dust accumulation
D. All of the above
Answer: D
Rationale: All these signs indicate the detector may be compromised by
dust or debris.
8. When testing a smoke detector, which method is recommended?
A. Spray water
B. Use smoke aerosol tester
C. Hit the detector
D. Spray oil-based cleaner
Answer: B
Rationale: Smoke aerosol testing simulates real smoke conditions
safely.
9. What is the safest way to handle a detector during cleaning?
A. Pull it down forcefully
B. Handle gently, avoiding internal components
C. Immerse it in water
D. Disassemble fully
Answer: B
Rationale: Detectors are delicate, and rough handling may damage
sensors.
CLEANING & TESTING OF SMOKE
DETECTORS PRACTICE EXAM
QUESTIONS AND CORRECT ANSWERS
(VERIFIED ANSWERS) PLUS RATIONALES
2026 Q&A | INSTANT DOWNLOAD PDF
1. What is the primary purpose of cleaning smoke detectors?
A. Improve aesthetics
B. Reduce false alarms
C. Increase power consumption
D. Disable the detector
Answer: B
Rationale: Cleaning smoke detectors removes dust and debris that can
cause false alarms or impair functionality.
2. How often should smoke detectors in commercial buildings be
cleaned?
A. Monthly
B. Quarterly
C. Annually
D. Every five years
Answer: C
Rationale: FDNY requires annual cleaning to ensure detectors operate
reliably.
,3. Which type of smoke detector is most sensitive to small smoke
particles?
A. Ionization
B. Photoelectric
C. Heat
D. Combination
Answer: B
Rationale: Photoelectric detectors are highly responsive to smoldering
fires with small particles.
4. Before cleaning a smoke detector, what must you do?
A. Disconnect power or battery
B. Spray water on it
C. Remove it from the ceiling without precautions
D. Cover the detector in plastic
Answer: A
Rationale: Disconnecting power prevents false alarms and protects the
technician from electrical shock.
5. What should be used to clean a smoke detector?
A. Compressed air or vacuum
B. Water and detergent
C. Sandpaper
D. Oil-based cleaners
Answer: A
Rationale: Compressed air or a vacuum safely removes dust without
damaging the detector.
6. What is the FDNY-required testing interval for smoke detectors?
A. Daily
B. Monthly
C. Annually
, D. Every two years
Answer: B
Rationale: Monthly functional testing ensures detectors respond
correctly to smoke.
7. Which of the following is a sign a smoke detector may need
cleaning?
A. Frequent false alarms
B. Discoloration
C. Dust accumulation
D. All of the above
Answer: D
Rationale: All these signs indicate the detector may be compromised by
dust or debris.
8. When testing a smoke detector, which method is recommended?
A. Spray water
B. Use smoke aerosol tester
C. Hit the detector
D. Spray oil-based cleaner
Answer: B
Rationale: Smoke aerosol testing simulates real smoke conditions
safely.
9. What is the safest way to handle a detector during cleaning?
A. Pull it down forcefully
B. Handle gently, avoiding internal components
C. Immerse it in water
D. Disassemble fully
Answer: B
Rationale: Detectors are delicate, and rough handling may damage
sensors.
