Duct smoke detectors must be inspected visually to check for cleanliness, mounting condition, and airflow alignment. The minimum frequency isquarterly.
NFPA 72 (2022), Table 14.3.1 - Visual Inspection Frequencies:
"Duct detectors (smoke)" # Frequency: Quarterly
This helps ensure proper functionality in HVAC systems.
Correct answer: B. Quarterly

Forsealed lead-acid batteries, NFPA 72 specifies that their condition be verified by checkingspecific gravity
, which indicates battery charge status and health.
NFPA 72 (2022), Table 14.4.3.2 - Testing Methods:
Lead-acid batteries shall be tested semiannually by measuring specific gravity.
If batteries are sealed and specific gravity cannot be tested, voltage and visual checks are used instead.
Correct answer: C. By verifying specific gravity

Control valve supervisory switches must be tested to verify that they send a signal when the valve position changes (e.g., valve is closed). NFPA 72 requires this to be doneannually.
NFPA 72 (2022), Table 14.4.3.2 - Testing Frequencies:
Control valve supervisory switch:
Frequency:Annually
Method:Operate valve control; verify signal annunciation.
Correct answer: D. Annually

Household fire alarm systems have different performance requirements from commercial systems, but still must support essential alarm functions under loss of primary power.
NFPA 72 (2022), Section 29.10.5.1.1:
"The secondary power supply shall be capable of powering the system under quiescent load for 24 hours and then capable of operating the system during alarm for a period of 4 minutes (for general fire alarm) or 10 minutes (for household fire alarm systems)." Correct answer: C. 24 hours in the normal condition followed by 10 minutes of alarm

In aClass Afire alarm circuit, asingle opencondition does not affect communication but must still be annunciated as atroublesignal.
NFPA 72 (2022), Section 12.3.1.1.1.4:
"A single open condition on a Class A pathway shall result in a trouble signal." This maintains system operation while alerting of a wiring fault.
Correct answer: D. Trouble