S95 - Supervision of Fire Alarm System System Components and Power Questions and Answers 1 — Questions and Answers
Question 1: According to NFPA 72, what is the minimum required capacity for the secondary power supply (batteries) for a standard, non-voice fire alarm system?
- 12 hours of operation in standby, followed by 5 minutes in alarm.
- 24 hours of operation in standby, followed by 15 minutes in alarm.
- 48 hours of operation in standby, followed by 5 minutes in alarm.
- 24 hours of operation in standby, followed by 5 minutes in alarm. (Correct answer)
Correct answer: 24 hours of operation in standby, followed by 5 minutes in alarm.
NFPA 72 requires the secondary power supply to have enough capacity to operate the fire alarm system under normal (quiescent) load for a minimum of 24 hours, and then operate all alarm notification appliances for at least 5 minutes. The 15-minute alarm requirement applies to systems with voice evacuation capabilities.
Question 2: Which of the following best describes the primary power source for a Fire Alarm Control Panel (FACP)?
- A shared circuit with emergency lighting to ensure it is always prioritized.
- Any 120V outlet within 6 feet of the panel.
- A dedicated branch circuit with a marked and locked circuit breaker. (Correct answer)
- A Ground-Fault Circuit Interrupter (GFCI) protected outlet.
Correct answer: A dedicated branch circuit with a marked and locked circuit breaker.
To ensure reliability and prevent accidental deactivation, NFPA 72 and the National Electrical Code (NEC) require the FACP to be powered by a dedicated branch circuit. This circuit's breaker must be clearly marked as 'FIRE ALARM' and secured with a lock or other approved means to prevent it from being turned off accidentally.
Question 3: In an addressable fire alarm system, what is the function of a Signaling Line Circuit (SLC)?
- It exclusively powers notification appliances like horns and strobes.
- It creates a simple zoned circuit where the panel only knows the general area of an alarm.
- It allows for two-way communication between the control panel and individually identified devices. (Correct answer)
- It provides the 24V DC backup power from the batteries to the main panel.
Correct answer: It allows for two-way communication between the control panel and individually identified devices.
A Signaling Line Circuit (SLC) is the backbone of an addressable system. It's a data circuit that allows for two-way communication, enabling the control panel to poll each device for its status and for each device (like a smoke detector or pull station) to report its specific address and condition (normal, alarm, trouble) back to the panel.
Question 4: An S-95 holder is working in a large building where the main FACP is in the basement. A separate panel in the lobby displays the system status and indicates the floor of any alarm. What is this lobby panel called?
- A Remote Annunciator. (Correct answer)
- A NAC Power Expander.
- A Main Terminal Cabinet.
- A Zone Disconnect Switch.
Correct answer: A Remote Annunciator.
A remote annunciator is a secondary display for the fire alarm system. It is placed in a location, such as a lobby or security office, to provide first responders and building personnel with convenient access to critical system information without having to go to the main FACP.
Question 5: Which wiring configuration provides redundancy by creating a complete loop from the control panel, through all devices, and back to the panel, allowing it to function despite a single break in the line?
- Class B.
- Class X.
- Class A. (Correct answer)
- Class C.
Correct answer: Class A.
Class A wiring creates a redundant path. The circuit starts at the panel, goes to all the devices in a series, and then returns to the panel on a separate pair of wires. This loop ensures that if a single open occurs on the circuit, no devices are lost, as the panel can still communicate with them from both directions of the loop.
Question 6: A fire alarm system design for a large school requires more horns and strobes than the main FACP can power. Which component would be installed to provide additional, synchronized power for these notification appliances?
- A larger set of backup batteries.
- An addressable control module.
- An uninterruptible power supply (UPS).
- A NAC power supply / booster panel. (Correct answer)
Correct answer: A NAC power supply / booster panel.
A Notification Appliance Circuit (NAC) power supply, also known as a booster panel, is used to provide additional power for notification appliances like horns and strobes. It augments the power capabilities of the main FACP and ensures all visual appliances can be properly synchronized per NFPA 72 requirements.
S95 - Supervision of Fire Alarm System System Components and Power Questions and Answers 1
According to NFPA 72, what is the minimum required capacity for the secondary power supply (batteries) for a standard, non-voice fire alarm system?