Supervisory and Trouble Signals Flashcards

A building's Fire Alarm Control Panel (FACP) indicates a 'Ground Fault' condition. According to NFPA 72, which type of signal is this, and what is the implication?

Answer: A trouble signal, indicating a fault within the fire alarm system's wiring or components.

A 'Ground Fault' is an unwanted connection between a system conductor and ground, which indicates a wiring problem within the fire alarm system itself. NFPA 72 defines this as a 'trouble' condition, as it signifies a fault that could potentially compromise the system's ability to function correctly during an emergency. It is not a supervisory signal, which relates to the status of a separate, monitored system (e.g., a sprinkler valve), nor is it an alarm signal indicating a fire.

An S-95 holder observes a supervisory signal on the FACP indicating 'Fire Pump Power Off'. Which of the following best describes the situation?

Answer: A component critical to the building's fire suppression system is in an abnormal state.

A supervisory signal indicates an issue with a system or equipment that the fire alarm panel monitors, rather than a fault in the fire alarm system itself. A 'Fire Pump Power Off' condition means the fire pump, a key part of the sprinkler suppression system, has lost power and is in an off-normal state that requires attention. Low batteries or wiring faults in the FACP would generate a trouble signal.

Which of the following conditions would initiate a supervisory signal, but NOT a trouble signal?

Answer: A tamper switch on a sprinkler control valve being closed.

A supervisory signal is generated when a monitored system changes to an abnormal state. A closed tamper switch indicates that a sprinkler control valve is not in its normal open position, which impairs the suppression system. The other options—loss of AC power, an open NAC circuit, and communication failure—are all faults within the fire alarm system itself and would generate a trouble signal.

While on duty, an S-95 certificate holder notices the FACP is beeping with a yellow light illuminated. The display reads 'Low Air Pressure - Dry Sprinkler System Zone 3'. What is the correct signal classification and the immediate priority?

Answer: Supervisory signal; the certificate holder should investigate and notify the building manager.

Low air pressure in a dry sprinkler system is an 'off-normal' condition for a monitored piece of fire protection equipment. This generates a supervisory signal. It is not a trouble signal, which would indicate a fault with the FACP or its wiring. The immediate action is to investigate and inform the appropriate personnel, as it indicates a potential impairment to the fire suppression system, but not an active fire. The FDNY is not typically dispatched for supervisory signals.

A fire alarm control panel is operating on its secondary power source (batteries) due to a building-wide power outage. After several hours, a distinct, audible signal begins to sound from the FACP, and the display shows 'Low Battery'. This signal is classified as a:

Answer: Trouble Signal

A 'Low Battery' condition indicates a fault with a critical component of the fire alarm system itself—its secondary power supply. According to NFPA 72, faults within the fire alarm system, including its power supplies, wiring, and components, are annunciated as trouble signals. This alerts personnel to a condition that could prevent the system from operating as intended in an emergency.

What is the fundamental purpose of a supervisory signal within a fire alarm system?

Answer: To monitor the status of other fire protection systems and indicate when they are in an abnormal state.

The core function of a supervisory signal is to indicate that a separate but related fire protection system being monitored by the FACP is in an off-normal or compromised state. Examples include a closed sprinkler valve, fire pump power loss, or low pressure in a dry pipe system. This is distinct from a trouble signal, which points to a fault within the fire alarm system itself.