S95 Supervisory and Trouble Signals 3 — Questions and Answers
Question 1: What color is typically used to indicate a TROUBLE signal on a fire alarm control panel?
- Red
- Green
- Yellow or amber (Correct answer)
- Blue
Correct answer: Yellow or amber
Yellow or amber indicators are the industry-standard color for trouble signals on fire alarm control panels, distinguishing them from red alarm signals.
Question 2: A fire pump running signal at the FACP indicates:
- The fire pump has started and may indicate a demand for water (Correct answer)
- A wiring fault in the fire pump circuit
- The fire pump jockey pump has failed
- The main fire pump is shut down for maintenance
Correct answer: The fire pump has started and may indicate a demand for water
A fire pump running signal is a supervisory signal indicating the fire pump has started, which may indicate actual firefighting water demand or an automatic test cycle.
Question 3: Which device monitors the water level in a fire protection storage tank and generates a supervisory signal when the level drops below normal?
- Flow switch
- Tamper switch
- Low water level switch (Correct answer)
- Pressure supervisory switch
Correct answer: Low water level switch
A low water level switch monitors storage tank water levels and sends a supervisory signal when water drops below the minimum required level.
Question 4: According to NFPA 72, a trouble signal audible notification device at the FACP must produce a sound that is:
- Identical to the alarm sound but at lower volume
- A distinctive sound clearly different from alarm signals (Correct answer)
- Continuous tone at 85 dB minimum
- Silent if the panel is in the attended mode
Correct answer: A distinctive sound clearly different from alarm signals
Trouble signal notification must be distinctly different from alarm signals so personnel can immediately differentiate between emergency and maintenance conditions.
Question 5: A cross-zoned detection system requires two separate detection zones to activate before sounding a full alarm. If only one zone activates, the FACP would typically display a:
- Full building evacuation alarm
- Supervisory signal
- Pre-alarm or investigation signal (Correct answer)
- Trouble signal
Correct answer: Pre-alarm or investigation signal
In a cross-zoned system, single-zone activation typically generates a pre-alarm or investigation condition rather than a full alarm until the second zone confirms.
Question 6: Which of the following is classified as a supervisory signal according to NFPA 72?
- An open in the notification appliance circuit wiring
- A smoke detector with reduced sensitivity due to contamination
- A post-indicator valve moved to a partially closed position (Correct answer)
- A power supply failure at the FACP
Correct answer: A post-indicator valve moved to a partially closed position
A post-indicator valve moved from its fully open position generates a supervisory signal because it represents an off-normal condition in the suppression system.
Question 7: The purpose of a 'waterflow retard' on a wet-pipe sprinkler system alarm check valve is to:
- Increase system water pressure during demand
- Delay the alarm signal to reduce false activations from surges (Correct answer)
- Generate a supervisory signal during normal testing
- Monitor the flow switch sensitivity continuously
Correct answer: Delay the alarm signal to reduce false activations from surges
A retard chamber delays the waterflow alarm signal by a few seconds to allow brief pressure surges to pass without triggering a false alarm.
S95 Supervisory and Trouble Signals 3
What color is typically used to indicate a TROUBLE signal on a fire alarm control panel?