CML Security Systems Installation & Maintenance 4 — Questions and Answers
Question 1: What is the purpose of a 'shunt' function in an alarm zone?
- Increase sensor sensitivity
- Temporarily bypass a zone without affecting the rest of the system (Correct answer)
- Reset the control panel after an alarm
- Add a second sensor to the zone
Correct answer: Temporarily bypass a zone without affecting the rest of the system
Shunting bypasses a specific zone — for example, allowing a loading dock door to remain open during deliveries — without disarming the entire system.
Question 2: A fingerprint biometric reader requires enrollment before use. Enrollment involves:
- Scanning the fingerprint multiple times to build a reference template stored in the system (Correct answer)
- Entering a PIN to link the reader to the panel
- Replacing the factory firmware
- Setting the sensitivity threshold remotely
Correct answer: Scanning the fingerprint multiple times to build a reference template stored in the system
Enrollment captures multiple scans of a fingerprint to create an averaged template that the reader uses for future identification comparisons.
Question 3: Which type of camera lens provides the widest field of view for covering large open areas?
- Telephoto (75mm)
- Standard (25mm)
- Wide-angle (2.8mm) (Correct answer)
- Pinhole (1.2mm)
Correct answer: Wide-angle (2.8mm)
A wide-angle lens with a short focal length (e.g., 2.8mm) provides a broad field of view, ideal for large rooms, parking lots, or lobbies.
Question 4: An alarm panel's backup battery is required to power the system for how long in the absence of AC power under UL 681 standards?
- 4 hours
- 8 hours
- 24 hours (Correct answer)
- 72 hours
Correct answer: 24 hours
UL 681 and most NFPA standards require residential and commercial alarm systems to maintain full operation for a minimum of 24 hours on backup battery alone.
Question 5: When installing conduit for alarm wiring through a fire-rated wall, the installer must:
- Use PVC conduit only
- Seal the conduit penetration with listed fire-stop material (Correct answer)
- Install a smoke detector inside the conduit
- Apply shielded cable only through fire walls
Correct answer: Seal the conduit penetration with listed fire-stop material
Any penetration of a fire-rated assembly must be sealed with UL-listed fire-stop material to maintain the wall's fire rating and prevent fire spread through the conduit.
Question 6: A CCTV DVR is set to continuous recording at 30fps for 16 cameras. To extend storage retention from 7 days to 14 days without adding cameras, the best adjustment is:
- Increase resolution on all cameras
- Reduce frame rate to 15fps or enable motion-triggered recording (Correct answer)
- Add a second DVR unit
- Compress video using a less efficient codec
Correct answer: Reduce frame rate to 15fps or enable motion-triggered recording
Halving the frame rate or switching to motion-only recording approximately doubles storage retention without additional hardware cost.
Question 7: What is the correct procedure when a fire alarm system requires a bypass (impairment) for maintenance?
- Simply disconnect the affected zone and resume work
- Notify the authority having jurisdiction (AHJ), central station, and building management; implement a fire watch (Correct answer)
- Arm the remaining zones at double sensitivity
- Wait until after business hours to begin maintenance
Correct answer: Notify the authority having jurisdiction (AHJ), central station, and building management; implement a fire watch
NFPA 72 requires notification to the AHJ, monitoring service, and building management plus implementation of a fire watch whenever a portion of the fire alarm system is out of service.
CML Security Systems Installation & Maintenance 4
What is the purpose of a 'shunt' function in an alarm zone?