Fault detection and diagnostics (FDD) in BAS refers to what?

• A. Manual inspection of equipment by technicians.
• B. Encryption of sensor data for security.
• C. Scheduling maintenance windows.
• D. Automated methods to identify equipment faults or performance degradation from sensor/actuator data.

Answer: (D)

Fault detection and diagnostics in building automation focuses on automated methods to identify equipment faults or performance degradation from sensor and actuator data. Rather than relying on manual inspections, FDD continuously analyzes readings from motors, fans, pumps, valves, temperatures, pressures, and other signals, compares them to expected behavior or models, and flags anomalies. When a fault or drift is detected, the system often provides diagnostics that point to likely causes and suggests corrective actions, helping maintain comfort, reliability, and energy efficiency. This approach uses data-driven techniques, rule-based alerts, or machine learning to catch issues early, even between routine maintenance visits. The other options miss the core idea: manual checks are not automated, encryption concerns security rather than fault detection, and scheduling relates to timing rather than detecting operational problems.