What is FDD?
Fault Detection and Diagnostics (FDD) System is a software platform that utilizes building analytic algorithms to convert data provided by sensors and devices to automatically identify faults in building systems and provide a prioritized list of actionable resolutions to those faults based on prioritized performance impact.
Why FDD?
Energy efficiency of a new building’s HVAC system will degrade over time caused by poorly maintained, failing and improperly controlled equipment. The proposed FDD requirement will reduce that degradation by detecting HVAC system faults and notifying building operators so that corrective actions may be taken to repair the faults and reduce energy consumption of the building. Additionally, FDD systems are being utilized to drive operational efficiency, make better use of maintenance personnel, and resolve comfort issues.
Measure Description
Add FDD requirements for large buildings into CA Title 24, Part 6 to align it with the 2021 version of the International Energy Conservation Code.
Proposed Code Language
120.2(l) Fault Detection and Diagnostics (FDD). Newly constructed buildings that require DDC according to Section 120.2(j) shall include a fault detection and diagnostics (FDD) system to monitor the HVAC system’s performance and automatically identify faults. The FDD system shall:
Utilize permanently installed sensors and devices to monitor the HVAC system’s performance by monitoring central plant equipment, zone terminal equipment, and associated components including but not limited to motors, actuators, valves, and dampers.
Sample the HVAC system’s performance at least once per 15 minutes.
Automatically identify HVAC system faults using algorithmic-based analysis that performs rule-based or model-based diagnostics separately from the monitoring and alarming functionality of the DDC. A list of possible faults that should be identified by the FDD system includes but is not limited to: HVAC systems that improperly simultaneously heat and cool; excessive outdoor air intake and conditioning; under-utilized free cooling potential; equipment malfunction (such as broken/leaking valves, broken/stuck dampers, sensors out of calibration); wrong setpoints and operating schedules; unintentional manual overrides; lack of energy-saving control sequences (such as chilled water reset); a bad bearing in a motor or compressor; misaligned motor, rotor imbalance, or cracked rotor bar; dirty filters or strainers; incorrect refrigerant or oil levels; pumps with throttled discharges; short cycling of equipment; excessive oscillation (hunting) of control points and/or control loop tuning needs; incorrect fan and pump speeds, pressures, or low flow rates; improper building or space pressurizations (negative or positive); inefficient boiler combustion; and excessive building peak electrical demand.
Automatically notify authorized personnel of identified HVAC system faults.
Automatically provide prioritized recommendations for repair of identified faults based on analysis of data collected from the sampling of the HVAC system performance.
Be capable of transmitting the prioritized fault repair recommendations to remotely located authorized personnel.
Be capable of tracking and reporting the history of identified faults and identifying corrective actions from identification of fault through closure.
Exception to Section 120.2(l): R1 and R2 occupancies.
