Maintenance and Commissioning
Maintenance strategy
Reactive (run-to-failure) maintenance is cheap to administer and expensive in downtime; preventive maintenance is calendar-based; predictive (condition-based) maintenance uses vibration analysis, oil analysis, infrared thermography, and ultrasonic leak detection to intervene just before failure. Reliability-centered maintenance prioritizes tasks by failure consequence using FMEA and MTBF data. In energy terms, deferred maintenance appears as fouled coils, leaking valves, slipped belts, and stuck dampers, each silently raising kW/ton or fan power.
Commissioning versus retrocommissioning
Commissioning is a quality process, not a repair. It begins with the owner's project requirements and the basis of design, proceeds through functional performance testing, and closes with seasonal verification, training, and a systems manual. ASHRAE Guideline 0 and Standard 202 define the process, and 90.1 requires commissioning for new commercial construction above a size threshold. Existing-building commissioning targets low-cost operational fixes and typically yields 5 to 15% whole-building savings. Monitoring-based commissioning sustains those savings through continuous trend review and fault detection.
Traps
Questions blur commissioning with testing, adjusting, and balancing (TAB is only one input), or assert that commissioning guarantees energy savings (it verifies design intent). The commissioning authority should be independent of the design and construction team, and savings from retrocommissioning decay within a few years without persistence measures.
Rule of thumb
Budget new-building commissioning at roughly 0.5 to 2% of construction cost.