Seasonal commissioning and fine-tuning

How does Seasonal commissioning and fine-tuning work, step by step?

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   Step 1: Write the return visits into the contract

   The obligation is stated in the tender documents: how many visits, roughly when, what will be tested, who attends, what records are produced, and what commercial mechanism holds the contractor to it. On most projects a portion of retention or a defined fee stage is tied to the visits being completed and accepted. Naming the seasons rather than fixed dates gives the flexibility to pick genuinely representative weather, but a long stop date is still needed or the visit drifts indefinitely.

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   Step 2: Hand over with the deferred tests listed

   At completion the tests that could not be done are listed explicitly rather than passed over. Typically that covers full heating or full cooling capacity, changeover between modes, frost and summer control strategies, and anything that depends on load the empty building could not produce. Listing them protects everybody: the client knows what has not been proven, the contractor knows what he still owes, and nobody discovers the gap two years later while looking for somebody to blame.

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   Step 3: Monitor performance through the first months of occupation

   Between handover and the return visit the systems are monitored, usually through the trend logging in the building management system. What is wanted is evidence: how the plant actually runs, when it starts and stops, how long it takes to bring the building to condition, whether any zone is fighting itself, and where the complaints are coming from. Energy consumption is tracked against expectation. This data is what makes the return visit productive rather than a walk round in a coat.

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   Step 4: Pick the right conditions and return

   The visit is timed for weather that genuinely loads the system - a cold spell for heating, a warm spell for cooling - and for a period when the building is normally occupied rather than a holiday week. On most projects a few days notice is needed to get the right people back. Attendance normally includes the controls engineer, the mechanical commissioning engineer, the operator's own staff and, where one is appointed, the commissioning authority. The operator's staff attending matters, because much of the value is transferred to them in conversation on the day.

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   Step 5: Run the deferred tests under real load

   The systems that could not be proven are now run and tested against the criteria the designer set and the specification records. Capacity, changeover, sequencing and the response of the controls to genuine demand are all observed rather than simulated. Where a system falls short, the cause is identified before anything is adjusted: undersized plant, a control fault, an installation defect and a wrong setting all look the same on a complaint sheet and have completely different remedies.

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   Step 6: Adjust settings against how the building is actually used

   This is the fine-tuning proper. Occupancy times are corrected to what the building really does. Setpoints and deadbands are reviewed. Optimum start and stop, setback, ventilation rates against actual occupancy, and lighting and blind control are all revisited against the trend data. Small zone-level rebalancing is done where the occupied load has turned out different from the design assumption. Every change is recorded with the reason and the previous value, so a later engineer can see what was done and why, and reverse it if the building changes again.

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   Step 7: Retrain and update the records

   The people running the building have now lived with it for months and will ask better questions than they could at handover. A short retraining session at the return visit is usually worth more than the original one. The controls description, the operating information and the maintenance schedules are updated to reflect the adjusted settings, and the updated versions are issued to the operator. Records that still describe the handover settings are worse than no records at all.

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   Step 8: Report and close out

   The visit produces a report: what was tested, what was found, what was changed, what remains outstanding and what the client should watch. Where the shortfall is a defect rather than a setting, it goes onto the defects list with an owner and a date. Where it is a design assumption that has turned out wrong, that is fed back to the design team, and on repeat clients it is the single most useful thing the exercise produces for the next project.