Commissioning is the process of verifying that installed systems perform as designed. For air handling units, proper commissioning makes the difference between a system that works and one that wastes energy while failing to maintain conditions.
Why Commissioning Matters
Design Intent vs Reality
Design calculations assume specific operating conditions. Reality differs – ductwork resistance varies from predictions, room loads differ from estimates, control sequences need tuning. Commissioning bridges the gap.
Avoiding Problems
Issues identified during commissioning are cheap to fix. The same problems discovered months later are expensive and disruptive. Commissioning catches problems early.
Energy Performance
Poorly commissioned systems waste energy. Fans running faster than necessary, simultaneous heating and cooling, inadequate control – all result from skipped or rushed commissioning.
Documentation
Commissioning records demonstrate achieved performance. They provide baselines for future comparison and evidence for compliance verification.
Commissioning Activities
Pre-Commissioning Checks
Before starting equipment:
- Verify installation matches design
- Check electrical connections are correct
- Confirm controls are wired properly
- Ensure filters are installed
- Clear ductwork of debris
- Verify fire dampers are functional
Initial Start-up
First operation under controlled conditions:
- Confirm fan rotation direction
- Check for unusual noise or vibration
- Verify basic operation of dampers and valves
- Confirm control system communication
Air Balancing
Adjusting airflows to match design requirements:
- Measure airflows at terminals
- Adjust dampers and regulators
- Verify outdoor air rates
- Check pressure relationships between zones
- Document final settings
Controls Commissioning
Verifying control systems operate correctly:
- Test all control sequences
- Tune PID loops for stable operation
- Verify setpoints and schedules
- Test safety functions
- Check BMS integration
Performance Verification
Confirming overall system performance:
- Verify temperatures are maintained
- Check humidity control (where applicable)
- Confirm ventilation rates meet requirements
- Test heat recovery performance
- Measure energy consumption
Common Commissioning Problems
Insufficient Time Allowed
Commissioning takes time. Compressed programmes often squeeze commissioning, resulting in incomplete work.
Missing Information
Commissioning needs design data for comparison. Missing or incorrect design information prevents proper verification.
Access Problems
Commissioning requires access to terminals, plant, and controls. Fit-out progress can obstruct access when commissioning should occur.
Incomplete Installation
Commissioning cannot progress until installation is complete. Outstanding works delay and complicate commissioning.
Control Problems
Many commissioning delays relate to controls. Control system commissioning often takes longer than anticipated.
Roles and Responsibilities
Manufacturer’s Commissioning
Equipment manufacturers commission their products – setting up controls, verifying operation, addressing equipment issues.
Specialist Commissioning
Independent commissioning specialists balance air systems, tune controls, and verify overall performance.
Witnessing
Client representatives or consultants may witness commissioning, verifying it’s completed properly.
Clarity about who does what prevents gaps and duplication.
Seasonal Commissioning
Full commissioning requires operating in all seasons – heating mode, cooling mode, and transitional conditions. Initial commissioning covers the current season; return visits complete other modes.
Building operators should understand which modes remain to be commissioned and report any problems as seasons change.
Documentation
Commissioning produces documentation:
- Commissioning records for each system
- Air balance reports
- Control setpoints and schedules
- Test certificates
- Outstanding items (snagging) lists
This documentation should be included in the building operation and maintenance manual.
Our Commissioning Support
i-Flow supports commissioning of our equipment. We can attend site for manufacturer’s commissioning and provide technical support to commissioning specialists. Contact us if you have commissioning queries.
