Commissioning Procedures

What Is Commissioning?

Commissioning (Cx) is a systematic process of verifying that all building HVAC systems perform according to the owner's requirements and the design intent. It is not simply testing equipment to see if it "turns on" - it is a comprehensive verification that every component, every control sequence, and every operating mode functions as designed.

ASHRAE Guideline 0 defines commissioning as "a quality-focused process for enhancing the delivery of a project. The process focuses upon verifying and documenting that all of the facility systems are planned, designed, installed, tested, operated, and maintained to meet the owner's project requirements."

For NCI commercial system performance specialists, commissioning knowledge is essential because:

• It provides the framework for systematic performance testing
• It defines the benchmarks against which system performance is measured
• It creates the documentation that supports ongoing performance management
• It is increasingly required by building codes, LEED certification, and owner specifications

Types of Commissioning

New construction commissioning: Verifying that newly installed HVAC systems meet the design specifications before the building is occupied. This is the most common type and is required by many building codes for commercial buildings.

Retro-commissioning (RCx): Applying the commissioning process to existing buildings that were never properly commissioned. This is what NCI performance specialists most frequently perform - testing existing systems against their original design intent (or an updated performance benchmark if design data is unavailable).

Re-commissioning: Repeating the commissioning process on a building that was previously commissioned but has drifted from its performance baseline over time. Recommended every 3-5 years.

Ongoing commissioning (OCx) / Monitoring-based commissioning (MBCx): Continuous monitoring of system performance using building automation system data to detect performance degradation in real time.

Pre-Functional Checklists

Pre-functional testing verifies that equipment is properly installed and ready for functional testing. Think of it as verifying the physical infrastructure before testing the performance.

Air Handler Pre-Functional Checklist:

• Verify unit is level and properly supported
• Check all electrical connections and verify proper voltage at the disconnect
• Inspect fan wheel for damage, check rotation direction
• Verify belt tension and alignment (belt-drive fans)
• Inspect filter rack and verify correct filter size and type installed
• Check coil condition (clean, fins straight, no damage)
• Verify condensate drain is properly connected and trapped
• Check all access panels are secured
• Verify ductwork connections are sealed at the unit
• Confirm vibration isolation is in place

VAV Box Pre-Functional Checklist:

• Verify box is properly supported and accessible
• Check that the inlet duct is properly connected and sealed
• Verify actuator is mounted and linkage is connected
• Check that the controller has power and communication
• Verify the thermostat is installed in the correct zone
• Inspect reheat coil connections (hot water piping or electrical)
• Verify downstream ductwork is connected and sealed

Duct System Pre-Functional Checklist:

• Walk the entire duct system and inspect for disconnected sections
• Verify all joints are sealed with mastic or approved sealant
• Check duct supports and verify proper spacing
• Verify fire dampers are installed at rated penetrations
• Check that all manual dampers are accessible and labeled
• Verify insulation is continuous with no gaps

Commissioning is a systematic verification that HVAC systems perform as designed, not just that they turn on. Pre-functional testing verifies physical installation before functional testing begins. Studies show 50% or more of new commercial buildings have HVAC deficiencies that would be caught by proper commissioning but go undetected without it.