Section C408.1/Commissioning
IECC C408 requires commissioning of mechanical and lighting systems to verify installed performance matches design documents.
Mechanical systems with a total heating capacity over 480,000 Btu/h or cooling capacity over 480,000 Btu/h and lighting control systems must be commissioned before occupancy. Commissioning includes preparation of a commissioning plan, functional performance testing of each system, verification that systems operate per the sequences of operation, and a commissioning report documenting the results. The commissioning must verify that: heating and cooling equipment operates at the specified efficiency, economizers function per the control sequence, lighting controls (occupancy sensors, daylight sensors) activate correctly, and air and water balancing meets design specifications.
Why this section exists
Studies consistently show that 30-50% of commercial buildings have HVAC and lighting controls that do not function as designed at the time of occupancy. Sensors are wired incorrectly, economizer dampers are stuck, occupancy sensors have wrong timeout settings, and VAV boxes are not calibrated. These deficiencies waste 10-30% of building energy. Commissioning catches these issues before occupancy, ensuring that the energy-saving features specified by the designer actually function as intended.
What plan reviewers look for
Plan reviewers check the specifications for a commissioning plan and functional testing requirements. They verify the commissioning scope includes all required systems (HVAC above the capacity threshold, lighting controls). They check that the specification requires a commissioning report and corrective action for deficiencies. They verify the specifications identify who performs the commissioning (typically a third-party commissioning agent for larger projects).