TAB (Testing, Adjusting and Balancing)

TAB is performed after HVAC installation and before occupancy, as part of commissioning. It covers: air-side balancing (supply, return, exhaust air volumes at each diffuser/grille measured with anemometer or balometer, adjusted using dampers to match design CFM/L/s), water-side balancing (flow rates through coils, chillers, pumps measured and adjusted using balancing valves), and system performance verification (entering/leaving temperatures, pressure drops, fan/pump speeds). Standards: ASHRAE 111 (Practices for Measurement, Testing, Adjusting and Balancing of Building HVAC Systems), NEBB (National Environmental Balancing Bureau) procedures, AABC (Associated Air Balance Council) standards. A TAB report should document design values, measured values, and final adjusted values for every terminal device.

An unbalanced HVAC system results in some zones being too hot while others are too cold, excessive energy consumption, and occupant complaints. TAB ensures the system delivers the designed conditions uniformly. For due diligence, an up-to-date TAB report (within 3-5 years) indicates the HVAC system has been professionally maintained.