Glossary
TAB (Testing, Adjusting, and Balancing)
Plain-Language Definition
The process of measuring and adjusting airflow, water flow, and system performance in HVAC systems to ensure they deliver design conditions to all zones. Performed during commissioning and periodically during building life.
Technical Context
TAB covers air systems (supply, return, exhaust volumes per diffuser), water systems (flow rates through coils, chillers, pumps), and system performance (temperatures, pressures, control response). Governed by ASHRAE Standard 111, NEBB, and AABC procedures. TAB reports document design vs actual performance for every terminal device.
Why It Matters
Without TAB, some zones get too much air/cooling while others get too little. Hot and cold complaints in occupied spaces are often caused by unbalanced systems, not equipment failure. A current TAB report is essential baseline documentation.
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