IAQ is a subcategory to which division?

• A. HVAC
• B. TAB
• C. Building
• D. Electrical

Answer: (B)

Indoor Air Quality hinges on how a building’s ventilation and HVAC system are tested, adjusted, and balanced to meet design conditions. The Testing, Adjusting, and Balancing (TAB) discipline is the part of the trade that verifies airflow, pressure relationships, and system performance, all of which directly affect IAQ by ensuring proper ventilation rates, filtration effectiveness, and contaminant control. In this framework, IAQ is treated as a subcategory of TAB because improving air quality depends on the precise measurement and tuning of the system that TAB provides. The HVAC division is broader, covering design and operation of heating and cooling equipment, while Building and Electrical address other, less directly related areas.