ABSTRACT
A typical ventilation system is essentially made up of fans and ducts to supply clean air to interior spaces, and other fans and ducts to exhaust stale or contaminated air to the outdoors. Ideally, at a given ventilation rate air flows through interior spaces, where it provides thermal comfort, dilutes contaminants and supplies fresh air for occupant use. The success or failure of the ventilation system rests with a number of interdependent components and principles, including airflow, use of return air in supply air, demand control, air balancing, air distribution and filtration. The Indoor Air Quality Procedure, however, involves measuring varying levels of multiple contaminants—if there are no problems, the overall ventilation rate is assumed to be acceptable, and need not be increased. True, good ventilation or proper ventilation rates are instrumental to ensuring a good supply of indoor air, but it does not necessarily follow that acceptable indoor air quality is always traceable to ventilation systems.
