States that ANSI/ASHRAE 62-89, Ventilation for Acceptable Indoor Air Quality (ASHRAE 1989), provides guidelines for achieving acceptable indoor air quality in occupied spaces by either of two methods - a Ventilation Rate Procedure and an Indoor Air Quality Procedure. The Ventilation Rate Procedure prescribes ventilation rates assumed to provide adequate indoor air quality when 100% outdoor air is used. This 100% outdoor air value is also the minimum supply airflow per person. The amount of outdoor air in this minimum supply airflow may be reduced below 100% by recirculating adequately cleaned return air if the Indoor Air Quality Procedure is used. States the IAQ Procedure does not set outdoor air ventilation rates but employs both qualitative and subjective air quality evaluation. Uses mathematical analysis to help implement the IAQ Procedure by determining what filter efficiencies are needed (particulate and gas) to account for source capture efficiency, reduced outdoor airflow and poor ventilation effectiveness, all under VAV conditions.

KEYWORDS: Ventilation, indoor, air quality, standards, USA, calculating, air filters, air cleaning, outdoor air, air supply