Air-change effectiveness

Air-change effectiveness

The ability of an air-distribution system to provide outside air where occupants breathe. It is defined as the age of air that would occur throughout the space if the air was perfectly mixed, divided by the average age of air where occupants breathe.
References in periodicals archive ?
The accuracy in CRE (absolute values) is presented in Figure 9, which are comparable to the uncertainty estimated by ASHRAE Standard 129-1997 on measuring air-change effectiveness in field-based measurements of [+ or -]0.
In practice, two indices of ventilation effectiveness are air-change effectiveness (ACE) and pollutant removal effectiveness (PRE).
In ASHRAE Standard 129 (ASHRAE 2002), the air-change effectiveness, designated with E, is defined and is twice the air exchange effectiveness, i.