[AIVC, Air infiltration and ventilation glossary, 1992]:defined as the total volumetric supply airflow rate per unit volume of the room. Specific flow is expressed by the equation; a= Q/V , where Q is the ventilation air flow rate (m3/s) and V is the total volume of the room (m3). Specific flow is often called the Air Change Rate(NOTE: Specific flow is usually expressed by the letter “n”, but “a” is used here as not to confuse with the flow exponent “n”.)(see also air change rate; air change time; coefficient of air change performance; local air change index; nominal time constant)