Room Air Changes Per Hour

The number of air changes per hour that will occur in the space being ventilated. The concept of an air change does not imply that a complete change of all air in the space will occur. The percentage of air in the space which is exchanged depends on the airflow within the space, which will be influenced by the distribution and locations of the incoming and exiting air.

Formula

  • \( N_{changes} = \frac {60Q}{V_{room}} \)
Variable Units Description
Q Flow Rate:: Cubic Foot Per Minute Volume flowrate of dilution
v Volume: Cubic Foot The volume of the space being ventilated

Room Air Changes Per Hour

\( N_{changes} = \frac {60Q}{V_{room}} \)
Nchanges
=
60 *
Q
/
Vroom

Digits of Precision:

CFM
ft3