[AIVC, Air infiltration and ventilation glossary, 1992]:equation describing the airflow rate through a building (or component) in response to the pressure difference across the building (or component). This equation takes the form of Q = C ΔPn; Where C is the flow Coefficient, ΔP is the change in pressure over the component or envelope, and n is the flow exponent. Q represents the resulting volume flow rate expressed in m3/h.(see flow Coefficient, flow exponent)