[AIVC, Air infiltration and ventilation glossary, 1992]:the rate at which outside air is intentionally supplied to a building or zone. Sometimes ventilation is used to describe the total mechanical air change in a room or building. This rate may then frequently comprise a considerable proportion of recirculated rather than outdoor air. Hence when apparently very large ventilation rates are quoted, it is important to establish the proportion of flow representing outside supply air. The remainder will be recirculated air.[ASHRAE 62.2]:a mechanical exhaust system, supply system, or combination thereof shall be installed to operate for each dwelling unit to provide continuous whole-building ventilation with outdoor air at a rate not less than specified in Section 4.1.1.[EN 16798-1:2019, 3.26]:magnitude of outdoor air flow to a room or building through the ventilation system or device.[ISO 16814:2008, 3.45]:airflow rate at which outdoor air enters a building or enclosed space.