To control the source of pollution and its spread, to maintain different air pressures between adjacent areas (forming directional airflow), to keep airflow control (controlling both internal airflow distribution and direction, and requiring prompt capture of pollutants) as well as to control the temperature and humidity (reducing the amount of harmful pathogens generated to patients and providing protection to medical personnel), to establish effective ventilation system (allowing outward flow of supply air first and to produce greater dilution effect) and drainage (removing the contaminated air).

The balanced pressure distribution guarantees an organized flow of directional airflow from the other area of hospital to the room.