Source google image: https://www.airepure.com.au/wp-content/uploads/2016/09/Figure-1-Schematic-of-isolation-room-with-terminally-mounted-HEPAs-Pressure-Balanced-200×200.jpg
N power isolation switch
Source google image: https://www.airepure.com.au/wp-content/uploads/2016/09/Figure-1-Schematic-of-isolation-room-with-terminally-mounted-HEPAs-Pressure-Balanced-200×200.jpg