Large Eddy Simulation of Air Escape through a Hospital Isolation Room Single Hinged Doorway—Validation by Using Tracer Gases and Simulated Smoke Videos

Saarinen, Pekka E.; Kalliomäki, Petri; Tang, Julian W.; Koskela, Hannu

A very large air flow rate without creating a draughty environment can be attained by using downward ventilation with large supply area [24] . Guidelines for isolation rooms do not recommend any particular ventilation strategy, but require keeping the room at negative pressure differential [40] . Kim and Augenbroe [41] suggest satisfying this by adaptive VAV (Variable Air Volume) operation, normally maintaining a low negative pressure differential, but temporarily inducing a higher value prior to door operation, to reduce energy consumption. As demonstrated by Adams et al [42] , containment failure during door operation and passage can be significantly reduced by applying pressure difference. Even though the pressure differential immediately disappears when the door is opened, the supply and exhaust air flow differential, used to generate the underpressure in the isolation room, remains and works against the flow escaping from the isolation room.