Testing of a downflow system for high risk infectious disease isolation rooms

Isolation room airflows for infectious diseases are designed to minimise the risk of transmission of airborne pathogens to those outside the room and to protect healthcare workers who tend to the patient. This study considers the risk in the vicinity of the patient and conducts an experimental investigation into a downflow ventilation design to evaluate whether it is capable of providing protection to a healthcare worker. Anemometry and smoke tests are conducted in a mock up room to assess influence of ventilation rate, extract design, heat loads and flow local to a healthcare worker. Results show a good downward flow can be established, but a fan speed capable of delivering 0.35m/s and central extract are required to create a uniform flow. Heat loads and a healthcare worker leaning over the bed both compromise downflow effectiveness; local flow acceleration and exhaust can mitigate to some extent.