Testing air permeability in isolation rooms

Blanca Beato-Arribas, the Asset Performance Team leader at BSRIA, the ISO 9001-registered test, instruments, research, and consultancy organisation, describes her recent work testing the design of isolation rooms that allow the room to be optimally used for both infectious and immunocompromised patients. With pressure differentials the determining factor when controlling infection between an isolation suite and the rest of the hospital, she explains that air permeability levels within the suite should be as low as possible.

The design of isolation rooms intended for the prevention of airborne transmitted diseases is typically dependent on the category level of the pathogens they aim to contain, and whether the patient is infectious or at risk of infection. Isolation suites designed to protect against airborne infections for pathogens in categories 1 to 3 may consist of several adjoining spaces, e.g. an entrance lobby, patient’s room, and en suite bathroom. The ventilation strategies used to protect against infection transmission of airborne pathogens can be divided into two groups – those used to prevent transmission between the suite and the rest of the hospital, and those used within the isolation suite itself. The latter include dilution ventilation (where the concentration of a pathogen is diluted, reducing the likelihood of a person being exposed to an infectious dose), and good mixing, (where the concentration of a pathogen is diluted to the same level everywhere in a room, avoiding stagnant areas of high contaminant concentration in the room). 

Pressure differentials