In his October 25th ASHE-sponsored webinar, TJC Director of Engineering George Mills emphasized the importance of maintaining proper pressure relationships for infection prevention where rooms are required to be positive or negative with respect to adjacent rooms or spaces. Mr. Mills reiterated previous statements regarding how TJC surveyors will test for required pressure relationships – surveyors will use the tissue test very early to assess the adequacy of pressure relationships at the doorways of rooms subject to those requirements. The tissue test is often performed by holding a thin tissue at the bottom door gap of a closed door. The tissue will typically bend or flutter in the direction of air flow, which will be from a more positive to a less positive (or from a less negative to a more negative) space. As a rule of thumb, the “more clean” areas need to be positive pressure with respect to the “less clean” areas. If the tissue flutters from the “more clean” areas to the “less clean” areas – no problem. If the tissue flutters in the opposite direction however – big problem. This is likely to result in a Requirement for Improvement (RFI) against Standard EC.02.05.01, Element of Performance (EP) #6, which states the requirements for areas designed to control airborne contaminants along with the concomitant need for appropriate pressure relationships, air-exchange rates, and filtration efficiencies.
