In a recent project, during a pre-inspection of the job site, a question was raised regarding the shut down of fans during a fire event. In an ICU unit, contained within a single smoke compartment, the isolation fan for the AII rooms must be kept running during the fire event due to health concerns. However, general exhaust fans, contributing just to 30% of the total exhaust in this case, were mandated to shut down when the fire alarm signal is on. I understand the concern regarding more oxygen being pulled into space; however, in presence of smoke in a patient room, where the patient has limited mobility and may be set a 48" AFF, no source of exhaust to move air out of this breathing level doesn't seem to contribute to safety. There is no clear statement in the NFPA 99. Anyone with insights on this topic?