Abstract

To prevent the spread of infections in healthcare facilities, a personal isolation unit (PIU) can be utilized as an alternative to isolation rooms. The fan filter unit (FFU) mounted in PIU filters air from the PIU and releases it into the patient room. This study aims to propose appropriate operating airflow rates and installation quantities of PIUs based on their removal efficiency under various operational conditions in healthcare facilities, with the goal of establishing application guidelines. To estimate indoor airborne particle concentrations, a multi-zone model was developed. The parameters required for this model were derived from full-scale chamber experiments. The optimal operating airflow and number of PIUs were determined based on the concentrations calculated using the model. The results indicate that higher PIU airflow rates are required in cases of lower air change per hour (ACH) in the patient room and a greater number of infected patients. A comparison of indoor particle concentrations across different room sizes, numbers of infected patients, and numbers of installed PIUs revealed that installing PIUs equivalent to 1/3 of the patient beds are required in order to maintain the same indoor concentration level as that achieved under 6 ACH, with all other conditions being equal.