The present study analyzed air flow distribution in general hospitals of respiratory diseases to identify the air-conditioning that has low probability of secondary air infections owing to absence of air flow. The medical care department and the lobby space used the measurement values of the T?air flow, while the medical care department and the ward department conducted a field measurement using the actual measurement values as the input condition.
First, we analyzed the airflow distribution using the STAR-CCM+ software, a numerical calculation program, for the general hospitals. As a result, airflow mixing was expected to occur due to the presence of airflow in the medical care department and the lobby space, which is a commonly used intersection by hospital visitors with respiratory diseases and/or non-infectious diseases . Therefore, we proposed five improvement methods and analyzed the airflow distribution by changing the positions of the supply and return diffuser at the boundary between the medical care department and the lobby space. As the improvement method of installing the supply diffuser at the first and third rows and the return diffuser at the second row did not lead to the occurrence of airflow mixing, it was judged that the probability of secondary airborne infections in the hospital is also low.
Second, as a result of analyzing the air flow distribution of the ward department, airflow mixing was expected to occur in the room, hallway, and rest area, where hospitalized patients with respiratory diseases, hospital visitors, and medical staffs come into contact. Therefore, the distribution of airflow was analyzed by suggesting three improvement methods: zoning change, relocation of rooms, and installation of bi-directional compartment door. The results of the analysis indicated that the probability of secondary airborne infections in the hospital would be also low, as the improvement method of rearranging the rooms and installing the bi-directional compartment door between the room and the rest area did not lead to the occurrence of airflow mixing.
Thus, the improvement methods of setting up supply diffuser at the first and third rows and the return diffuser at the second row in the medical care department and the lobby space, and of rearranging rooms in the ward department and installing the bi-directional compartment door between the room and the rest area are the optimized air-conditioning conditions with a low probability of secondary airborne infections in hospitals.