OPTIMUM INDOOR AIR UV GERMICIDAL IRRADIATION SYSTEM FOR APPLICATION IN COMMUNITY HOSPITALS

This research investigated the optimum design and operation of an ultraviolet germicidal irradiation (UVGI) system for a tuberculosis (TB) isolation room modified from a patient’s room of the type found in community hospitals in Thailand. The goal was to obtain the maximum germicidal irradiation effectiveness while still keeping safety standards for the occupants and staff. The study was carried out in an actual size replicated patient’s room with different positions for the air inlet and outlet openings to allow 3 different ventilation patterns. The air change rates tested were 6, 9, and 12 air changes per hour (ACH). Furthermore, the relevant factors that were studied for the irradiation using UV light were the tube power, the installation height, the number of tubes, and the installation pattern. The air velocity and the distribution of the UV intensity in the replicated room were measured. The fluid dynamics model, ANSYS Fluent, was used to simulate the flow path of the disease particles and the time that they spent in the upper zone of the room where the irradiation occurred. Results showed that that the best germicidal irradiation efficiency could be obtained with 4-sided installation of 16W UV tubes at a height of 3.3 m.\ above the floor, with an in-low/out-high ventilation pattern and 6 ACH ventilation rate. This optimum system design could achieve 98.19% efficiency, which was 16% better than the standard design. The findings of this study can be beneficial for both the improvement of the care of TB disease patients and contamination prevention in Thai community hospitals.

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