UNVEILING THE IMPACT OF AIR CHANGE RATES ON PARTICLE DISPERSION IN PATIENT WARDS

The purpose of this study is to examine the effect of air change rate (ACH) on reducing particle concentration in a patient ward using numerical simulation. A patient ward is a large room or space in a medical facility where individuals with similar health conditions or treatments are grouped. It is equipped with modern beds, medical care systems, lighting, and ventilation systems to maintain a high level of hygiene. Airborne transmission in patient wards can easily spread to other individuals. Therefore, the ACH in the patient ward needs to be increased. Three ACH cases were investigated along with a baseline case using a simplified CFD model. The patient ward model was constructed and validated based on past literature. The Renormalization Group (RNG) k-epsilon turbulence model was selected to simulate airflow velocity in the patient ward. The movement of airborne particles was simulated using the Discrete Phase Model (DPM). An effective ACH was determined from the three cases. Based on the results, the most effective ACH in reducing particle dispersion in the patient ward was identified. The findings indicate that in Case 3, where ACH = 25h-1 and the ventilation opening size was 1 m × 1 m, the high airflow velocity in the patient ward completely reduced airborne particle concentration (100%) above patient 1 and 100% around other patients and medical staff. By reducing particle concentration, the number of particles that could infect other patients was also significantly reduced.