Optimizing Biological Indicator Placement for Validating High-Efficiency Particulate Air Housing Decontamination.

Background: The validation of high-efficiency particulate air (HEPA) housing decontamination efficacy is crucial for maintaining critical environments and is normally assessed by positioning biological indicators at the downstream port (filtered side) before the decontamination cycle. This method is favored for its significantly lower biohazard risk. HEPA housings and filters typically designed for high airflow face challenges during decontamination due to the diameters and positions of upstream and downstream ports, potentially impacting the distribution of decontamination agents.

Objective: This study investigates the effectiveness of this prevalent validation method, particularly focusing on the uniformity of decontamination agent dispersion across the HEPA filter.

Methods: Preparation: HEPA filters and housings were set up in a controlled environment. Placement of Biological Indicators: Indicators were positioned at multiple points, including the downstream port and various peripheral regions of the filter. Decontamination Cycle: The decontamination process was initiated using a standard protocol for hydrogen peroxide vapor or another selected agent. Measurement: The concentration of decontamination agents was measured at each indicator position using appropriate detection techniques. Analysis: Data were analyzed to assess the uniformity of decontamination agent distribution and identify any significant variations across different areas of the filter.

Results: Our findings reveal a notable variability in the concentration of decontamination agents across different areas of the HEPA filter, especially in peripheral regions. Such variability poses questions about the current method's ability to ensure comprehensive decontamination, given that the concentration at the exit port does not accurately reflect exposure across all filter surfaces. This discrepancy between expected and actual decontamination efficacy underscores the need for optimization in decontamination practices.

Conclusion: The discrepancy between expected and actual decontamination efficacy underscores the need for optimization in decontamination practices. This study highlights the importance of validating decontamination methods and sets the stage for future research aimed at enhancing the uniformity of agent exposure across the HEPA filter. This study advocates for further investigation into methods that could ensure more reliable and effective decontamination, which is vital for biorisk management and the prevention of pathogen contamination.