When construction activities create airborne contaminants, a portable HEPA air scrubber is crucial for reducing particle levels in anterooms and protecting sensitive hospital environments.
Particle diffusion occurs when airborne particles move from an area of higher concentration to an area of lower concentration. Within an Infection Control Risk Assessment (ICRA) containment system, construction activities generate a high concentration of airborne particles in the containment room. A
study published in Science Direct found that particulate matter (PM) concentrations during certain construction activities can be 100 to 1,000 times higher than background levels, highlighting the significant increase in airborne particles due to construction processes. Each time the door between this room and the adjacent anteroom opens, these particles—including construction dust, microbial contaminants, and other bioaerosols—can migrate into the anteroom.
These particles are often microscopic and pose significant health risks to immunocompromised patients, as well as indirect risks to sterile equipment and sensitive environments. Therefore, the use of portable HEPA-filtered recirculating units inside the anteroom is essential. These units continuously remove small particles from the air, providing high air exchange rates that rapidly reduce particle concentrations before the anteroom door is opened into the healthcare facility.
The effectiveness of these portable HEPA filter units depends on their filtration efficiency and airflow exchange rate. Recirculating the HEPA-filtered air within the anteroom allows the air to be continuously pulled from the room, filtered through a HEPA unit, and then returned to the same space instead of being vented outside, continuously reducing the number of particulates in the anteroom. The filter efficiency of a portable HEPA filter unit—often rated according to the
MERV rating system—is a measure of how effectively the filter removes airborne particles in sizes from 0.3 microns (µm) to 10.0 µm in diameter from the air as it passes through the HEPA filter.
Higher air changes per hour, combined with true HEPA filtration (99.97% efficiency at 0.3 microns), enables faster capture and removal of airborne particles. To maximize patient protection, workers are typically advised to pause inside the anteroom for 2 to 3 minutes before opening the door to the clean area, sometimes for more extended periods during heavy demolition work. Wait times are based on the number of air exchanges required and the size of the blower in cubic feet per minute (CFM). This dwell time allows the HEPA unit to significantly reduce particle levels in the anteroom, minimizing the potential for particle migration.
Setting up and maintaining portable HEPA air scrubbers correctly is essential to ensure they work effectively in reducing airborne particle levels in anterooms. Always position the HEPA air scrubber inside the anteroom where it can recirculate the air without obstructing movement or equipment. Make sure all seals are tight, and check for any leaks that could allow unfiltered air to escape. Routine maintenance, including inspecting and replacing HEPA filters as needed, helps the unit maintain its high efficiency throughout the duration of the project.
Once the concentration of anteroom particles is lowered, the risk of particles diffusing outward or being carried by airflow into the clean environment into a sensitive area of a healthcare facility is significantly reduced.
In summary, portable HEPA air scrubbers and filtration systems—used to establish negative pressure and provide highly filtered recirculating airflow—play a critical role in maintaining clean, safe environments during healthcare construction. They help safeguard patients, staff, critical areas, equipment, and supplies, ensuring protection and compliance throughout renovation or demolition activities.
Higgins and Associates, LLC specializes in assisting healthcare clients with the design, testing, and monitoring of Infection Control Risk Assessment (ICRA) healthcare construction containment systems. We offer
online courses that teach the scientific principles of healthcare containment design. Additionally, we have expert consultants in environmental infection control who can assist clients with challenging containment system design issues in sensitive areas of hospitals and other healthcare facilities.
