Using a HEPA-Filtered Air Scrubber to Control Particle Diffusion
Apr 14
When construction activities create airborne contaminants, a portable HEPA air scrubber is crucial for reducing particle levels in anterooms and protecting sensitive hospital environments.
What Is a HEPA Air Scrubber with Filters?
A HEPA air scrubber with filters is a portable air filtration unit used to remove airborne contaminants in controlled environments such as healthcare construction zones, containment areas, and anterooms. These systems use High-Efficiency Particulate Air (HEPA) filtration to capture fine particles that contribute to contamination risks.
In practice, the unit continuously pulls in contaminated air, passes it through a series of filters, and returns cleaned air back into the same space. This recirculation process is critical in containment setups where exhausting air outside is not always feasible or sufficient.
In an Infection Control Risk Assessment (ICRA) containment system, HEPA air scrubbers are commonly positioned within the anteroom or work area to reduce airborne particle concentrations before air moves into adjacent spaces. By continuously filtering the air, they help limit particle migration during door openings, personnel movement, and active construction.
Most units rely on a layered filtration approach that includes:
This multi-stage design allows the unit to maintain airflow while capturing a wide range of particle sizes, making it suitable for high-risk environments where airborne contamination must be actively controlled.
In practice, the unit continuously pulls in contaminated air, passes it through a series of filters, and returns cleaned air back into the same space. This recirculation process is critical in containment setups where exhausting air outside is not always feasible or sufficient.
In an Infection Control Risk Assessment (ICRA) containment system, HEPA air scrubbers are commonly positioned within the anteroom or work area to reduce airborne particle concentrations before air moves into adjacent spaces. By continuously filtering the air, they help limit particle migration during door openings, personnel movement, and active construction.
Most units rely on a layered filtration approach that includes:
- A pre-filter for larger dust and debris
- A true HEPA filter for fine particulate removal
- An optional carbon filter for odor and gas control
This multi-stage design allows the unit to maintain airflow while capturing a wide range of particle sizes, making it suitable for high-risk environments where airborne contamination must be actively controlled.
Types of Filters Used in HEPA Air Scrubbers
HEPA air scrubbers use multiple filter stages to manage different types and sizes of airborne contaminants. Each filter serves a specific purpose within the system, and overall performance depends on how these layers work together.
Pre-Filter
The pre-filter captures larger particles such as construction dust, fibers, and debris before they reach the primary filtration stage. In healthcare construction environments, this often includes drywall dust, ceiling tile particles, and other coarse materials generated during demolition or renovation.
By removing these larger particles early, the pre-filter helps maintain airflow and prevents premature loading of the HEPA filter.
By removing these larger particles early, the pre-filter helps maintain airflow and prevents premature loading of the HEPA filter.
HEPA Filter
The HEPA filter is the primary filtration component. A true HEPA filter is rated to capture at least 99.97% of particles at 0.3 microns, which includes fine dust, mold spores, and many bacteria-sized particles.
This level of filtration is essential in containment areas where microscopic particles can move between spaces and pose risks to patients, staff, and sensitive equipment. In critical environments, this performance should be verified through proper testing methods such as HEPA air filter blower testing.
It is important to note that HEPA filtration is a distinct standard and not part of the MERV rating system. While pre-filters may use MERV-rated media, the HEPA filter provides the highest level of particulate removal within the unit.
This level of filtration is essential in containment areas where microscopic particles can move between spaces and pose risks to patients, staff, and sensitive equipment. In critical environments, this performance should be verified through proper testing methods such as HEPA air filter blower testing.
It is important to note that HEPA filtration is a distinct standard and not part of the MERV rating system. While pre-filters may use MERV-rated media, the HEPA filter provides the highest level of particulate removal within the unit.
Optional Carbon Filter
Some HEPA air scrubber machines include a carbon filter stage to address odors, volatile organic compounds (VOCs), or chemical off-gassing. This is more common in environments where solvents, adhesives, or other chemical agents are present.
While not always required for basic dust control, carbon filtration can be valuable when odor or chemical exposure is a concern.
While not always required for basic dust control, carbon filtration can be valuable when odor or chemical exposure is a concern.
Why Layered Filtration Is Necessary
Airborne contaminants vary significantly in size and composition. A single filter cannot efficiently capture everything without restricting airflow.
A layered system allows the unit to:
A layered system allows the unit to:
- Capture large and small particles efficiently
- Maintain consistent airflow during operation
- Extend the service life of the HEPA filter
- Provide more reliable performance in high-dust environments
This approach is especially important in healthcare containment, where consistent filtration performance is required throughout the duration of a project.
How an Air Scrubber Reduces Airborne Particles in Healthcare Anterooms
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.
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.
HEPA Air Scrubber Performance: Filtration Efficiency and Air Changes
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 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), enable 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.
Higher air changes per hour, combined with true HEPA filtration (99.97% efficiency at 0.3 microns), enable 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.
Setup and Maintenance Tips for HEPA Air Scrubbers
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.
Why a Portable Air Scrubber is Essential for Infection Control
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.
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.
Key Benefits of Using a HEPA Air Scrubber with Filters
In healthcare construction and other controlled environments, a HEPA air scrubber plays a direct role in reducing airborne contamination, supporting containment strategies, and maintaining safe conditions for both workers and occupants.
When properly selected and positioned, these units provide measurable benefits across safety, compliance, and day-to-day jobsite flexibility.
When properly selected and positioned, these units provide measurable benefits across safety, compliance, and day-to-day jobsite flexibility.
Improves Air Quality and Safety
A HEPA air scrubber with filters reduces airborne particle concentrations in active work areas by continuously removing contaminants generated during construction and renovation.
In healthcare environments, this includes fine dust, microbial particles, and other bioaerosols that are not visible but can impact patient safety. By lowering the overall particle load in the air, these units help reduce exposure risks for workers and limit the potential for contaminants to enter adjacent clean areas.
This is particularly important in anterooms, where controlling airborne particles directly affects how much contamination can move into occupied spaces.
In healthcare environments, this includes fine dust, microbial particles, and other bioaerosols that are not visible but can impact patient safety. By lowering the overall particle load in the air, these units help reduce exposure risks for workers and limit the potential for contaminants to enter adjacent clean areas.
This is particularly important in anterooms, where controlling airborne particles directly affects how much contamination can move into occupied spaces.
Supports Compliance and Infection Control
HEPA air scrubbers are a key component of infection control strategies in healthcare construction. Within an ICRA framework, they support containment by reducing airborne particulate levels and helping maintain controlled airflow conditions.
When used correctly, these units contribute to:
When used correctly, these units contribute to:
- Lower particle concentrations within containment areas
- Reduced risk of airborne contamination escaping into clean zones
- Alignment with infection control protocols and environmental health and safety (EHS) expectations
In many cases, the use of HEPA filtration is not optional but expected as part of a properly designed containment system.
Flexible for Different Work Environments
Portable HEPA air scrubbers can be deployed in a wide range of environments, from small anterooms to larger construction zones within occupied facilities.
They are commonly used in:
This flexibility makes them a practical solution for both planned containment systems and dynamic jobsite conditions where airborne particle levels can vary throughout the day.
They are commonly used in:
- Temporary containment setups during phased construction
- Healthcare renovation projects requiring strict infection control
- Industrial or commercial spaces with high particulate generation
Because these units are mobile and do not require permanent installation, they can be positioned where airflow control is most needed and adjusted as project conditions change.
This flexibility makes them a practical solution for both planned containment systems and dynamic jobsite conditions where airborne particle levels can vary throughout the day.
Partner with Higgins for More ICRA and Air Scrubber Expertise
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 through our HEPA air scrubber consulting services. 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.
