Principles and Importance of Negative Pressure Containment
Effective Negative Pressure Particle Containment Using Abatement Technologies® Portable Air Scrubbers
Particles released into the air during facility construction, renovation, demolition and maintenance activities must be properly isolated and contained. Tiny particles and fungal spores are lightweight enough to remain aerosolized (suspended in the air) for hours, days or even weeks. The aerosolized particles can migrate into other areas of a facility on air currents and pose a potential threat to the health of sensitive patients. Larger particles can create housekeeping problems when they drop out of the air and settle on floors and other surfaces.
How Negative Pressure Particle Containment Works
Abatement Technologies HEPA-AIRE® and PREDATOR® series Portable Air Scrubbers (PAS) are designed to contain and capture indoor air particles and other contaminants and odors using a time-proven technique known as negative pressure particle containment. Effective negative pressure containment requires four main elements:
- Construction of a physical barrier around the work area to separate it from the rest of the facility.
- Sealing off any HVAC return air grills within the space to protect against particles being pulled into the HVAC system.
- Continuously pulling air within the area through a HEPA filtration device to reduce the number of airborne particles. Most job specifications require at least 6 air changes per hour (ACH), which means that the device must filter a volume of air equal to the air volume contained within the enclosed space 6 times per hour, or every 10 minutes.
- Exhausting at least 10% more cubic feet per minute of clean, HEPA-filtered air out of the space than is supplied into it to create and maintain negative pressure within that space. This helps ensure that any air leakage between the contained area and adjacent spaces will be “clean” air flowing in and not “dirty” air flowing out.
Modes of Operation
1. Negative Pressure Mode with the Abatement Technologies Portable Air Scrubber Located Inside the Containment Zone:
The most common configuration is locating the Portable Air Scrubber within the contained work space and using it to propel clean, HEPA-filtered air out through flexible exhaust ducting.
2. Negative Pressure Mode with the Abatement Technologies Portable Air Scrubber Located Outside of the Containment Zone:
Space limitations within the containment zone sometimes require locating the Abatement Technologies Portable Air Scrubber in a nearby area. In these instances dirty air is pulled out of the contained area and fed directly into the scrubber inlet manifold through flexible ducting. The negative pressure inside the ducting by the air scrubber ensures that dirty air cannot leak from the ducting into the clean space. Filtered air can be exhausted into the area in which the PAS is located or ducted outdoors.
3. Continuous Air Cleaning and Recirculation:
Abatement Technologies Portable Air Scrubbers can be used as continuous air cleaners, with no affect on room pressurization, to facilitate the removal rate of airborne contaminants. The PAS is located within the containment zone with no inlet or exhaust ducting attached.
Click here for a spec sheet on the entire line of HEPA-AIRE Portable Air Scrubbers.
Click here for the Air Change Calculator.
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