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FAQs about Equipment for Facility Construction and Renovation

Frequently Asked Questions about Abatement Technologies® Portable Air Scrubbers (PAS) for Removing Airborne Particles in Healthcare Settings


Why is negative pressure important to construction projects?

A negative pressure environment will help to contain the construction dust and contaminants within the construction space. A negative pressure space eliminates the possibility of contaminants passing outside of the construction area through leaks in the construction barriers.


How do I create a negative pressure environment using Abatement PREDATOR® and HEPA-AIRE® Portable Air Scrubbers?

In order to create a negative pressure environment, more air must leave the space than enters it. First of all, the construction area must be walled off with Abatement Technologies Containment Barriers. Secondly, the Abatement Portable Air Scrubber(s) must be placed inside the construction area. Ductwork should be run from the system to somewhere outside of the construction area, preferably to the outside of the building. Since the air is HEPA filtered, it is not mandatory to exhaust air to the outdoors. Learn more about the Principles and Importance of Negative Air Pressure and view the configuration animations.


Which size Abatement Portable Air Scrubber is needed for my current project?

Six or more air changes per hour (ACH) are recommended for effective air cleaning during construction and renovation work. To determine the amount of airflow and the number of PREDATOR or HEPA-AIRE PAS units required for your project, view the air change calculator for facility construction and renovation projects in healthcare facilities.


How is the amount of airflow that must be removed from the containment zone to maintain negative pressure calculated?

The general rule of thumb is that at least 10% more air must be exhausted from the area than is supplied to it. For example, if 500 CFM is coming in through the facility HVAC system, then at least 550 CFM must be filtered and exhausted by the PAS.


Why do I need to monitor room pressure where I am removing airborne particles, odors and infectious diseases?

Air flows from a higher pressure to a lower pressure. The PREDATOR or HEPA-AIRE PAS creates a negative pressure in the room so that airborne particulates are pulled towards it and filtered out. The negative pressure prevents particulates from leaving the room you want to cleanse and contaminating adjacent areas. Room pressure differences must be monitored and maintained to be effective. The most reliable and sure way to confirm that pressure relationships are correct is to continuously monitor differential pressure using Abatement’s PPM3-S Portable Differential Pressure Monitor.


What if we don't/can't exhaust the filtered air to the outside?

Since Abatement Technologies Portable Air Scrubbers pull the air through a true HEPA filter tested and certified to a minimum efficiency of 99.97% @ 0.3 microns before it is exhausted from the containment space, there is no requirement that they be exhausted to the outdoors.


Will Abatement PREDATOR and HEPA-AIRE Portable Air Scrubbers remove odors?

Yes, when equipped with special 2-inch deep VAPOR-LOCK® carbon filters available for all PREDATOR and HEPA-AIRE PAS models. These high-performance filters provide substantially more absorption capacity than most other carbon filters and meet most odor control requirements. Special carbon blends are also available for capturing odors from low molecular weight compounds for which carbon has limited effectiveness.


Which particulates can Abatement Portable Air Scrubbers capture?

All models (PREDATOR and HEPA-AIRE) are equipped with HEPA filters that are tested and certified to remove 99.97% of particles that are 0.3 microns and larger, to provide "operating room clean" filtered air. To put this in perspective, the diameter of a human hair is 50 to 200 microns, and fungal spores are typically five to 25 microns. For a complete list of particulate contaminants and odors that the Portable Air Scrubber can remove, please Contact Us with your fax number.


Why is HEPA filtration required during construction and renovation projects?

According to the latest 2003 CDC Guidelines for Environmental Infection Control in Health-Care Facilities HEPA filtration is required for the capture of microbial spores and other contaminants that can potentially cause fungal infections and Aspergillosis. Airborne bacteria and fungi are typically 3 microns (0.0001”) and smaller in size, small enough to easily pass through most filters. Air filtration devices must, therefore, be equipped with true HEPA (High-Efficiency Particulate Air) filters, designed to capture at least 99.97% (9,997 out of 10,000) particles as small as 0.3 microns (0.00001”) in size.


Are there any special requirements for HEPA filters used in healthcare facilities?

Yes. To meet Institute of Environmental Sciences and Technology IEST-RP-CC001.3 standards for Type A 99.97% efficiency HEPA filters, each and every completed filter must be individually tested for leakage and resistance, to detect any leaks in the media or between the media and the frame or other problems that can compromise the integrity of the completed filter. Test results must be shown on a label on the filter frame. Filter frames should be metal. The 2003 CDC Guidelines state that: “Wood (HEPA frames) can compromise the air quality if it becomes and remains wet, allowing the growth of fungi and bacteria,” and recommends replacing these filters with metal-frame filters. Filters should also meet UL900 Class II flammability requirements.


What are the differences between Abatement Portable Air Scrubbers and Negative Air Machines?

We manufacture both types of products. Although they perform similar functions, they have distinctly different designs and markets. Big, boxy and heavy negative air machines with ‘no frills’ designs and hard casters are lower priced, but are best suited for large projects in unoccupied facilities. Abatement PAS have a much lighter weight, upright design that makes them much more portable and easy to roll into and maneuver through tight spaces with minimal disruption to an occupied facility. Higher performance motors, blowers and filtration systems substantially improve airflow output and filter life and reduce operating costs. More elaborate controls and high tech stainless steel cabinets that look great and are easy to clean add to their ‘hospital friendliness’. Learn more about Abatement Technologies line of high-performance PREDATOR and HEPA-AIRE Series Portable Air Scrubbers.


Can Abatement Portable Air Scrubbers also be used to filter and recirculate air or for positive pressure?

Definitely. Abatement PAS units can be used to continuously filter and recirculate 100% of the filtered air within the construction area. This will boost the ACH in the room and provide HEPA filtration, but will not change room pressurization. All models can also be configured to create positive pressure.  


Does Abatement Technologies offer any solutions for capturing and removing particles that drop out of the air and land on walls, floors and other surfaces?

Yes. Surfaces should be frequently cleaned with a HEPA vacuum to further reduce the chance that harmful particles could migrate out of the area and become airborne again. Abatement Technologies offers two HEPA vacuum models, the V8000WD Canister Style, Wet/Dry HEPA Vac and the V1300H Hip-Mounted HEPA Vac.


How often do Abatement HEPA filters need to be changed?

The size and concentration of airborne contaminants, temperature, humidity conditions and duration of use determine how often filters need replacement. As the filters become loaded with particulate matter, the airflow capacity of the unit decreases and the static pressure differential across the filter increases. 

Abatement Portable Air Scrubbers are equipped with easy-to-read filter change indicator lamps that illuminate when filters should be replaced. Unlike gauges, these lamps do not require operator interpretation or calculations. Average filter life (with continuous operation):

  • Primary filter: 1 day
  • Secondary filters: 3-7 days
  • HEPA filter: 800 hours


What are the total cost-savings of using Abatement PAS versus the competition?

Abatement PAS can potentially save users up to $10,000 or more over the life of the unit compared to other systems, including low-priced (and generally low-quality) “economy” products. Four main factors contribute to these savings:

  1. Longer filter life because the filters provide exceptional dirt-holding capacity
  2. Lower replacement filter costs
  3. Lower labor costs due to higher productivity
  4. Minimal downtime. By any measure, this is an excellent return on investment.


What does Abatement mean by “aircraft-type construction”?

Our stainless steel units are manufactured using solid rivet construction, for the same reasons aircraft manufacturers use them–solid rivets are exceptionally strong, durable and leak-resistant. In addition, closed-cell neoprene gaskets between the two layers of metal further ensure that critical seams are airtight. Sheet metal screw, hollow pop rivets, or nuts and bolts are far cheaper, but they are also far more prone to failure and leakage. Would you want to fly on an airplane made that way?


What Abatement accessories are needed for negative pressure applications?

PREDATOR and HEPA-AIRE Portable Air Scrubbers include an exhaust collar and a special locking clamp for attaching flex duct to the collar. Flex duct and other items are sold as accessory products.


What is the warranty of Abatement Portable Air Scrubbers?

All systems are covered by a comprehensive limited warranty to the original user against defects in materials and workmanship for a period of one year after date of purchase. This warranty excludes filters, which are consumable items that require ongoing replacement.


What is the estimated shipping time of Abatement PAS?

We do our best to keep all Abatement Portable Air Scrubbers in stock for same day or next day shipment when possible. Approximate shipping time within the continental United States is two to seven days. You will be notified immediately of the estimated delay should we experience extremely high demand and the system you order happens to be out of stock.



FAQs about Product Safety Certification

You really emphasize the fact that Abatement products are tested and certified by ETL, a Nationally recognized testing Laboratory (NRTL). What are the requirements?

In the USA, OSHA safety standards for general industry and construction and the National Electrical Code require testing and listing (certification) of electrical products to applicable standards. It is important to note that this testing must be performed on an electrical device even if the individual electrical components used in that device are all listed or approved. Testing must be done by an OSHA-recognized NRTL, such as UL (Underwriters Laboratories), ETL (Environmental Testing Laboratories) or CSA (Canadian Standards Association). In Canada, The Standards Council of Canada has adopted standards for the Canadian Electrical Code developed on its behalf by the Canadian Standards Association (CSA). Third party testing from a laboratory or other organization, not NRTL-certified is not acceptable, even if such testing is done to applicable standards.

Why is NRTL certification so important?

Unless a unit is properly tested, users have no way of knowing whether it is properly and safely designed to meet the requirements of the applicable electrical codes. It is wise to require written vendor verification that the products you purchase are NRTL certified.

Aren't all air filtration products properly certified?

No. Unfortunately, many of the air filtration systems sold to and used by contractors, healthcare facilities and others are not certified, especially negative air machines.


FAQs about HEPA Filters

Commonly Asked Questions about HEPA Filter Performance & Testing Requirements

What does the term HEPA mean?

HEPA is an acronym for "High-Efficiency Particulate Air" or "High-Efficiency Particulate Arrestance." This acronym refers to a filter that is manufactured, tested and certified to meet Institute of Environmental Sciences and Technology (IEST) construction, performance and certification standards as currently published in IEST RP-CC001.3.


How long have HEPA filters been in use?

The first HEPA filters were developed for the Atomic Energy Commission during World War II for use in facilities manufacturing components for the Manhattan (atomic bomb) project. These HEPA filters were originally designed to capture microscopic radioactive particles too small for effective removal by existing types of filters. HEPA filters used today are much more efficient and economical than the products made in the 1940's.


Where are HEPA filters used today?

HEPA filters are generally specified for applications where microscopic airborne particles or biopollutants could cause human health or product quality problems. Typical users include military, nuclear, pharmaceutical, electronics, biological and medical facilities.


What is it that makes HEPA filters so efficient?

The ultra-fine, glass-fiber medium captures microscopic particles that can easily pass through other filters by a combination of diffusion, interception and inertial impaction. To qualify as a Type A HEPA filter, the filter must capture at least 99.97% (9,997 out of 10,000) of particles 0.3 microns in size–about 300 times smaller than the diameter of a human hair, and 25 to 50 times smaller than we can see. To a HEPA filter, catching a one-micron particle (1/1,000,000 of a meter) is like stopping a cotton ball with a door screen. 


Are filters this efficient really necessary for IAQ applications?

Laser particle counter measurements typically show that more than 99% of the particles suspended in indoor air are one micron (1/1,000,000 of a meter) or smaller in size. EPA calls these “lung-damaging” particles, because they can lodge deep in the lungs when inhaled. The ability of HEPA filters to capture particles this small is what sets them apart from other types of filters. Regulations developed by EPA, OSHA, CDC and other federal, state and local government agencies responsible for human health and IAQ issues specify HEPA filters for asbestos, lead and mold abatement, TB and SARS isolation rooms and healthcare renovation projects.


Are all filters made with HEPA filter media HEPA filters?

Manufacturing a filter with HEPA filter media does not mean that the filter itself meets true HEPA efficiency requirements. Serious filter leakage can go undetected if filters are not individually tested and certified at the end of the manufacturing process. Even the tiniest pinhole leaks in the media or breach of the seal between the media pack and the filter frame can cause the filter to fail IEST requirements. The testing requires very specific procedures using a thermally generated mono-dispersed aerosol and a laser particle counter. Some regulations also require field-testing by the user prior to going into service and periodically thereafter.


Why is the testing done with a 0.3-micron particle size test aerosol?

Filter efficiency studies have shown that 0.3-microns is the "Most Penetrating Particle Size (MPPS)" for HEPA filter media. Efficiency is typically greater than 99.97% against larger or smaller particle sizes. Particles larger than 0.3 microns are typically more easily trapped or intercepted, by the media. Smaller particles often lack sufficient mass to penetrate the media.


Is a "HEPA-Type" filter the same as a HEPA filter?

No. In fact, the differences are huge. According to the American Lung Association, filters classified as "HEPA-type" filters may capture as little as 55% of 0.3-micron particles (5,500 out of 10,000). By this definition, the true HEPA filter could be more than 1,800 times as efficient as the "HEPA-type" filter.


Does HEPA filter efficiency decrease as the filter gets dirty?

No. Unlike electronic air cleaners and other air purification technologies that experience substantial loss of efficiency as they become dirty, exactly the opposite typically happens with HEPA filters. In fact, the dirtier a HEPA filter gets, the more efficient it can become.

AIRE Guardian Containment Cube

“We have successfully used our Abatement Portable Air Scrubber during construction projects without any patient or staff complaints.”
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