How to choose the right air filtration solution for construction-related projects, retrofits, & building improvements

Clean air solutions for construction-related projects in Canada are becoming more critical than ever today, as issues of liability, contamination control, customer relation management, and dependability play bigger roles in project design. 

Air filtration and clean air solution planning during building construction and improvements

Air filtration planning is important with new construction, expansion, or retrofit projects. For example, if a hospital or other entity is constructing a new wing or adding a whole new building, air filtration housings are needed for critical applications like hospital cleanrooms, labs, GMP Pharma, nuclear facilities, or other biological facilities.

What is the mechanical scope of building construction?

The mechanical scope includes air filtration. Terminal housings are supplied for cleanrooms or operating rooms and bag-in/bag-out housings for hospital isolation rooms, or for other exhaust air applications where the particulate in the airstream could pose a threat to human health. 

Typically the construction projects include engineers, mechanical contractors, and sheet metal contractors.

The use case is one where the end-user is planning a new expansion or a new construction project. A consulting engineer is contracted for the design phase. The engineering firm pulls together the mechanical, electrical, structural, plumbing, and all other sections of a project together, and air filtration falls under the mechanical section. New construction air filtration expert Abhishek Arora states, “Engineers come to us to ask for recommendations on air filtration solutions for each particular application. We can design solutions specific to each unique need the engineer has. We recommend selections for the engineer, write the specifications, and when the actual project goes out to tender, we also provide pricing.” 

What are some of the most important considerations for mechanical engineers when designing clean air filtration solutions?

“What should be taken into account when it comes to air filtration systems? First and foremost, we have to take into account the kind of application. For example, if it’s a critical application like a cleanroom or pharmaceutical setting or hospital, due diligence must be done when it comes to qualifying the right OEM housing and air filter manufacturers. We must also ask the OEMs about the factory acceptance tests they carry out on both the filters and the filter housings.”

Abhishek Arora

It’s important to be aware of the quality programs that OEMs follow in their manufacturing facilities. Two of the most important quality control programs are ISO 9001 and Nuclear Quality Assurance (NQA1).

When it comes to cleanrooms and other highly-sensitive areas, why is it important to fully weld instead of skip weld? 

The fully-welded method provides engineers and project managers peace of mind that there will be no leakage. If a housing is skip-welded and caulked, it could lead to contamination in clean spaces and pose a threat to human health for the people that work in the space.

With a fully-welded housing, the chance of contamination is slim. The fully-welded housings should also come with a lifetime warranty against leaks, so customers have peace of mind that there won’t be any leakages or contamination. 

Where are bag-in/bag-out systems used for air filtration?

Bag-in/bag-out is typically a system used where the airstream passing through the housing contains particles of concern – viruses, bacteria, and pathogens. Bag-in/bag-out systems are typically used in exhaust air applications like isolation rooms, where a patient kept in the isolation room has a terminal illness or infectious disease, or in a biosafety lab.

The bag-in/bag-out system is also used when conducting research on new vaccines or new medicines for viruses, for example, COVID-19, RSV, etc. In the research lab, when the maintenance personnel has to change out the air filter, it is important to ensure that  staff is not exposed to the pathogens being captured by the HEPA filter. There is a PVC bag that covers the enclosure and the maintenance. Basically, it’s a barrier between what’s inside the housing and the personnel.

Bag-in/bag-out filters are a prefilter section followed by a HEPA filter. The prefilters are typically MERV 8 to MERV 11. The prefilter will remove a high percentage of  3 to 10 micron-size particles -large dust particles. The key is to change the prefilter on a timely basis for optimal protection of the HEPA filter. Using a highly-efficient, long-lasting prefilter will not only save energy but will also better protect and extend the life of the much more expensive HEPA filters.  Read related: Bag-in/Bag-out Housings

What are the best prefilters to save energy, improve particle capture efficiency, and increase the life of HEPA filters?

Arora says, “I have seen applications where the customer was changing the prefilter every six months and the HEPA filters lasted over five years. And it’s important that it’s been tested to the ASHRAE 52.2, Appendix J, Addendum B standard, which is the conditioning test to confirm how the filter performs in real-life operating conditions, thereby giving its true MERV performance. So for example, if you’re buying a MERV 9 prefilter, make sure you ask the OEM for the ASHRAE test report to see if that MERV 9 filter is actually operating as a MERV 9.”

Arora gives an analogy, “For example, if you go to an electronics superstore and buy a 75” television and a couple of months later when you want to watch the Super bowl and all of a sudden the screen has shrunk down to only 50”, you would not be very happy with your purchase at that crucial moment. It’s the same with air filters. If you purchase a MERV-10 air filter, you wouldn’t want that filter to decrease in effectiveness to a MERV-8 after a couple of months. This happens with air filters that are not tested under the ASHRAE 52.2 Appendix B Addendum J standard.”  Read related: MERV Air Filter Testing in Canada

What kind of HEPA air filters are used in cleanrooms, hospitals, and pharmaceutical product production?

Typically ceiling-mounted HEPA panel filters are used in cleanrooms, hospital operating rooms, and pharmaceutical production. They are called terminal HEPA modules.

In Canada, hospitals can be quite congested. So when installing housings for a bag-in/bag-out filter, it’s important to make sure you install the unit where there is perimeter clearance for maintenance purposes. The unit can be customized by making sure the OEM can provide a vertical downflow or vertical upflow instead of horizontal flow. Customization is key when high purity is required. Arora says, “We have been able to customize many solutions catered to the end users’ needs to minimize the footprint, and when you minimize the footprint it also addresses sustainability which is top of our mind as a global community.” Read related: Air Filtration for the Pharmaceutical Industry

What are pharmaceutical industry requirements for new construction, retrofit or expansion projects?

The pharmaceutical industry requirements are different from hospital or nuclear industry needs because the pharmaceutical industry typically uses HEPA ceiling panel filters. They are called ‘terminal HEPA modules,’ and have high-purity requirements. The HEPA modules don’t allow more than a certain number of particles per million per cubic foot. A concentration of particles per million so low that a very high amount of air changes is required for the air to be constantly refreshed. HEPA filters used in pharma or life sciences applications are typically 99.99% or higher.

Based on whether it’s a grade A, B, C, or D facility, Arora recommends the type of housing necessary for the application. The housing must be fully room-side serviceable. Staff must be able to test the air filter and change the filter from the room-side as well as be able to actually inject the challenge aerosol.

How can a hospital, pharmaceutical production facility, or cleanroom space be better utilized to reduce carbon footprint and reduce the total cost of ownership? 

For example, with a traditional bag-in/bag-out housing, it’s 18 feet in length. But Arora says, “If I’m able to actually give engineers the same housing in six feet of length, that’s 12 feet of space that can be used for other purposes without actually having to build a new building or new room, thereby reducing possible greenhouse gases and costs associated that could actually be omitted by not constructing that additional room and doing more with less.”

If air filters do not have to be replaced as often, there is less waste and less transportation required. Also, less production is involved and less landfill area is required for disposal, as well as fewer labour costs for installation, change-outs, and disposal. Labour is more scarce these days and existing labour can be reallocated to other pressing issues. 

Hospitals are suffering from a scarcity of personnel and especially maintenance staff which is why taking proper measures to reduce the total cost of ownership (TCO) is very important. Read related: Reduce Carbon Footprint, Reduced Waste with Air Filtration

What are the specific needs of nuclear power plants in terms of air quality and air filtration?

When it comes to applications like nuclear power plants, safety and reliability need to be taken one step further. The type of welding solution being followed by engineers is crucial. Arora states, “We strictly follow ASME Section 9 Welding and at the same time the engineer can actually request to look at the qualification records of the welders that are employed by the original equipment manufacturer (OEM). One key consideration is to ensure the housings are fully-welded or at least skip-welded and caulked.  There should be no chance of any bypass in the housing. The OEM should be able to provide factory acceptance test reports for the filter housings. This is especially true when you have applications with pathogens or any particulates of concern in the airstream. Such pathogens can be a threat to human health.”

Another important consideration from Arora’s point of view is the OEM test. Arora says, “Each housing must be tested individually for leakage and its sealing mechanism. The housings and the HEPA filters certified and validated must be tested in situ and locally. All of this can be done properly, with minimal downtime.” 

The biggest concern in nuclear power plants and nuclear facilities is radioactive radiation and protecting people from the damaging effects. It’s crucial that end users follow stringent standards as dictated by the local nuclear safety authorities as it directly relates to personnel and public safety. Typically, nuclear power plants follow the AG-1 Standard, which is the air and gas Revision 1 Nuclear Standard. This AG-1 standard basically dictates what a typical nuclear facility or a nuclear power plant should use in facilities as far as equipment and air filtration equipment is concerned. OEMs typically follow the Nuclear Quality Assurance-1 (NQA-1) quality program along with following the design guidelines as per the AG-1 standard.

Arora says, “We have test reports for each of the HEPA filters that show their AG-1 adherence, we also have test reports for filter housings supplied to nuclear power plants that are constructed under the NQA 1 QL-1 standard, a quality program we need to keep in mind when designing or selecting the HEPA filter or the filter housing for a nuclear application.” Read related post on air filtration for nuclear 

What are the best ways to reduce the total cost of ownership (TCO) of air filtration solutions?

Arora says, “We actually have an online application called the LCC analysis which is called life cycle cost analysis.  This is proprietary to Camfil, which is basically an application where the real-time operating parameters are entered into the software and different air filters can be selected for the first stage, second stage, and third stage. We can actually show customers by comparing different filter solutions how much money they would save over time. Less pressure drop equals savings on electricity and filter maintenance labour.  I can publish a very accurate report for the customer expressing the optimal filter change-outs and the respective savings.”

How can cost savings under true operating conditions be determined? 

Camfil deploys mobile test ducts, vans housed with test ducts inside using various air filters. Arora says “We keep the test ducts running for weeks and months at a time. Our algorithm is recording all the changing conditions including the air filter pressure drop and the entering particles. We use that data and incorporate that into our LCC program.  All the data collected over time from hundreds of thousands of hours of leaving the mobile test ducts in place is used to predict performance in multiple applications.  It’s not theoretical, it’s actually real data that Camfil is able to obtain and analyze.”

Reducing downtime in air filtration 

When a certifying agency is conducting certification procedures for a HEPA filter, the aerosol should be injected directly into the filter housing locally versus injecting it remotely into the air handling unit. If it’s not a dedicated air handling unit, the aerosol can actually seep into other areas of the facility, contaminating other parts of the facility that should be kept clean. Room-side access, room-side testability, serviceability, and ease of maintenance are key in pharmaceutical applications. Arora states, “The faster you change out the filters in pharmaceutical applications, the less downtime required which equals higher output. Higher output equals higher revenue for the end-user and in turn benefits the customer.”

Arora’s recommendations

Arora recommends asking the right questions of the OEM, “Ask for the test reports from the OEM and make sure the OEM is the HEPA filter manufacturer. Also, make sure the OEM filter housing manufacturer is also the same OEM air filter manufacturer for compatibility purposes.”

When  filter life is extended, it basically ensures maintenance staff is less exposed to hazardous contaminants by changing filters less often. Arora gives an example, “If you provide a prefilter that lasts 12 months instead of a typical prefilter that lasts only three months, we know we are reducing the chances of someone being exposed to contaminants.”

Arora recommends fully insulated housings for outdoor installations to prevent internal condensation and to fully protect the housings. Moisture is detrimental to HEPA filters. 

To consult with an air filtration expert regarding any needs related to project engineering or project management or for further air filtration information, please use this contact form and a Camfil filtration expert will answer any questions you may have. 

About Camfil Canada Clean Air Solutions

For more than half a century, Camfil has been helping people breathe cleaner air. As a leading manufacturer of premium clean air solutions, we provide commercial and industrial systems for air filtration and air pollution control that improve worker and equipment productivity, minimize energy use, and benefit human health and the environment. Read more about Camfil Canada


Media Contact:

Phillip Ilijevski

Camfil Canada Inc.

T: 437-929-1161

YouTube video edited by Riley Beanish

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