In 2021, it has never been better to be in the air quality industry. Effective ventilation practices have always been at the top of mind for those within the mechanical trades. Tradespeople are constantly working together to ensure their customers receive the highest level of comfort in their buildings and homes.
Due to the COVID-19 virus, and the ensuing pandemic, politicians have come to realize the importance that clean and healthy indoor air can have on Canadians’ everyday lives. The health of our buildings has become a hot topic during the election campaign. It should also be noted that various levels of government have vowed to improve the ventilation levels within public buildings.
Since the first lockdown back in March 2020, manufacturers have come out with innovative products to address ways of improving the health and safety of our buildings. Although most of these solutions aren’t new types of technology, products that typically had a smaller share of the market are now starting to see more notoriety, explains William P. Bahnfleth, professor of architectural engineering at Pennsylvania State University and chair of ASHRAE’s Epidemic Task Force. “A lot of start-up manufacturers or companies that manufacture other products are getting into the business of making some kind of air cleaner using some version of established technology,” explains Bahnfleth. One example of this is the use of fog from sports stadiums or at the beginning of most rock concerts. This is less commonly known as trimethylene glycol vapour, which as it turns out is a mild disinfectant.
Back to the basics
The fundamental principle, for those in the mechanical trades, is that ventilation and good mechanical filtration are capable of achieving most of what building operators and contractors are looking for. “Buildings have to have outdoor air because that’s the basis of indoor air quality,” explains Bahnfleth. “You’re going to have ventilation that can be increased if it’s cost-effective. You need to have mechanical filtration because high levels of particulate matter are unhealthy whether or not there are pathogens in them. They can cause lots of health effects.”
Ensure your building has proper filtration and moisture control, said Gord Cooke, president of Building Knowledge Canada, and partner at Construction Instruction. He recommends keeping buildings between 40 and 60 per cent humidity.
When looking at mechanical filtration, there are minimum standards that need to be kept in mind. In recent years, “ANSI/ASHRAE Standard 62.1-2019: Ventilation for Acceptable Indoor Air Quality” changed the minimum requirement for filters from MERV 6 to MERV 8. Since the pandemic, indoor air quality (IAQ) experts are making the argument that this update could be pushed even further to MERV 13. “One of the things that I would have liked to have seen before the pandemic is MERV 13 become the minimum filter efficiency because of the evidence we have that having your air filtered at that level, all the time, is just good for health,” said Bahnfleth. This level of filter would get around 70 to 80 per cent of the particles that the industry is concerned with.
“If you went back to before ASHRAE Standard 62 omitted smoking, spaces like a restaurant dining room would have been 30 CFM per person and a bar would have been 50 CFM per person. One of the jokes with some of my friends on the task force is, if we had just not prohibited smoking indoors, we’d be a lot safer from COVID-19, at least,” joked Bahnfleth.
Additionally, there have been recent discussions looking at whether or not outdoor airflow rates should be higher. “We don’t have highly accurate guidelines on how much equivalent clean air it takes to make a space safe,” explains Bahnfleth. “But if you look at healthcare standards, where infection control is a priority, you typically have anywhere around six air changes, or up to 12 or even 15. That’s generally going through filters that are MERV 13 or 14, or in the case of airborne infection isolation rooms, a HEPA filter.”
According to the United States Environmental Protection Agency (EPA), a high-efficiency particulate air, or commonly referred to as HEPA filter, is a type of pleated mechanical air filter. It can theoretically remove at least 99.97 per cent of dust, pollen, mould, bacteria, and any airborne particles with a size of 0.3 microns. Bacteria usually are around one micron, while COVID-19 sits at around 0.06 to 1.4 microns.
The Lennox Ultimate Indoor Air Quality System, which is used in commercial applications, consists of RTU mounted MERV 16 filters, UVC germicidal light, and Humiditrol modulating hot gas reheat dehumidification which together is capable of removing 99 per cent of the virus, reports David Mackey, senior product manager of commercial products for Lennox International. The Ultimate IAQ system can be factory installed on any Model L rooftop unit, with no additional installation necessary for the contractor. They do recommend that the contractor confirm the static pressure capabilities of the unit to ensure it can handle the MERV 16 filter. The two-inch MERV 16 filter is a new development for Lennox and was released in May 2021. “While there are not silver bullets in the fight against infectious disease, there are improvements that can be made to your HVAC system to make it safer,” said Mackey. “When used properly with other best practices recommended by CDC and others; commercial filtration and UVC lights can be part of a plan to reduce the potential for airborne transmission of COVID-19 indoors,” he adds.
Additive air cleaners have become hot topics within the IAQ market. Products such as ionizers have popped up and are marketed as effective against the COVID-19 virus. By putting reactive substances into the air, they’re going to interact with anything that can be oxidized so there are organic gases in the air. Volatile organic compounds can be broken down into other things, reports Bahnfleth.
A recent study conducted by Portland State, Colorado State, and Illinois Institute of Technology titled “Evaluating a Commercially Available In-duct Bipolar Ionization Device for Pollutant Removal and Potential Byproduct Formation” looks at ionization in buildings. “The marketplace for air cleaning devices has become inundated with an array of technologies to meet the demand, including high-efficiency fibrous-media filters, disinfectant misters, and a variety of electronic air cleaners including ultraviolet germicidal irradiation (UVGI) lights, plasma generators, hydroxyl generators, ionizers, and more,” according to the study.
There isn’t enough industry standards nor federal agency oversight to determine the efficacy or potential unintended consequences for some of these products, per the report. “Air ionization has been shown in some peer-reviewed studies to decrease bacterial deposition to surfaces, inactivate airborne bacteria, remove airborne particles, and increase submicron particle deposition to surfaces. “An energy-saving, environmentally-friendly cleaning process allows commercial buildings to significantly reduce the amount of outdoor air required to operate,” explains Ross Evans, president of Solid Solutions Canada Inc. “This equates to a safer, more comfortable environment, that requires up to 30 per cent less energy to condition.” Bipolar ionizers, like EagleX Pro, can help with odour reduction in a living space and also breaks down harmful volatile organic compounds (VOCs).
“When these things are looked at independently, they don’t quite look as great as they might have appeared to be,” said Bahnfleth. “A huge question is, do we have the standards that are appropriate for reading products.” It has been difficult to come up with ways to test these types of cleaners as a chamber test would be needed. That’s where most of the controversy has been with additive air cleaners, he adds.
The study concluded that exposure to negative ions was associated with increased systemic oxidative stress levels, which is a biomarker of cardiovascular health. The study goes on the explain that engineers have been recommending bipolar ionization devices because of relatively low upfront costs for purchase and installation, low maintenance and material costs, and they do not introduce addition pressure drop to air handling units. The Building Owners and Managers Association (BOMA) recommends to “explore the possible use and efficacy of bi-polar ionization and other technology for the HVAC system that are effective against COVID.”
Tried and true
One product that isn’t new to the industry and has already become well established in the marketplace for IAQ is UV/C light. Research has been conducted on this technology since the 1930s when it was shown to be effective against measles. There are safety issues with this technology, but they are manageable, reports Bahnfleth. “I think technology is fully developed when you don’t have to ask the manufacturer to design your system for you. If somebody wants to do a UV system, they can do calculations themselves and figure out what they need; although it requires certain expertise.”
Another piece of technology available to market that advertises itself as effective against bacteria and viruses, such as the COVID-19 virus, is air purifiers. According to Aura Air, they are 99.9 per cent effective against viruses, bacteria, mould, and VOCs. These also remove airborne particles as small as 0.3 microns. There are four stages of purification to the product, including pre-filtration, ray-filtration, sterilization, and finally UV/C light. It also includes real-time detection and monitoring with dashboard functionality to monitor and control several devices at once. According to Roei Friedberg, CEO of Aura Air, the Centre for Disease Control and Prevention (CDC) and ASHRAE recommends increasing ventilation, installing room air purifiers, and installing disinfection capabilities inside of the central unit. “Aura is providing the two solutions for the indoor environment for the room itself. The device is doing the air circulation in the room, all the time. We’re doing the filtration and disinfection.”
Rebalancing the system
On the CDC website, they recommend a layered approach to reduce exposure to COVID-19. This includes increasing the introduction of outdoor air, ensuring ventilation systems operate properly, rebalance or adjust HVAC systems to increase total airflow to occupied spaces, turn off any demand-controlled ventilation controls that reduce air supply based on occupancy or temperature during occupied hours, use portable HEPA fan/filtration systems, use ultraviolet germicidal irradiation (UVGI) as a supplemental treatment, and run the HVAC system at maximum outside airflow for two hours before and after the building is occupied.
“If there were three technologies available that were demonstrated to reduce risk of infection, that was ventilation, mechanical filtration, and UV,” said Bahnfleth. “What we said about other technologies was that, we can’t endorse them in the same way because there’s not nearly the evidence basis for them. We’re not saying don’t use them. We’re saying that if someone wants to use them, they need to be aware that there is less that’s been published in the way of independent research on them. They need to look at that carefully.”