The potential airborne transmission of a virus makes your health club’s HVAC and filtration systems extremely important—especially as the seasons begin to change. Learn what you can do to mitigate aerosol spread by implementing new strategies at your facility.
Ongoing and emerging research continues to show that SARS-CoV-2, the virus causing COVID-19, is present in aerosols, meaning the virus can spread via airborne particles. Researchers still don’t understand how infectious SARS-CoV-2 present in aerosols are or whether or not it is a significant mode of transportation. Nevertheless, the potential airborne transmission of a virus makes HVAC and filtration systems especially important.
According to the WHO, “A well-maintained and operated [HVAC] system can reduce the spread of COVID-19 in indoor spaces by increasing the rate of air change, reducing recirculation of air and increasing the use of outdoor air.”
Most experts agree that increasing the amount of fresh air intake, maximizing filtration, and implementing enhanced purification strategies like UV-C, in addition to common safety practices like mask wearing and social distancing, can help minimize the density and concentration of COVID-19 in the air.
Four Key Strategies to Reduce Aerosol Spread
Lindsey Marr, professor of civil and environmental engineering at Virginia Tech University, outlined four key strategies to reduce aerosol spread of SARS-CoV-2 indoors in her Plenary Session on The Role of Aerosols in the Transmission of COVID-19 at the American Association of Aerosol Researchers (AAAR) conference.
- Wearing a mask to help prevent the spread of COVID-19 from person to person. IHRSA details the safety and efficacy of exercising in a mask and highlights some popular performance masks.
- Maintaining social distancing—exceeding six feet or 2 meters depending on the activity—to remove direct contact transmission by limiting contact with respiratory plumes and droplets.
- Ventilation and filtration to dilute virus aerosols, maintaining lower density and concentrations of any present virus in the air.
- Hygiene, including handwashing, which removes the chance for direct and indirect transmission. Cleaning floors and surfaces is also important because settled viral particles can re-aerosolize, putting them back into the air circulation.
In an article published July 29, 2020, IHRSA outlined the role health club HVAC systems could play in COVID-19 safety, focusing on three key areas: ventilation, filtration, and purification. This article digs deeper into how to go about implementing these strategies, especially as temperatures and climate conditions change.
Considerations for Increasing Air Exchange
According to the U.K. government’s “Working safely during coronavirus” guidance, “Ventilation is an important part of mitigating against the transmission of COVID-19. Ventilation into the building should be optimised to ensure a fresh air supply is provided to all areas of the facility and increased wherever possible. Particular attention should be given to areas where high intensity exercise activity takes place.”
According to Rudy Fabiano, AIA, president of Fabiano Designs, a room’s air volume is an important consideration, with higher ceilings offering some advantages. “A smaller room that has less air volume is a little more dicy and you should probably consider opening all doors and getting fresh air in and not using any fans to spread any potential viral load.” In this instance, clubs may need to consider the fan effect of flywheels on bikes or rowing machines.
The U.K. government guidance recommends limiting occupancy to a minimum of 100 square feet (or about 9 square metres) per person while sustaining ventilation flows, which “will increase the typical current 10l/s/p [liters per second per person] flow rate of ventilation to at least 20l/s/p, as fewer people are being served by the ventilation system.” They also recommend, to the extent your system is capable, providing 100% fresh air to avoid the recirculation of air from one space to another.
Moving classes outdoors or opening doors and windows to let in outdoor air may have been a no-brainer in many parts of the world experiencing mild summers or winters as clubs reopened. But for many places, such as the upcoming winter in the Northern Hemisphere or a hot, dry summer in parts of Australia, weather conditions will make this more challenging.
Fabiano says clubs will have to consider what is feasible for them. According to Bert Baiotto of The Ballard Group, Inc. in advice to health clubs, “To open up the amount of fresh air you may sacrifice the temperature and humidity levels within your space, but by the nature of bringing in more and more fresh air in the space that you can manage will make it a much safer space to be in because you dilute the indoor air with the fresh outside air.”
As club owners decide how much outdoor air to let in, they are advised to consider how indoor temperature and humidity will change when doors and windows remain open. Opening doors to circulate outdoor air dropped indoor humidity by as much as 20%.
Research published in Aerosol and Air Quality Researchsuggests a humidity of 40-60% is “optimal for human health” in indoor space. In dryer conditions, viral particles can travel further, and the tiny hair-like cilia inside the respiratory tract don’t function as well at expelling particles as they do in more humid conditions. Conversely, in humid conditions the virus survives for a longer period on surfaces. Another study published in PLoS ONE concluded that “cold and dry conditions were potentiating factors on the spread of the virus.”
This means health clubs located in regions with cooler, dryer air will need to balance the need for circulating sufficient outdoor air with maintaining optimal humidity levels indoors, which could have significant impacts on your system’s functionality. Baiotto points out that some cooling coils may not be able to handle dehumidifying. Those in a dryer climate may have to add humidification capabilities in order to accommodate drier, cooler outdoor air, which can be expensive and harder to do.
However, Baiotto doesn’t think humidity will significantly impact an HVAC filter as long as the system is not condensing. He says, “If you get to a point where you’re condensing and you get water on the filter it’s not good because the filter won’t capture anything—it’ll collapse and probably fall over.”
Swimming and spa pools and locker rooms bring up further considerations. Donaldo Visani, senior principal architect at Ohlson Lavoie Collaborative (OLC) says, “In these spaces, you want to have a lot of circulation and you want to keep the pressure that exists” and which is required for these areas to run effectively. He adds, “Pools are the lowest pressurized zone of the building typically—there’s a lot of exhausting of the air through that and if you open windows in a pool room you may compromise how effectively the HVAC system is working for the pool. And the rest of the building and may start migrating moisture [to] places you don’t want them to be. You definitely need your facility manager or someone who knows what they’re doing with the HVAC system to tweak that system so it does get out as much fresh air as you can and keep the humidity” in the optimal zone.
Member comfort is another factor to consider. Visani says, “Comfort-wise, everybody will expect things are going to be a little different these days. I think you can push the envelope a little bit on [people’s] comfort zones. People may be hotter than usual or colder than usual. If you explain that to members clearly that this is why we’re running fans, this is why you’re feeling cooler or hotter in this room…. If you have a good system in place and a good narrative about why it’s being done I think members will understand that this is part of the new normal.”
Filtration helps remove contaminants from the air as it passees through the HVAC system. A challenge with filtration is that COVID-19 containing droplets can be very small (10-15 micrometers), and many Minimum Efficiency Reporting Value (MERV) rated filters in commercial buildings won’t catch aerosolized particles, which can be as small as 5 micrometers.
Baiotto advises that “you can also look at your filtration system to bring up your MERV rating to see the particle size your filter will stop going from low to high. If you go to a higher number that will also trap particles in the filtration system. You just have to change it more often.” Even if a filter cannot catch all participles and particle sizes, an effective filtration system combined with air circulation and purification can significantly lower the amount of SARS-CoV-2 in the air.
Some health clubs have begun installing fan-only systems, which circulate, filter, and purify the air, but do not change the temperature or humidity.
Fabiano discusses one club he worked with that had such a system. He said, “In one club we put a fan only system in the locker room to reduce bacteria and odor in the air. These systems look like a big hair dryer or in the ceiling and like an air conditioner register. They suck air in and have a UV-C component in them to kill what passes through. UV-C is dangerous to humans so it has to be shielded and contained in a system.”
He adds, “At the end of the day, you can’t beat fresh air, more air, and distance to reduce the spread.”
Purifying the Air to Neutralize SARS-CoV-2
Purification is a process by which air is treated in order to kill microbes. Two highly touted purification strategies include ionization and UV-C light.
According to filtration/disinfection guidance from the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), ionization refers to “technologies [that] utilize various methods to create reactive ions in air that react with airborne contaminants, including viruses.” These ions supposedly create a reaction that deactivates the virus.
However, Baiotto cautions against relying on ionization technologies. “Ionization [is] really good for retrofit applications because they don’t need much space, but there’s no published data on those so we strongly caution against using those as a guaranteed way to capture droplets.”
ASHRAE recommends against ionization technology that can produce other contaminants that are harmful to health, like ozone. Baiotto says, “The more inexpensive [ionization technologies] tend to release ozone into the air, which causes other issues, like respiratory problems. If you look into those, I recommend getting the higher quality ones that reduces that output.”
This aligns with CDC’s statement to ASHRAE with regards to bipolar ionization technology, which says in part “If you are considering the acquisition of bi-polar ionization equipment, you will want to be sure that the equipment meets UL 2998 standard certification (Environmental Claim Validation Procedure (ECVP) for Zero Ozone Emissions from Air Cleaners) which is intended to validate that no harmful levels of ozone are produced. Relative to many other air cleaning or disinfection technologies, needlepoint bi-polar ionization has a less-documented track record in regards to cleaning/disinfecting large and fast volumes of moving air within heating, ventilation, and air conditioning (HVAC) systems. This is not to imply that the technology doesn’t work as advertised, only that in the absence of an established body of evidence reflecting proven efficacy under as-used conditions, the technology is still considered by many to be an ‘emerging technology.’
Ultraviolet energy is another purification strategy, which according to ASHRAE guidance, “Inactivates viral, bacterial, and fungal organisms so they are unable to replicate and potentially cause disease.” UV light can be used in the form of LED lamps, installed in HVAC ductwork, or mounted close to high ceilings (greater than seven feet up).
Products are available in the entire UV spectra, though ASHRAE says that while “the entire UV spectrum is capable of inactivating microorganisms, UV-C energy (wavelengths of 100 – 280 nm) provides the most germicidal effect, with 265 nm being the optimum wavelength.”
Baiotto says, “UV-C are more proven—they have some tested results on those. To incorporate those into an air handling system it has to be a purpose-built system. You need 3-4 feet in the air handling unit to accommodate putting these in. For ceiling-mounted ones you don’t want to have them directly discharging onto people, which would work good with upward ceiling fans.”
How Clubs Can Approach Their HVAC Systems
Fabiano says, “Most club operators have to take care of the air conditioning system even if you don’t own the building. Most people have a contract with a local air conditioning company to maintain the system by changing filters and checking the system on an annual basis. If you are unsure, I recommend you start with your HVAC maintenance company to see how to get more fresh air in the club. If you have an air control system, most likely there is a way to go up to a certain level of MERV but starting with your maintenance contact is the first step.”
Alexandra Black Larcom, MPH, RD, LDN, is the Senior Manager of Health Promotion & Health Policy for IHRSA. She spends her days working on resources and projects that help IHRSA clubs offer effective health programs in their communities, and convincing lawmakers that policies promoting exercise are an excellent idea. Outside the office you’ll most likely find Alex at the gym, running on the Charles River, or, in the fall, by a TV cheering on the Florida Gators.
The International Health, Racquet & Sportsclub Association (IHRSA) is a global community of health and fitness professionals committed to building their businesses and improving their communities’ health and well-being. The mission of IHRSA is to grow, protect, and promote the health and fitness industry, and to provide its members with the benefits that will help them be more successful. IHRSA and its members (health clubs and fitness facilities, gyms, spas, sports clubs, and industry suppliers) are dedicated to make the world healthier through regular exercise. For more information visit www.ihrsa.org.