COVID-19 Spurs Healthy Building Design Trends
On June 29, New York Governor Andrew Cuomo announced that the state’s shopping malls will be required to use air-conditioning systems capable of filtering-out the COVID-19 virus. To meet this requirement, HVAC systems will have to be equipped with high-efficiency HEPA filters, designed to filter particles as small as 0.01 micron (the COVID-19 virus is about 0.125 microns in diameter).
The Importance of Indoor Air Quality to Healthy Buildings
Cuomo’s announcement highlights the importance of indoor air quality as part of the long-term response to the COVID-19 pandemic. People spend a lot of time indoors — some up to 90% of their typical days – and lockdowns associated with COVID-19 response have only increased that indoor time. Many people around the world have spent most of the past several months inside.
With people spending so much time indoors, it follows that that most respiratory-disease transmission also occurs indoors. COVID-19 is but one of over 40 pathogens and allergens that can transmit disease through the air in a built environment. Creating a healthier indoor environment can not only lower our risk of transmitting disease, but also improve our health and our productivity. There’s also a huge economic benefit, estimated at up to $150 billion per year, to be gained from improving our indoor environment to reduce the occurrence of colds, flu and related illness.
Thinking about building a future that better manages risks of the COVID-19 and other health concerns aligns with architects’ and planners’ long-term goal of making the built environment healthier. While COVID-19 is not the only reason to fast-track “healthy building” planning and technology, it’s likely to bring such practices into sharp focus for some time to come. A “healthy” building will be designed and equipped to favor humans’ health, while reducing infectious diseases’ ability to enter and spread.
Controlling Air Infiltration
We can start to improve air quality by enhancing building weatherization. Weatherization — including housewraps, roofing membranes, and advanced insulation materials — can act as a “skin” to help prevent the infiltration of microorganisms, dust, pollen, and mold spores that produce infection, allergic responses and immune-system stress. And sealing-off infiltration will increase HVAC filtering efficiency.
There is an often-quoted phrase, “build tight, ventilate right” that applies. If you can’t control the airflow into the house, you can’t control the air inside the house! With a good building envelope in place, it supports air filtration, as discussed above, to catch and remove as many airborne pathogens as possible.
HVAC and Light Help Optimize Indoor Environments
Another way is to configure HVAC to control temperature and humidity so rooms remain a bit warmer and more humid (40%-60% relative humidity) than conducive for virus proliferation, but not so warm and humid as to favor the growth of mold and bacteria. Increasing the volume of fresh air pumped through a building will also reduce the amount of recycled infectious particles. Plus, studies have shown that increasing fresh-air volume improves our ability to think and perform cognitive tasks.
Ventilation flow also needs rethinking to promote good health. Many HVAC systems will need to be configured to help ensure outside air is drawn from safe locations – not, for example near another building’s exhaust vents. And interior ducting may need to be configured so air is circulated differently in a building’s high-occupancy areas.
Light is another important factor to consider. Sunlight can discourage the growth of certain pathogenic bacteria, viruses and fungi. Future-building designs will likely feature increased window area to allow more natural light to bathe the interior. And the U.S. Centers for Disease Control and Prevention recommends installing UVGI (ultraviolet germicidal irradiation) lamps in office buildings to allow regular antimicrobial scanning. Such lamps can sanitize both the airborne environment and surfaces.
The changes described above are just a sampling of many that must be addressed. COVID-19 will change how our public buildings – offices, apartments, hospitals, schools, and government – are designed, built and operated. The Coronavirus is accelerating the pace of change toward healthier buildings. Expect to hear a lot more about these issues in the years ahead.