Building Science and the Prevention of COVID-19
Let’s be clear, building science will never take the place of essential, individual behavior, like social distancing, handwashing and limiting the frequency with which we touch our faces. However, there is strong evidence that building science has a role to play in controlling indoor environmental quality, which, in turn, can control the spread of viruses like COVID-19.
The benefits of controlling a building’s environment go well beyond preventing the spread of viruses. In fact, it’s the first step to significantly lowering energy costs, reducing carbon emissions and improving indoor air quality for everyone. There are a few steps that are essential to operating high performing buildings. Good news: it doesn’t cost a premium to reach these levels of performance.
High Performance Starts with the Building’s Envelope
The gold standard for controlling a building’s environment is Passive House, which relies on a few fundamental principles that result in ultra-low energy use and ultra-high indoor air quality. In the simplest terms, Passive House looks holistically at buildings and sets expectations for building performance in operations.
Designing and constructing a high-performance building envelope is the first step to achieving the Passive House standard. Embedded in Passive House are performance expectations for ventilation, airtightness, fenestration, climate-specific insulation, and the elimination of thermal bridges. Once a plan includes a high-performance building envelope, decisions around active mechanical systems and renewables become cheaper and easier.
Many building owners and developers make the mistake of putting the discussion of renewables at the beginning of a project. Whether building new or renovating an existing building, the discussion of renewables should always come last after building loads are reduced. This small point is a key indication of a team’s willingness or ability to look at a building’s design and/or construction holistically.
Control Over Ventilation Brings Broad Benefits
Passive House’s role in controlling the spread of viruses like COVID-19 rests in its required ventilation and filtration performance standards. While there are many ways to design ventilation to meet a variety of performance goals, ventilating with outdoor air is essential to controlling the spread of viruses and diluting airborne contaminants.
Recently, Timo Smieszek, Gianrocco Lazzari and Marcel Salathe published the results of a study that centered on a US high school. The study looked at the potential of ventilation to control droplet- and aerosol-transmitted influenza. The study found that bringing ventilation to recommended levels had the same mitigating effect as a vaccination coverage of 50-60%. These findings imply that building science-based design and construction can, indeed, play a role in controlling the spread of viruses in buildings.
Filtration Without Sacrificing Performance
In addition to ventilation, Passive House also sets high standards for air filtration, requiring MERV 13 or higher for outdoor air filters. Research shows that high-efficiency air filters can remove 99.97% of particles that are 0.3 microns in diameter. HEPA filters are largely recognized to have MERV values between 17-20. These filters have been shown to remove dust, vapors, bacteria, fungi and effectively capture viral particles that may transmit infections.
A Little Humidity Goes A Long Way
Viruses prefer dry environments. Using highly efficient ventilation systems with heat and energy recovery to boost humidity takes some thought, because humidity must be balanced with temperature to keep building occupants comfortable. We recommend building owners consider how they want to balance temperature and humidity to accomplish their thermal comfort goals. Research suggests that a modest increase in humidity levels could be a scalable intervention to decrease influenza or other viral outbreaks.
Connect Goals to Operations
There has never been a better time, in terms of public awareness and technological innovations, to begin monitoring and measuring your building’s indoor air quality. One way to do so is with RESET Air, an international performance-based standard and certification program for healthy buildings. RESET Air continuously measures and displays air-quality data in real time, using monitors to track particulate matter (PM2.5/PM10), carbon dioxide, total volatile organic compounds, temperature, and relative humidity. Results stream to the cloud and can be viewed from any computer or mobile device.
RESET Air is comprised of three distinct standards. First, RESET Air’s Accredited Professionals develop the monitor deployment plan for a building. RESET Air then accredits monitors, which must be commercial grade. Lastly, RESET Air Accredited Data Providers ensure the reliability of performance data measured and reported to building occupants.
The benefits of monitoring and measuring indoor air quality performance provides assurances that your building is performing as expected and doing the best it can to prevent the spread of viruses like COVID-19.
Why it Matters
We know that, on average, Americans spend approximately 90% of their time indoors where the concentrations of some pollutants are often 2 to 5 times higher than typical outdoor concentrations. As we battle COVID-19, our time indoors is only increasing. Doing our part as humans to reduce the spread of viruses is essential, but the performance of our buildings can complement -- perhaps even enhance -- our individual contributions. Passive House and RESET Air are two affordable performance standards that provide enhanced levels of ventilation, filtration, measurement, and verification to alleviate the spread of COVID-19.
Builder's mission, backed by a 35-year tradition of journalism excellence, is to identify best business practices, new products, cutting-edge technology innovative construction techniques and ground-breaking design innovation to help industry professionals succeed.
Beth Eckenrode is co-author of the recently published book The Power of Existing Buildings. She is co-founder of AUROS Group and a certified RESET AP with Regenerative Ecological Social & Economic Targets. She is Fitwel Ambassador with Centers for Active Design’s Fitwel Certification Program and is a Strategic Advisor to the North American Passive House Network.