The ability of COVID-19 too quickly spread via airborne transfer has become recognized over the course of 2020. It is now well understood that people being in the same place at the same time — especially indoors in air that is not being sufficiently filtered and recirculated — is a serious risk factor that is feeding the pandemic.
Creating and maintaining safe interiors is now a vital aspect of HVAC (Heating, Ventilation, and Air Conditioning) engineering — with logistics, space and office interior planning, and design-build solutions also coming into play.
That’s why Horgan General Contractor Inc. has been focusing on these issues over the past few months, staying on top of the latest science and engineering data so that we can help our clients ensure that their properties are as safe as possible.
The broad HVAC issues that should be dealt with as economic — and therefore social — interaction increases include steps that, at root, will ensure that proper air circulation will decrease the spread of COVID in the coming months:
- Outdoor air ventilation: A primary strategy is making sure that air inside an enclosed area is continually “updated” with fresh air, which can be as simple as strategically opening windows. As a tip sheet from the U.S. Environmental Protection Agency (EPA) puts it: “In general, the greater the number of people in an indoor environment, the greater the need for ventilation with outdoor air. In other words, the ventilation rate should be based on the number of people that occupy an indoor space (and a few other factors).”
- Outdoor air dampers: These are an integral part of central heating/cooling systems and opening them as wide as possible will lessen the percentage of perhaps-contaminated air being recirculated by increasing the percentage of fresh air being circulated.
- HVAC filters: Filters must meet certain specifications to block substances as small as virus particles (and the edges around filters must be properly sealed too). Filters are rated on the Minimum Efficiency Reporting Value (MERV) scale, with the highest rating being 16. The Centers for Disease Control and Prevention (CDC) recommends 13-rated and higher filters to prevent the spread of COVID.
- Portable room air cleaners: In buildings without HVAC systems — or as supplemental protection — a unit with a high-efficiency particulate air (HEPA) filter is required. But as with HVAC filters, the HEPA filters must be dense enough to capture COVID virus particles.
There is a host of complicating factors when dealing with the dynamics of airflow. For example, just sticking high-MERV-rated filters in an HVAC system might result in destroying it, since many are not designed to use filters rated at 13 or higher and the increased static pressure will lead to systemic failure. Likewise, HVAC systems are finely calibrated, so overriding specs and running with the dampers open presents serious trade-offs.
What it boils down to is, unless you have staff with specialized knowledge in these highly technical areas, bringing in an integrated project delivery company like Horgan is your best strategy for dealing with the realities of the age of COVID. If you have buildings you are responsible for in the suburban Philadelphia, northern Delaware, southern New Jersey, and Princeton areas, Horgan can deliver scientific expertise and commercial construction experience that you can depend on.
For further information, many organizations and governmental agencies have material available about this relatively complex field, including the resources page of the American Society of Heating, Refrigerating, and Air-Conditioning Engineers.