COVID-19 Mitigation Strategies in HVAC Systems

Due to the effects of the COVID-19 pandemic, the world as we knew it has changed, forcing us to re-assess the way we approach building design.

As we navigate through the pandemic, it has become more of a priority than ever to create safer and healthier spaces for building occupants.

How can this be done?

Creating healthier environments requires an understanding of how the COVID-19 virus can spread and developing a strategy to minimize the spread. In this article, our team of mechanical engineers give their expert advice on mitigation strategies for heating, ventilation, and air conditioning systems (HVAC).

Understanding Droplets vs. Aerosols

Based on studies by the scientific community, one method of COVID-19 spread is by droplets and aerosols emitted when people breathe, speak, cough, and sneeze. Droplets are larger and heavier particles of spit or mucous. Studies show that droplets tend to spread 3 to 7 inches from the source. Since the particles are heavier, the weight of the particle causes them to drop within the air stream and settle onto surfaces that are within 3 to 7 inches of the source.

The CDC guidelines for social distancing are mostly based on droplets. Since the droplets can settle onto surfaces, including hands, desks, tables, steering wheels, phones, and any other surface, the CDC also stresses washing hands and repeated cleaning of surfaces or devices to prevent the spreading of viruses that may have settled on these surfaces.

Aerosols are lighter than droplets and can travel further distances from the source than droplets, thus raising the question of what can be done to reduce the spread or impact of aerosols.

Which HVAC systems do you focus on?

Asking questions about what the HVAC system can do to combat aerosols raises several questions about the mechanism for infection and what mitigation options are available through HVAC systems.

Questions may include:

• Does it take one virus particle or many particles to pass along the virus?
• Is virus dosage and exposure an issue and, if so, how can the HVAC system help to limit the dosage?
• What types of spaces are of most concern with the HVAC system?
• Which is more important, individual rooms served by dedicated systems or HVAC systems that serve large open spaces or multiple rooms occupied by multiple people?
• Is the concern focused on limiting spread or is the concern to get rid of the virus in every room?

HVAC System Strategies

Understanding the mechanism for the spread (aerosols vs. droplets) and understanding the goal of the building owners and occupants will help determine a course of action.

As has been determined by the CDC, a mitigation strategy involves many different elements including individual behavior, cleaning, building operations, and, as we are discussing here, HVAC systems.

Download Guide

Learn the HVAC system strategies that can help with mitigating infectious aerosols by downloading our quick and easy guidelines.