On April 12, 2020, the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) released their position document on infectious aerosols. It stated: “Transmission of SARS-CoV-2 [the virus that causes COVID-19] through the air is sufficiently likely that airborne exposure to the virus should be controlled. Changes to building operations, including the operation of heating, ventilating, and air-conditioning (HVAC) systems, can reduce airborne exposure.”

According to Scott Little, Wiley|Wilson Project Engineer in the Mechanical Department, there are various strategies for mitigating the risk of transmission in an occupied building with regard to the HVAC system. “Exercising some strategies may help with disease transmission and can provide long lasting improvements to indoor air quality. We have been working with clients to uncover easy-to-fix issues with their building systems and to explore more involved solutions and upgrades,” he explained. “The process begins with a review of available building documentation (record drawings, equipment submittals, testing, adjusting, and balancing reports) followed by a building walk-through, if permitted by the owner. With a strong understanding of existing conditions, we can assess how well each strategy can be applied and then identify the cost implications.”

Some of the strategies that can be considered include:
• Increasing outdoor air
• Improving air distribution
• Adding indoor humidification
• Increasing air filtration efficiency
• Using ultraviolet disinfection in air handlers or directly in a room
• Employing bipolar ionization
• Utilizing portable air cleaners

Wiley|Wilson engineers often can find creative solutions that address areas of concern without requiring capital improvements or costly upgrades. “We are available to help our clients understand their options for providing a safe environment for employees and to provide professional recommendations for implementing various strategies for their systems,” Scott said.