by Emell Derra Adolphus

In an effort to provide guidance and fight the further transmission of the coronavirus (COVID-19) as HVAC professionals, ASHRAE recently released proactive guidance in the form of a prepardness resources web page.

The page addresses concerns about the operation and maintenance of HVAC systems to prevent the spread of contagions while underscoring the use of the organizations standards to keep building systems healthy.

Standards referenced in the guide include:

“The recent escalation in the spread of coronavirus disease 2019 is alarming on a global scale,” says 2019-20 ASHRAE President Darryl K. Boyce, P.Eng. “While ASHRAE supports expanded research to fully understand how coronavirus is transmitted, we know that healthy buildings are a part of the solution. ASHRAE’s COVID-19 Preparedness Resources are available as guidance to building owners, operators and engineers on how to best protect occupants from exposure to the virus, in particular in relation to airborne particles that might be circulated by HVAC systems.”

ASHRAE also advises that new and existing health care intake and waiting areas, crowded shelters, and similar facilities should go beyond their minimum requirements, using techniques covered in ASHRAE’s Indoor Air Quality Guide to be even better prepared to control airborne infectious disease (including a future pandemic caused by a new infectious agent).

Because small particles remain airborne for some period of time, the design and operation of HVAC systems that move air can affect disease transmission in several ways, such as by the following:

  • Supplying clean air to susceptible occupants
  • Containing contaminated air and/or exhausting it to the outdoors
  • Diluting the air in a space with cleaner air from outdoors and/or by filtering the air
  • Cleaning the air within the room

ASHRAE recommends the following strategies of interest to address disease transmission: dilution ventilation, laminar and other in-room flow regimes, differential room pressurization, personalized ventilation, source capture ventilation, filtration (central or unitary), and UVGI (upper room, in-room, and in the airstream).