USA: ASHRAE has developed proactive guidance to help address coronavirus concerns with respect to the operation and maintenance of HVAC systems.
ASHRAE’s COVID-19 Preparedness Resources webpage, ashrae.org/COVID19, provides easily accessible resources for building industry professionals. These include ASHRAE’s recently approved position document on airborne infectious diseases and links to the latest practical standards and guidelines.
“The recent escalation in the spread of coronavirus disease 2019 is alarming on a global scale,” said 2019-20 ASHRAE president Darryl K Boyce. “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.”
The position document advises that new and existing healthcare intake and waiting areas, crowded shelters, and similar facilities should go beyond the 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).
ASHRAE maintains that 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. These include 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 pressurisation, personalised ventilation, source capture ventilation, filtration (central or unitary), and UVGI (upper room, in-room, and in the airstream).
Owners, operators, and engineers are encouraged to collaborate with infection prevention specialists knowledgeable about transmission of infection in the community and the workplace and about strategies for prevention and risk mitigation.