As hospitals revisit and upgrade the performance of their HVAC systems to prevent the spread of COVID-19, the ASHRAE Epidemic Task Force has updated its guidance for HVAC systems to help mitigate the transmission of the illness.

The Building Readiness Guide includes additional information and clarifications to help designers and commissioning providers perform pre- or post-occupancy flush calculations to reduce the time and energy to clear spaces of contaminants between occupancy periods. Among the updates to the building readiness guidance include the following:

Flushing-time calculator. There is now a link to a view-only Google Sheet that can be downloaded for use, to help determine the available equivalent outdoor air changes and time to perform the flush. This sheet is based on a typical mixed air AHU with filters, cooling coil, with potential for in AHU air cleaner (UVC is noted in the example), and in-room air cleaning devices.

Heating-season guidance. The guide now includes data to consider for heating of outdoor air and the potential impact on pre-heat coils in systems.

Click here for a pdf version of the guide.