U.K., Oct. 10 -- Our knowledge of the COVID-19 virus and the engineering controls associated with mitigating its transmission have evolved considerably since the pandemic hit the US earlier this year. We now know that it is highly unlikely for COVID-19 to travel through a code-compliant, multi-zone, hospital HVAC system (return ductwork, central air handling unit coils, final filters, and terminal units). There are no known instances of COVID-19 transmission through this pathway as of this writing.
The use of 100 per cent exhaust (where there's no recirculation via central air handlers) is not justified, except for rooms where aerosol generating procedures are performed and in the Emergency Department, where there are significant numbers o...