In response to the COVID-19 pandemic, ASHRAE, REHVA, and other industry authorities have published a ton of information on how to maintain occupant health and safety in buildings…. but what are the energy and sustainability impacts of these recommendations and how can we predict and react to them using building simulation? Bring a beverage of your choice and join CHIBPSA for a conversation on this subject, presented by Dr. Tommy Zakrzewski from HKS Architects.
Here’s what ASHRAE recommends:
– Increase outdoor air ventilation (use caution in highly polluted areas); with a lower population in the building, this increases the effective dilution ventilation per person.
– Disable demand-controlled ventilation (DCV).
– Further open minimum outdoor air dampers, as high as 100%, thus eliminating recirculation (in the mild weather season, this need not affect thermal comfort or humidity, but clearly becomes more difficult in extreme weather).
– Improve central air filtration to the MERV-11 or the highest compatible with the filter rack, and seal edges of the filter to limit bypass.
– Keep systems running longer hours, if possible 24/7, to enhance the two actions above.
– Consider portable room air cleaners with HEPA filters.
– Consider UVGI (ultraviolet germicidal irradiation), protecting occupants from radiation, particularly in high-risk spaces such as waiting rooms, prisons and shelters.
Here’s what REHVA recommends:
– Secure ventilation of spaces with outdoor air
– Switch ventilation to nominal speed at least 2 hours before the building usage time and switch
– to lower speed 2 hours after the building usage time
– At nights and weekends, do not switch ventilation off, but keep systems running at lower speed
– Ensure regular airing with windows (even in mechanically ventilated buildings)
– Keep toilet ventilation 24/7 in operation
– Avoid open windows in toilets to assure the right direction of ventilation
– Instruct building occupants to flush toilets with closed lid
– Switch air handling units with recirculation to 100% outdoor air
– Inspect heat recovery equipment to be sure that leakages are under control
– Switch fan coils either off or operate so that fans are continuously on
– Do not change heating, cooling and possible humidification setpoints
– Do not plan duct cleaning for this period
– Replace central outdoor air and extract air filters as usually, according to maintenance schedule
– Regular filter replacement and maintenance works shall be performed with common protective measures including respiratory protection