It is time to think about reopening and returning buildings to normal operations. Building closures or limited use during the COVID-19 crisis increases risk of bacteria growth in water systems and associated equipment. Building operators and facility managers must abate risk of waterborne pathogens, such as Legionella bacteria, the cause of Legionnaire’s disease, by developing a water management plan.

Guidance documents are available through the Center for Disease Control (CDC) Guidance for Reopening Buildings After Prolonged Shutdown or Reduced Operation. The American Society of Heating, Refrigerating and Air-Conditioning Engineers’ (ASHRAE) building readiness guidance offers resources and practical guidance for HVAC system operations amid the risk of COVID-19.

ASHRAE’s recommendations for reopening buildings are outlined in the frequently asked questions section of its COVID-19 Resources webpage. Recommendations include the following:

  • Create a strategic plan prior to opening a building. The plan should include measures to make occupants feel safer, ensuring supply chain for critical items such as filters and communication plans for building support and safety measures for occupants.
  • If the building opening takes place when Personal Protective Equipment (PPE) requirements are still in place, ASHRAE’s Occupancy Guides can be referenced to deal with functioning buildings during the epidemic.
  • Review HVAC programming to provide flushing two hours before and post occupancies. This includes operating the exhaust fans as well as opening the outside air dampers. For buildings without the capacity to treat large quantities of outside air and when outside air conditions are moderate, open all windows for a minimum of two hours before reoccupation.
  • Ensure that custodial scope includes proper cleaning procedures built from EPA and CDC guidance on approved products and methods:
    • Disinfect high-touch areas of HVAC and other building service systems (e.g. on/off switches, thermostats)
    • Disinfect the interior of refrigerated devices, e.g. refrigerators, where the virus can potentially survive for long periods of time.
  • Run the system on minimum outside air when unoccupied.
  • Garage exhaust, if any, should run two hours before occupancy.

Additional guidance is available in the ANSI/ASHRAE Standard 188-2018, Legionellosis: Risk Management for Building Water Systems.