Nowadays, our main goal is to minimize the transmission of COVID 19 coronavirus.

One of the transmission causes is the aerogenic transmission of small droplets (<5 microns), that are capable of travelling in big distances through air flows of HVAC system.

For this reason, businesses – organizations that human resources are employed in building premises, should emphasize in the HVAC operation according to the following steps:

• Equipment cleaning with certified liquids
• Personal Protective Equipment for maintenance personnel
• Increased HVAC operation time (24/7 if possible)
• Natural ventilation of the space
• Maintain humidity below 40-60%
• Avoid operating local units if possible (FCU, split units)
• Frequent filter replacement-cleaning
• Using of fresh air and recirculation avoidance
• Adjust discharge vents to keep them as far away from fresh air inlets
• Operate in low air speed
• Regular cleaning of air ducts with mechanical means
• Continuous WC ventilation (24/7)
• Adjusting air ducts in order to avoid direct contact with humans
• Create bypasses to existing network in order to avoid potentially polluted air loads
• Install local or central air disinfection using UVGI
• Install local or central air disinfection with HEPA filters

The above are suggestions for minimizing the chances of transmitting the virus from HVAC. However, committee guidelines for personal preventive and hygiene measures are also of high importance.

Modification actions should take into account the committee guidelines, HVAC design and risk assessment of each building.

Bibliography

• D1 (d) / GP oik.19957 / 20-03-2020 «Taking measures to ensure public health from viral and other infections during the use of air conditioning units in the Health Units» (ΑDΑ: 9ΙΥΧ465ΦΥΟ-9ΗΣ)
• ASHRAE Position Document on Infectious Aerosols, April 14, 2020
• Jankovic-ASHRAE_On_COVID-19-ForHellenicChapter