ShareCOVID-19 news in the HVAC&R sector
The IIR reviews the available information on the possible impact of air conditioning on the spread of COVID-19 and the recommendations for the operation and maintenance of HVAC systems. Furthermore, several national organizations called on their government to identify HVAC&R systems maintenance as “essential service”.
As response to the coronavirus (COVID-19) pandemic, REHVA – the European Federation of Heating, Ventilation and Air Conditioning (HVAC) associations – drafted “COVID-19 guidance” document on how to operate and use building services in areas with a coronavirus outbreak to prevent the spread of COVID-19 depending on HVAC or plumbing systems related factors. REHVA called the document an “interim document to be complemented with new evidence and information when it becomes available”. The precautions it contains are meant as an addition to the general guidance for employers and building owners that is presented in the World Health Organisation document “Getting workplaces ready for COVID-19”.
Crucially, the document states that humidification and air conditioning have no practical effect on transmission of COVID-19. Unlike some other viruses, SARS-CoV-2, the virus which causes the Covid-19 disease, is quite resistant to environmental changes and is susceptible only to high relative humidities above 80% and temperature above 30 ˚C. Heating and cooling systems, the document says, can be operated normally as there are no direct implications on Covid-19 spread.
The document includes practical recommendations for building services operation. In buildings with mechanical ventilation systems, increasing air supply and exhaust ventilation is recommended. In buildings without mechanical ventilation systems it is recommended to actively use operable windows.
Under certain conditions virus particles in extract air can re-enter the building. Heat recovery devices may carry over virus attached to particles from the exhaust air side to the supply air side via leaks. As a result, REHVA recommends turning off rotary heat exchangers during SARS-CoV-2 episodes. Virus particles in return ducts can also re-enter a building when centralised air handling units are equipped with recirculation sectors. It is therefore recommended to avoid central recirculation during SARS-CoV-2 episodes by closing the recirculation dampers.
Finally, the REHVA guidance document mentions that duct cleaning is not effective against room-to-room infection because the ventilation system is not a contamination source if guidance about heat recovery and recirculation is followed.
Based on the most recent research, Worldatlas specifies that “people using their home air conditioning are not at risk of infection, especially if they are remaining at home having no contact with the rest of the population. But when it comes to central air conditioning, situations may vary. Central air conditioning – which is usually installed at larger commercial spaces like shopping malls and at more modern apartments – does not introduce any risk of spreading COVID-19 because of its technical properties but possibly because it is usually used at places with a lot of people. Researchers have studied the air conditioning system on the cruise Diamond Princess which had almost half of passengers infected with COVID-19. They found out the particles of the virus on various surfaces around the ship. According to these researchers, the virus partially spread through the air conditioning system as it was not able to filter out the virus particles. Still, this does not mean that it was the air conditioning system fault for the spread. Simply, an infection was already existing among people on board, and the air conditioning helped in the spread as passengers remained on the ship, using the same air conditioning system”.
This information is not useless since, according to The Hindu website, in Maharashtra, a state in the western peninsular region of India, Health Minister on March 21 announced that the government had issued circulars directing people to restrict use of air conditioning in the wake of the COVID-19 spread. “The windows should be left open for the sunlight to enter while the air conditioners can be used wherever only important,” the circular reads.
Other resources related to the operation and maintenance of heating, ventilating and air-conditioning systems in the context of the spread of COVID-19 are available in particular from the following organizations:
- the Chinese Association of Refrigeration (CAR) released two recommendations including “Recommendations on the operation of air conditioning and heating systems coping with COVID-19”, available in FRIDOC;
- ASHRAE has set up a dedicated web page “COVID-19 Preparedness Resources”;
- AHRI published “Coronavirus: Guidance for HR professionals and employers” web page:
Finally, it should be noted that, in several countries, organizations have called their governments to exempt heating, ventilation, air-conditioning and refrigeration (HVACR) maintenance services from any restrictions being placed on travel and business operation during COVID-19 crisis.
In the United States, AHRI and nine other organisations representing North America HVACR industry have requested on March 18 that federal, state, and local authorities grant “essential business” status to HVACR technicians and engineers (1).
In Australia, AIRAH has written to federal, state and territory ministers and called on the government to clearly identify HVAC&R building maintenance as “essential services”. (2)
In Europe, ADC3R, ASERCOM, ECSLA, EHI, EHPA, EPEE and Transfrigoroute International, representing the HVACR industry, have called on EU Member State governments to “consider their services and manufacturing sites as critical to maintain the health, safety, productivity and comfort of citizens whilst measures are taken to contain the spread of the COVID-19 virus”. (3)
The IIR, for its part, will soon issue a statement calling for refrigeration services to be considered essential during the current health crisis caused by COVID-19 (4).
(1) Facility Executive website