11 May 2020

How to use buildings safely during an epidemic?

In this time of a virus pandemic, we also have to change some everyday habits – including those related to the use of buildings. Despite all the difficulties we face in our basic everyday practices, this can also be an opportunity to simultaneously reduce the pressure on resource use and the impact of human activities on climate change, which is a significantly greater threat than the current pandemic.

To facilitate understanding of the measures, we first offer a glance onto key facts. The SARS-CoV-2 virus is very small, measuring 80 to 140 nanometres, or about three hundred times larger than a nitrogen molecule. We assess risks according to the concentrations of viruses and the probability of transmission or infection, and it depends on our actions how much we expose ourselves and others around us to such risks. In the context of a pandemic or an epidemic, therefore, a change in social dynamics is also crucial, where an individual changes his or her habits with an awareness of community protection, and not just for his or her own well-being.


Figure 1: WHO reported mechanisms of SARS-CoV-2 droplet exposure (dark blue). Light blue: the airborne transmission mechanism known for SARS-CoV-1 and seasonal influenza, currently specific evidence of SARS-CoV-2 is not yet available (Figure: Francesco Franchimon; SOURCE: REHVA).

In terms of contact transmission of viruses and microorganisms, we already wrote about how we can reduce the risk of transmission from door handles (www.odpriznogo.si), one of the “hotspots”. For example, a study conducted in offices, hotels, and medical facilities found that the virus was transmitted from one door handle to 40-60 percent of building users in just two to four hours.

Figure: Transfer pathways (Source: Leslie Dietz et al., 2020. Novel Coronavirus (COVID-19) Outbreak: A Review of the Current Literature and Built Environment (BE) Considerations to Reduce Transmission).

  • virus particles accumulate in the lungs and upper respiratory tract;
  • droplets and aerosol virus particles are eliminated from the body through daily activities such as coughing, sneezing, talking, and can spread to the surrounding area and individuals;
  • virus particles secreted from the mouth and nose are often found on the hands and can spread to objects that we touch frequently.

How to remain energy efficient, healthy and productive during quarantine and accompanying measures? Four international projects, co-funded by the Horizon 2020, have prepared a campaign called Hero at Home, which aims to show how we can all be heroes in the context of our homes. In addition to the UtilitEE, TripleA and eTEACHER projects, MOBISTYLE project also contributes to the campaign. The current situation is a challenge for our mental and physical health, productivity and, last but not least, it also affects our energy bills, as a longer presence in living spaces also means higher energy use. Using the hashtag #HeroAtHome, which you can follow on Twitter and Instagram, European experts are preparing practical tips to help us cope better with the new situation in our homes. Helpful and simple tips to save energy while providing a healthier indoor environment, better well-being and productivity, range from the best ventilation methods to switching off electronic devices, from ergonomics to temperature training.

The current situation shows a clear need for an interdisciplinary approach to problem solving. Building systems, with their function of providing comfort in buildings, are no longer merely marginal, but have become key elements that can have a significant impact on the risks of transmitting infections. Jure Vetršek, MSc, project manager at IRI UL, recently participated in a well-attended webinar organized by the European Federation of National Associations for Heating, Cooling and Ventilation (REHVA). The event was also broadcast by the European portal for energy efficiency of buildings BUILD UP. Together with representatives of the Laboratory for heating, sanitary, solar and air-conditioning engineering of the Faculty of Mechanical Engineering of University of Ljubljana, we also translated into Slovenian the REHVA guidelines on How to operate and use building services in order to prevent the spread of the coronavirus disease (COVID-19) virus (SARS-CoV-2) in workplaces. Together with the University Investments Office, we also organized training on key measures and guidelines for the representatives of University of Ljubljana members.

Summary of key practical measures for building services operation include:

  1. Secure ventilation of spaces with outdoor air
  2. 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
  3. At nights and weekends, do not switch ventilation off, but keep systems running at lower speed
  4. Ensure regular airing with windows (even in mechanically ventilated buildings)
  5. Keep toilet ventilation 24/7 in operation
  6. Avoid open windows in toilets to assure the right direction of ventilation
  7. Instruct building occupants to flush toilets with closed lid
  8. Switch air handling units with recirculation to 100% outdoor air
  9. Inspect heat recovery equipment to be sure that leakages are under control
  10. Switch fan coils either off or operate so that fans are continuously on
  11. Do not change heating, cooling and possible humidification setpoints
  12. Do not plan duct cleaning for this period
  13. Replace central outdoor air and extract air filters as usually, according to maintenance schedule
  14. Regular filter replacement and maintenance works shall be performed with common protective measures including respiratory protection.

Changes in our everyday lives can also be an incentive to change those habits and practices that affect the loss of biodiversity and impact climate change. We can start with ourselves, but at the same time it is essential that we also advocate for systemic change – only in this way will we be able to avoid a much more serious crisis in the future.