Ventilation systems with energy-saving features must be installed in schools and kindergartens.

Fresh filtered air largely helps prevent the spread of Covid-19

As every year, this year too, the school year began on September 15 in Bulgarian schools. In the past weeks, all parents, children, and teachers have been busy preparing for the first day of school. The media continuously debated whether children should wear masks at school, what measures would be in place, and whether children would attend classes in person or remotely. This is the new reality we live in, and we all hope it will end soon. Nevertheless, society will continue to be highly sensitive to viruses and illnesses.

Scientists from Imperial College London demonstrated earlier this year that measures to improve indoor air quality are as effective as social distancing and protective masks. Their study showed that droplets (aerosols) exhaled in an enclosed space can remain active for up to 16 hours. At the beginning of the SARS-CoV-2 pandemic, everyone thought the virus was heavy and that infection occurred from fallen droplets (fomites) or by being close to an infected person without a protective mask. Today, it is clear to everyone that COVID-19, especially the Delta variant, is transmitted through airborne aerosols. For this reason, all experts and health authorities in Europe and the USA recommend using ventilation systems to exchange air indoors to reduce virus spread. These systems lead to better indoor climate, lower energy costs, and most importantly – healthier occupants. The money invested in prevention is many times less than what must later be spent on medicines and treatment.

The European Federation for Ventilation, Air Conditioning, and Heating has published a guide for preventing the spread of Covid-19 in schools and kindergartens. The main recommendations relate to recuperative ventilation, the amount of fresh air, and air filtration in these spaces. Unfortunately, in Bulgaria, there are almost no schools or kindergartens with effective ventilation systems installed.

In the UK (The Royal Society of Medicine) and Germany (the Robert Koch Institute), the use of ventilation devices with HEPA filters is recommended in cases where general ventilation systems are not installed. „To keep schools and kindergartens open, there is an urgent need to implement more effective strategies to reduce aerosol transmission of the virus and to pay special attention to ventilation“ , say scientists from the National Heart and Lung Institute at Imperial College London.

At the end of 2020, a British journalist from the BBC (Jenny Hill) conducted an investigation and made a short film to show how federal municipalities in Germany are dealing with technical problems and finding solutions for air purification in school classrooms.

The German government is investing 500 million euros to improve ventilation systems in public buildings to help stop the spread of the coronavirus. The grant funds are intended to upgrade ventilation systems in public offices, museums and theaters, universities, and schools. The German federal government requires schools without ventilation systems to receive at least mobile air purifiers, which must ensure purification with HEPA filters and be certified by an independent organization.

An article in the British publication ‘The Guardian’ quotes the German Chancellor, Ms. Angela Merkel, saying that ventilation is perhaps the cheapest and most effective solution for dealing with the virus.

In mid-August 2021, the Dutch government announced an emergency plan to invest 100 million euros by the end of the year and another 260 million euros over the next two years to ensure in-person education for all children in schools and kindergartens. The Minister of Education, Arie Slob, stated that improving the indoor climate in educational institutions will help reduce the spread not only of the coronavirus Covid-19 but also of other illnesses, asthma, and allergies.

A study by the European Centre for Disease Prevention and Control shows that if a teacher infected with Covid-19 enters a classroom with 24 students, they would infect between four and eight students during one lesson. If the same classroom uses a fresh air ventilation system, the number of infected students would be only one or two.

Opening windows in classrooms is a solution to the issue of fresh air and ventilation, but it leads to very high heating costs and significant discomfort. Additionally, cold air during winter is not beneficial for children. Based on experience from installed recuperative ventilation systems in the Czech Republic, Poland, and Portugal, we have data showing heating costs could be around 30-35% lower. At the same time, air quality sensors indicate an incomparably better indoor climate in rooms equipped with energy-saving ventilation.

To meet the requirements of our partners in Europe, we have developed two types of solutions for ventilation and air purification in schools and kindergartens:

1. Energy-saving ventilation with air filtration that can be installed in place of an existing radiator in the room or in a corner near an exterior wall. The device provides a decentralized solution that filters fresh air, heats it, and supplies it to the children while simultaneously extracting and expelling polluted air.
2. The second solution is a standalone device for cold air sterilization, which does not require ventilation. The unit draws in polluted air, purifies it through a two-stage filtration system with a HEPA filter, and then irradiates it with UV-C rays to ensure the elimination of Covid-19 pathogens.

The systems manufactured by 'TANGRA – AV' Ltd. comply with all the recommendations of the HVAC association Eurovent, as well as the European Federation for Ventilation, Air Conditioning, and Heating – REHVA. The equipment is certified by Eurovent Certita Certification and VOSTOX.