MAYENCE, Germany | Ventilate to reduce the risk of transmission of COVID-19, not so easy in winter. A German school thinks it has found an ingenious alternative that is accessible to all amateur DIY enthusiasts.
The idea: a “homemade” system to suck the aerosols over the heads of each pupil, tested at the IGS Mainz-Brentzenheim high school, in Mainz (west).
“It works like a kitchen hood,” explains Frank Helleis, scientist and husband of a school teacher, in the classroom equipped with his invention.
With this installation, the classroom almost takes on the appearance of a special shuttle: above each table hangs a plastic dish. It captures the hot air exhaled by the students, which rises above the heads. Narrow pipes lead it, with any dangerous aerosols, into a large main tube.
From there, a fan connected to a window expels everything outside. Fresh air can enter through a second, ajar window.
Initial measurements carried out by the prestigious Max Planck Institute for Chemistry, where Mr. Helleis works, showed that the system could rid the classroom of more than 90% of aerosols, which is as much as the most efficient and expensive filters on the market. .
But unlike these machines, Mr. Helleis’ installation is made entirely from parts available in DIY stores and costs only 200 euros.
Better yet: a handful of teachers and parents put it together in one morning.
The plans are now available to everyone on the Max Planck Institute website.
Pullover in reserve
The innovation arrives on time: the first frosts are here while the figures for new contaminations are breaking records in Germany. The country has closed restaurants, bars and places of leisure until the end of the month, but schools remain open.
Along with the rules of physical distancing and the wearing of masks, regular ventilation of closed spaces is one of the government’s mantras.
Chancellor Angela Merkel herself regularly reminds her fellow citizens to open the windows.
Like Sophia Wetting, 18, some students therefore keep an extra sweater in their lockers. Masked like her comrades and teachers, she finds the lessons in the futuristic classroom “much nicer” than elsewhere.
Mr. Helleis has already received some 3,000 requests for information about his invention and expects it to multiply in other schools. Companies are also interested.
Inspiration came from a simple idea. “We said to ourselves: the thing we can do is put the dirt outside,” recalls the scientist.
Roland Wollowski, the director of the high school – located five minutes from the headquarters of the company BioNTech, which is developing the most advanced vaccine against COVID-19 – immediately gave his approval.
Purify the air, a market
The German Environment Agency recommends that German schools open windows every 20 minutes to reduce the risk of aerosol contamination.
But the 40,000 schools in the country are not all equipped with an architecture that allows it. And installing air purifiers remains a complex and expensive option in a market that has exploded with the pandemic.
“We are inundated” by companies offering their products, explains Heinz-Peter Meidinger, president of the national teachers’ federation.
The price of a device: between 1500 and 6000 euros.
Of the sixteen German Länder, six have earmarked funds to finance installations improving ventilation.
In Bavaria, the regional government has released a budget of 50 million euros. Some of it, however, according to Meidinger, should be used for less advanced tools, which measure CO2 concentration and let teachers know it’s time to open the windows.
Portable air purifiers, even with high-performance filters, do not prevent CO2, responsible for fatigue and headaches, from accumulating, notes Mr. Helleis – in addition to being more expensive and noisy than his invention.
At Mr. Wollowski’s IGS Mainz-Brentzenheim, parents, teachers and students will be installing them in all rooms in the coming weeks.
“Everyone is very motivated,” enthuses the director.