COVID 19 : HEPA filters against virus infection risk

HEPA filters for mobile air purifiers and HVAC systems to minimise the risk of SARS‐CoV‐2 infections.

People spend most of their lives indoor, especially during the cold winter months. The COVID 19 pandemic increases the focus on minimising the risk of infection, also indoors, via indoor air quality. EMW filtertechnik offers manufacturers and users of mobile room air conditioning units and HVAC systems suitable HEPA filters of the HEPA filter classes H13 and H14. In addition to standard solutions, we can also offer newly developed filter solutions to ensure that your existing ventilation concept complies with the current needs.

What must be considered when designing filter systems for air purifiers?

The current corona pandemic requires a rethinking of the current practice for assessing indoor air quality. To reduce the probability of infection, high air exchange rates must be achieved. Ventilation increases the propor on of fresh air, but high air exchange rates are necessar to effectively reduce the infection risk. In cold periods, this approach affects the energy balance and the climatic feel‐good atmosphere of an interior. In addition, a potentially existing virus concentration can rise again after closing the windows.

Requirements for air purifiers in times of the corona pandemic.

Air purifier can ensure a permanent reduction of the risk of infection. According to a study by the German Armed Forces University in Munich[1], room air conditioning filters can minimise the risk of infection from COVID‐19 more efficiently than continuous ventilation. Away from hospitals etc., however, room air conditioning filters with a separation function in the HEPA area have rarely been required for rooms in the past. In case of doubt, common filter solutions are not efficient enough to counter the risk of COVID‐19 infection. The corona pandemic makes it clear that indoor air quality should be cleaned with air conditioning filter systems of the HEPA filter classes.

According to a study by the Goethe University in Frankfurt a.M.[2], mobile air purifiers with HEPA air filters can help to reduce the virus concentration by 90 percent within half an hour. If there is a super‐spreader in the room, mobile air purifiers reduce the risk of infection, according to the scientists at the Goethe University. To this end, the following requirements must be met by mobile room air conditioning systems:

  • A mobile room air conditioning unit should be able to filter six times the room volume. For a room with approx. 85m² and a wall hight of 3m, therefore, approx. 1500 cubic metres of air per hour must be filtered.
  • The filter system should include HEPA air filters with filter class H13 or H14 to achieve a separation efficiency of ≥99.95% or ≥99.995% for the relevant particle spectrum with a diameter of <0.3 µm.
  • The unit should be able to operate as quietly as possible. Here, the air filters influence the noise pollution through their design and the pressure difference generated.

[1]: Kähler, C. et al (2020): Können mobile Raumluftreiniger eine indirekte SARS-CoV-2 Infektionsgefahr durch Aerosole wirksam reduzieren?

[2]: Curtius, J. et al (2020): Testing mobile air purifiers in a school classroom: Reducing the airborne transmission risk for SARS-CoV-2.

Our filter solutions vs. COVID‐19

EMW offers a range of HEPA air filters to minimise the risk of infection by viruses such as SARS‐CoV‐ 2. SARS‐CoV‐2 is also transmitted via aerosols which can be assigned to the size of a few hundreds of nanometers. Depending on the required air exchange rate, the HEPA filters must be designed in such a way that the physical filtration effects for particle separation can also be effective at higher volume flows. In addition, the filter solutions for air purifiers must also be designed with regard to efficient energy consumption and low noise pollution. EMW offers you a range ofHEPA filters for your existing filter system of mobile air purifiers and HVAC systems. We can also provide you with tailor‐made HEPA filter solutions which are optimally tailored to the specific requirements of air purifiers and HVAC systems .

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