Redesigned filter system for air purifiers

We had to reassess the required standards for indoor air quality in the times of the corona virus pandemic. To reduce probability of infection, high exchange rates must be achieved. Air purifiers can ensure the risk of infection is permanent reduced.

According to a study by the Goethe University in Frankfurt ^[1], air purifiers with HEPA air filters can help to reduce the virus concentration by 90 percent within half an hour. If there is an infected person in the room, mobile air purifiers reduce the risk of infection, according to the scientists at the Goethe University. 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 height of 3m, therefore, approx. 1500 cubic meters 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]: Curtius, J. et al (2020): Testing mobile air purifiers in a school classroom: Reducing the airborne transmission risk for SARS-CoV-2.