Vertical ventilation concept reduces virus load in enclosed spaces

Oberpfaffenhofen, Germany. With a design for an effective filter system for enclosed spaces, OHB System AG, a subsidiary of German aerospace and technology group OHB SE, and the HT Group, a specialist in outfitting operating theaters, laboratories and hospital wards, want to make a contribution to curbing the coronavirus: The “Next-Generation Class Room” is a retrofit kit for reducing virus intensity (corona and influenza viruses) and, hence, the risk of infection in rooms.

“Using a vertical ventilation concept, we want to quickly filter air that is potentially virus-contaminated and prevent uncontrolled mixing of the air in the room,” explains Dr. Axel Müller, a cleanliness expert at OHB System AG. Major structural conversion measures are not necessary for the installation of the retrofit kit.

The rising air stream protects people in the vicinity

The gentle, slow-moving filtered airflow is introduced at the bottom of the room and, due to the human-induced uplifting effect, flows upwards past the people in the room towards the ceiling. A directed undisturbed airflow arises between the person’s head as the source of aerosols and the extraction device on the ceiling. This effect is aided by the fact that exhaled air is warmer than the ambient air. “With the OHB-HT concept, the heated, rising air and the filtered air introduced into the room move upwards simultaneously. This significantly reduces the horizontal distribution of air to the adjacent person, creating a protective wall of ultrapure air, so to speak,” explains Dr. Müller.

With the HT Group for more than 25 years, Thomas Fritsch is responsible for the construction of operating theaters and high-security laboratories: “The method we have chosen is the result of the HT Group’s decades of experience in filter and ventilation systems used in hygiene areas to produce low-germ air.”

Concept confirmed in scientific measurement campaign

The Institute of Aerodynamics and Flow Technology at the German Aerospace Center (DLR) in Göttingen can draw on more than ten years of expertise in ventilation systems. Dr. Andreas Westhoff oversaw the first multiday phase of the measurement campaign: “The examination of the OHB-HT room ventilation system has shown that the tested prototype can be used to create a stable flow leading from the human body directly to the extraction unit. The uplifting effect generated by the people in the room supports this effect. This reduces the uncontrolled spread of virus- and bacteria-contaminated aerosols from exhaled air. In addition, the virus-contaminated air is effectively fed into the filter system.” 

“We simulated a classroom, a waiting room, a catering area and cinema seating. The proportion of fresh air in the facial area and the removal of used air measured in the various constellations shows that the risk to the adjacent person was greatly reduced,” reports Axel Müller. The syndicate is planning to perform a practical test in a school or restaurant.

The “Next-Generation Class Room” syndicate

As a space systems specialist, OHB System AG forms the backbone with respect to coordinating the implementation of the project as well as simulation, design and experimental verification activities. With its expertise in designing and constructing ventilation systems for laboratories, hospital wards and operating theaters, the HT Group has extensive practical skills and the human resources required for implementing the OHB-HT system on site.A supplier of clean room textiles and a specialist in textile design and the associated production chain, DASTEX has already implemented clean room enclosures, air distribution systems and the like with and for OHB.