Better air in school buses 

The automotive supplier equips school buses in the USA with efficient HEPA H14 air filtration systems and minimizes the infection risk on the way to school.  

Gilching – October 06, 2022 – In the fight against Covid-19, companies and organizations around the world are using HEPA air filtration systems from Webasto. In the USA, the buses of the Prince George County School District in the US state of Virginia were most recently equipped with the HFT 300. The filters are used on a total of 119 bus routes.

Medical grade HEPA filters cannot be integrated into existing air conditioning systems on buses or other vehicles due to the extremely high pressure drop they require. However, the filter system from Webasto can be operated from a 12 Volt power source, independently of the bus air conditioning system. This simplifies and speeds up installation. In addition, the system can be mounted vertically or horizontally in the interior of the school bus, depending on the space available.

Highly effective filter system

The HFT 300 filter system is capable of removing particles smaller than 0.3 micrometers – including airborne viruses, bacteria, aerosols and dust – from five cubic meters of air per minute. It therefore complies with the requirements of HEPA filter class H14 and the guidelines of the World Health Organization (WHO), the US Center for Disease Control and Prevention (CDC) and of the European Centre for Disease Prevention and Control (ECDC). The degree of purification corresponds to 99.995 percent. The system therefore significantly reduces the risk of infection. The HFT 300 can be easily retrofitted to existing vehicles and is also suitable for use in other public transport or larger communal spaces such as doctors' surgeries and hotel lobbies.

The filters remove infectious agents from the air, which means that they become contaminated with potentially infectious and dangerous pathogens. It must therefore be possible to maintain and replace them in a manner that does not contaminate the vehicle or put service technicians at risk. To solve this challenge, the HFT is equipped with a special mechanism that hermetically seals the filter element before it is removed from the filter housing. Webasto’s HFT is the only filter on the market that allows the filter to be changed in such a safe, zero-contamination manner. Moreover, Webasto only uses the highest quality HEPA filtration grade – H14 – which is used, for example, for infection control purposes in medical facilities.

Not all filters are created equal

The efficiency of the filter system has also been confirmed by Dutch research organization TNO (Netherlands Organisation for Applied Scientific Research) in a study of particle concentration in two bus types (city and intercity bus) with different air filter technologies. The trial took place over a period of one hour. The results indicate that not every filter is effective. A passive HEPA filter alone had no effect on the recirculated air supply of the bus. Only a combination of return air and active filter units – as in the case of Webasto’s filter systems – was capable of significantly reducing particle concentrations after a short period of time.