Air Filtration and Purification Systems

Powerful, Proven Passenger Protection
A New Generation Of Effectiveness Always On Guard For You

Current cleaning methods help to reduce contagion spread when the train is out of service, but today you need more – especially during train operation, when the risk for contamination is present every time the train doors open and passengers enter and exit. You need a proven, effective, and highly-powerful ally in your fight … the 3-Stage Air Filtration & Purification System from Knorr Brake Company (KBC).

The only engineered solution available in the market, KBC’s technologically advanced patent-pending 3-stage air filtration and purification system – developed by Knorr-Bremse’s climate control division, Merak – is a unique and potent tool available on new builds and easily retrofittable into the HVAC unit on tramway/light rail, metro, regional, and intercity passenger vehicles.

Based on proven technologies, the 3-stage system removes or eliminates nearly 100% of airborne particulates, bacteria, and viruses – including COVID-19 – and outperforms any one of the stages alone.

A powerful technology designed to rapidly restore air quality in railway vehicles and drastically reduce any airborne concentration of aerosols and pathogens.

Today, testing and analysis supports the fact that one simple filter component is just not enough to eradicate virus, bacteria, and pollutants that circulate around us. That’s where the power of three interlocking barriers form your best defense.

  • First, the filtration process – via the MIFD (Merak Intense Field Dielectric)– uses physical filtration and electrostatic discharge to remove particles and reduce and halt virus transmission in the recirculated air.
  • Second, the potent purification process begins, directly inactivating organisms – eradicating them in the mixing plenum with UV-C radiation via the UVGI (Ultraviolet Germicidal Irradiation). The UVGI module is safely contained within the roof-mounted HVAC unit and therefore poses no risk of exposure to passengers or maintenance personnel.
  • Third, the purification process continues, fortifying the protection via the MDBD (Merak Dielectric Barrier Discharge) that ionizes the air as it is blown out into the ducting/train. The ions travel through the air and attack pollutants, remove particulates, and kill viruses and bacteria. The ions also travel deep through the air distribution ducts of the car and into the vehicle interior to provide purification on surfaces in the passenger area.

The three integrated modules of our state-of-the-art 3-Stage system work seamlessly to arrest and deactivate viruses and pollutants. And, with its technologically advanced design, the 3-Stage Air Filtration & Purification solution is a sustainable, eco-friendly system with zero secondary emissions, increasing your protection levels for passengers while you continue to decrease your impact on the environment.

Looking to enhance your HVAC system even more? Add-on accessories and services are also available from KBC for additional peace of mind, including system monitoring and in-car indicator devices to let passengers and crew members know the system is at work while the train is in operation; and mobile MIFD filter cleaning stations to help to safely handle and decontaminate filters during service.

Looking for a standalone air purification and filtration unit? Visit the Obsidian website .

When it comes to the safety of your riders, the best combination delivers the best results.



System Feature Function of the 3-Stage Air Filtration and Purification System
  • UVGI (Ultraviolet Germicidal Irradiation) that kills bacteria, mold, and virus
  • MDBD Air Purification removes floating bacteria, resolves pollutants, and reduces particulate matter 2.5
  • MIFD PM 2.5 Removal that arrests particles at close to 100% and delivers three essential functions in one: it prefilters, charges the particulates in the air, and offers particle arrest keeping charged particles in the inner surface of the MIFD Cell until it dies.
Provides comprehensive active and passive filtration and purification for your rolling stock 24/7/365
Self-contained within the HVAC system
  • Ease of integration and eliminates changes on the car side
  • The UVGI module poses no risk of UV exposure to passengers or maintenance personnel
Inter-operating efficiency The MDBD, MIFD, and UV-C has no negative impact on your HVAC system performance and will not impact heating and cooling capacity
The MIFD fits in the existing filter location, for comparable maintenance access and extended maintenance intervals There are no wearing parts and with extended intervals for filter cleaning and light inspection, you can focus your team on returning to safe, normal operation
UV-C bulbs are replaced at 12 months or 9,000 hours per standard UV-C established germicidal effect lifetime  
Lightweight @ 10 lbs Does not compromise train performance
Low power consumption and zero secondary pollution Enhance your carbon footprint with no ozone generation
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