Keeping it clean: air sanitation for the rail industry

It’s also a topic that’s grown in importance due to Covid19, where it became intimately linked to passenger safety, and caused many rail companies to review their options:

• The good news here is that there’s a wide range of technologies to choose from
• The bad news is that many of these products are not able to deliver the quality and safety standards required

What doesn’t help is a general lack of universally recognized testing parameters for measuring performance. Which is why Thermo King continues to work with our customers to apply the industry’s most stringent test conditions, with a clear focus on safety, efficacy, and suitability.

Safety

It should always be kept in mind that certain air purification systems are not safe for human use. This is due to the chemical reactions that occur during their operation, which in turn can create harmful side products – such as ozone.

There exist numerous regulations surrounding these side products, such as UL2998, which demands that no more than 5 parts per billion of ozone are introduced by a unit. Yet in truth, many solutions struggle to address this ‘side product’ issue, making it difficult for rail customers to purchase with confidence.

At Thermo King however, we continue to perform a wide range of tests at our Prague ETC facility and specialized laboratories in USA, to ensure our products remain compliant – and have both the documentation and certification to prove it!

Efficacy

The challenge here relates once again to the lack of widely applicable and consistent standards for testing. A fact that often calls into question the performance claims made by various manufacturers.

For example, testing conditions can be compromised in three key areas, if:

• The test itself is performed in a small space, which makes it easier to demonstrate high cleaning efficiency
• The selection of micro-organisms to test for is restricted, thereby making it easier to pass
• The testing environment is limited in terms of air flow, air velocity, and temperature – which can also lead to unrealistic results

Suitability

As already mentioned, any HVAC unit has to work within the space constraints of a client’s carriage design – which makes size and weight important considerations. Similarly, air flow and pressure drop also need to be optimized, with the unit and filter expected to have minimal impact on both.

To these factors can also be added other tests performed by Thermo King to ensure:

• The reliability and durability of each product
• Compliance with all regulatory standards
• Performance across a wide range of usage scenarios (including trams, trains, and different passenger ‘loads’)

Leading the way

So, what makes Thermo King technologies stand out from the pack? Well, to answer that we’d first highlight three particular areas:

• Our exceptionally rigorous testing focuses on the key parameters of virus removal and air quality, and is supported by a large team of experts – including a panel of external specialists who are regularly brought in to add their insight
• Thermo King products use graphene enhanced photocatalytic oxidation (GPCO) technology to inactivate viruses and other harmful microbes – while also removing odors and smells such as tobacco smoke
• Each unit is also designed for long operating lives and extremely low maintenance, which means greatly reduced operating costs when compared to other technologies such as UVC lamps or HEPA filters

In addition, Thermo King is also at the cutting edge when it comes to research and development.

For example:

• We’ve just completed testing a GPCO module for VOCs (volatile organic compounds) to be used exclusively in rail (with metal components replacing plastic parts for improved fire safety)
• For our UVC air sanitation products, Thermo King has also been testing for material degradation over time – to ensure these products can enjoy the longest possible working life in context to a rail carriage environment
• We’re also collaborating with filter producers to test new anti-bacterial surfaces that contain innovative fiber structures for air purification to aid performance in relation to pressure drops – while also making them even safer to maintain

Building confidence

Every rail customer has their own unique requirements for air sanitation. This is due largely to the fact that every project involves bespoke designs for rail carriages, and therefore the need for highly tailored solutions. Thermo King continues to work closely with customers to deliver safe, efficient, and high performing HVAC technologies – and our track record speaks for itself.