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The science of intelligent absorption

By Jürgen Mill

One of the fundamental dualities in the transportation industry is the balance between safety and comfort. At the core of every engineering and design concept there needs to be a consideration how something as visible as comfort can support something as important as safety—and vice versa.

To make things even more complicated, seat safety really is a catchall phrase that means a lot of different things to different stakeholders: Owners look for a seat’s compliance with various regulations and recommendations like the FMVSS 210 or 302. Recently, our customers in the bus and coach industry show an increased interest even in Docket A testing for flammability and smoke emissions, which used to be a common requirement for our clients in the rail sector only. Operational safety is most important for the driver and maintenance crew who need to be able to adjust, move, and clean seats easily. Similarly, bus builders prefer seats that can be installed without complicated and possibly dangerous lifting procedures. And of course, passengers of all sizes and mobility levels need to be able to rely on a seat made with fabrics that are inherently bacteria-resistant, seat backs and grab bars that are ergonomically designed to be kind to the spine and hands, and an overall design that will protect riders from injuries and whiplash in case of an impact.

Safer materials and engineering technologies are evolving constantly. Kiel for example, conducts extensive durability, fire safety and crash tests based on (among others) homologation standards to continually improve the safety and comfort of its products. A reputable seating provider should also have at its disposal a network of technically advanced, established R&D collaborators and a group of reliable, top-quality independent testing facilities.

Test dummies prepare themselves

Passengers of all sizes and mobility levels need to be able to rely on a seat’s safety.

The science of controlled plasticity

When safety and comfort form a perfect balance, the best seats create a protective survival space. This means that the seat is strong enough to withstand the forces of an impact but also flexible enough to absorb the energy of the impact intelligently. Based on numerous testing results over a long period of time, we have seen that the approach of “controlled plasticity” is the best protection against whiplash and other potentially serious injuries.

In order to comply with and/or exceed high North American safety standards, it is important to understand that one of the pillars of creating a robust-but-flexible seat is the use of high-grade materials that are extensively tested to exceed specific requirements. Within the context of controlled flexibility of materials, Kiel has been pioneering the integration of premium alloy metals like special engineered aluminums that will enter the state of plasticity more voluntarily and with minimal fractures compared to other commonly used metals with strengths of 700 millipascal and more. Obviously, a passenger in a seat in which everything gets bent just so slightly but in a controlled manner has a far better chance of escaping an impact unharmed than in a rigid, stiff “seat machine” that literally explodes uncontrollably.

In addition to the carefully engineered plasticity of materials, the seat’s upper-back section needs special attention as well when it comes to the integration of comfort and safety. A clean design that offers as little obstruction as possible in the area of the head and upper-seat back is of greatest importance since something as harmless as a coat hanger or grab bar can become a most dangerous force to the head in case of an accident. These accessories, as well as TVs and tablets, should be positioned on the side or well below the head level in the seat back.

Another small but important detail are edges. A minimum of 0.2 inches (or 5 millimeters) as a general rounding rule by which all edges are just slightly curved reduces injuries from components like tables and arm rests tremendously.

Lastly but just as important is a factor that is often overlooked: the utilization of skilled workmanship by a highly trained workforce. For Kiel, being able to oversee the entire manufacturing process from research and the initial design stages, to material sourcing, testing, and finally production has been a huge advantage. Employees who have learned their respective trades thoroughly, tend to take great pride in their quality craftsmanship and will give even the smallest details their utmost attention.


Jürgen Mill is senior VP of engineering and R&D at the global headquarters of the Kiel Group. Kiel is a trendsetting seat provider to transit systems around the world including seating solutions for buses and trains on the local, regional, and intercity level. Visit .

Posted by on May 1 2015. Filed under Features. You can follow any responses to this entry through the RSS 2.0. You can leave a response or trackback to this entry

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