The new version of UN regulation ECE R-118 applicable to bus production has further tightened the fire safety requirements for components installed in buses. Depending on their physical installation position in the vehicle, the bus seats, including upholstery and padding materials, must now not only meet the requirements stipulated for the horizontal burning rate (annex 6) but also pass a dripping test (Annex 7) as well as vertical burning rate tests (annex 8).
Standard upholstery materials available in the market do not always reliably meet the additional requirements set down in annexes 7 and 8 of ECE R-118. At first glance, conventional polyester non-wovens look like a valid alternative: Thanks to their high fire resistance and low density they are excellent and widely used insulation solutions for wall and ceiling areas in buses and rail vehicles. However, their restoring forces, which are important for ensuring durably comfortable upholstery, are not sufficient for seats that are in continuous use.
In cooperation with EvoBus, Cellofoam has now developed Cello® S400 - an innovative seat upholstery non-woven that scores on both counts, meeting the requirements of ECE R-118 as well as the bus industry’s expectations regarding comfort, long service life and easy handling.
Cello® S400 consists of a special polyester non-woven whose structural 3D elasticity makes for permanent high springiness in all directions. The material’s spring deflection characteristics correspond to the compression stress-strain curve of the previously used PUR foam and thus ensure simple and wrinkle-free installation. The excellent durability of the new Cello® S400 seat upholstery non-woven has been successfully confirmed in fatigue tests according to ISO 3358.
Compared to conventional PUR foams, the recyclable and breathable Cello® S400 offers a number of additional advantages: On top of higher ageing resistance and very good hydrolysis resistance, it scores with zero pollutant emissions and will not develop toxic smoke gases in the event of fire. Cello® S400 dries more quickly and, as the material does not allow any deposits to accumulate, also improves hygiene in the vehicle.
With Cello® S400, Cellofoam has succeeded in significantly enhancing the fire safety of bus seats while ensuring high seating comfort. Cello® S400 has proven its worth even in very demanding applications, e.g. on long-distance buses, and is now being used as standard in all Setra and Mercedes-Benz buses.