FST performance is key.
We achieve HL3.


Today’s train operators and manufacturers are challenged by the need for even lighter, more energy-efficient and environmentally friendly trains without compromising safety and durability.

With ArmaForm Core we offer the railway industry a polyethylene terephthalate (PET) based structural foam core combining high strength to low weight, excellent fatigue and durability, superior temperature stability and excellent compatibility with all common resins and manufacturing methods.


Beyond the mechanical properties of sandwich structures used in railway applications, the fire smoke and toxicity (FST) performance is a top priority in public transport, even more when trains operate in underground or in tunnels. With the introduction of the new European standard EN 45545-2, the requirements for FST performance in core material have become even more demanding.

One of the big advantages of ArmaForm Core is the very low smoke and toxicity level achieved when subjected to fire. Armacell offers two grades, the non-self-extinguishing standard grade PET GR and the fire-retarded grade PET GFR. Experience in the industry has shown that fire-retarded core material grades are not necessarily needed for trains classified under EN 45545-2. The core material contributes mostly to the smoke and toxicity levels, slightly to heat release but almost not at all to flame spread, while the skins handle the flame response.

Official testing has shown that ArmaForm Core based sandwich structures, in combination with appropriate laminates, achieve the highest classification, HL3, which qualifies the material for use in all types of trains including metro, sleeper and couchette cars.

Today, designing and manufacturing eco-friendly trains also implies consideration of how the processed materials are manufactured. The use of ArmaForm Core, made from 100% post-consumer PET, enables Armacell and its customers to present a real 'green' alternative to standard PET foams and other foam core materials currently used in railway applications. A comprehensive LCA study has shown that ArmaForm Core PET GR outperforms any other foam core currently available on the composite market in terms of its environmental benefits.

CO2 emission savings during the ArmaForm Core foaming process: 


The ideal combination of superior FST properties, mechanical properties, cost-effectiveness and environmental sensitivity make ArmaForm Core the material of choice for railway sandwich applications such as component floor panels, nose cones, interior ceiling and partition walls, doors and much more.


Application: Body Structure / Interior / Door