Some high-performance plastics can be classified as flame resistant, non-flammable or self-extinguishing. This makes them suitable for use in fire protection. Standard and engineering thermoplastics are generally not flame retardant in the true sense of the word, as they begin to burn when exposed to direct flame. While most plastics continue to burn when the flame is removed, self-extinguishing plastics stop burning after a short time.
Thereby standard plastics like PE and PP as well as engineering plastics like POM, PA and PET are easily flammable. By modifications with flame retardants, a polyamide or polycarbonate, for example, can be made flame retardant, while high-performance plastics such as PVDF, PTFE, PPS, PEEK and PI are already self-extinguishing without modification.
There are various standards that classify the flammability of plastics: As a rule, the internationally recognised flammability test for plastics is carried out according to UL94. Furthermore, there are industry-specific flammability tests that define the flammability, burning behavior, smoke toxicity and other flammability properties of heat-resistant plastics. These specific flammability tests are intended to minimise the risks for fire causes and fire spread.
For rail vehicles, EN 45545 has uniformly regulated the fire protection requirements of all materials used throughout Europe since 2016. Depending on the application environment and hazard level, special testing requirements are placed on the material. Both our flame-retardant semi-finished polyamide PA 6 - TECAMID 6 FRT natural and the specially flame-retardant modified filament TECAFIL PC FR natural passed the requirement set R22 and R23 HL3 according to EN 45545-2:2016 for use in rail transport. Materials qualified to this standard can often pass more specific and stringent fire tests than required in other industry segments.
In the aerospace field, FAR 25.853 fire testing is critical. We have compiled details on the tests and our semi-finished plastic products and filaments tested according to FAR 25.853 for you on our page Plastics for Aerospace.
For automotive use, Federal Motor Vehicle Safety Standard FMVSS 302 (ISO 3795) is often required for materials to be used. Our products can be manufactured from raw materials that have been tested to this standard. If you have any further questions, please do not hesitate to contact our technical support team.
Most of Ensinger's technical data sheets contain information on the flammability according to UL94 of the material. Many of the raw materials we use are listed with UL94 and classified according to UL94 HB, V-1, V-2 or V-0. In some cases, flammability tests have been carried out directly on the plates or round bars of our semi-finished products in accordance with UL94. However, there is no listing at UL94 with Yellow Card. For further information or raw material Yellow Cards, please contact Ensinger's Application Engineering.
The classification of non-flammable plastics according to UL94 meets the following criteria:
The sample (a rectangular section of plastic of defined size) is held in a horizontal position and exposed to a direct flame at one end for 30 seconds. Then the flame is removed and the material must burn slower than a defined burn rate to be classified as HB.
The sample is held in a vertical position and exposed to a direct flame at the bottom for 10 seconds. After 10 repeated ignitions, the sum of the time required to stop burning after the flame is removed is taken. If the total extinguishing time is less than 50 seconds and no flaming droplets occur, the material can be classified as UL94 V-0.
The setup is the same as described above. If the total extinguishing time is less than 250 seconds and flaming drops occur, the material is classified as UL94 V-2.
