Flame retardant plastic

Some high performance plastics can be classified as flame resistant plastic, flame retardant plastic, non flammable plastic or inherently self extinguishing, making them suitable for use where fire protection is an issue. Thermoplastic materials, in general, are not properly flameproof in the real sense of term, because if exposed to direct flame they start to burn. But while most of plastics, once you remove the flame, continue burning, self-extinguishing plastics stop burning autonomously after a while. There are various standards which classify the flammability of plastics: normally, the internationally accepted flammability test for plastics described in UL94 is performed. 

Recently, the new European standard for fire protection on railway vehicles EN-45545 is also becoming popular, because it classifies both fire behavior and smoke emissions. Materials that are qualified according to this standard can often successfully pass also more specific and severe fire tests that are required in other industrial segments (e.g. FAR 25.853 for aerospace).

There are also industry-specific flammability tests which define the combustion behavior, flue gas toxicity and other flammability properties of heat-resistant plastics. These special flammability tests are designed to minimize the risks of causing and spreading of fires.

In the field of aviation, the fire test according to FAR 25.853 is of significant importance.Information on the tests of our plastic semi-finished products,tested in accordance with FAR 25.853, can be found on the page aircraft interior plastics.

Since 2016, EN 45545 has uniformly regulated the fire protection requirements of all materials used for rail vehicles throughout Europe. Depending on the application, environment and hazard level, a special test requirement is placed on the material. The polyamide PA 6 - TECAMID 6 FRT natural has been tested in accordance with EN 45545-2:2016 for use in rail traffic.

For automotive applications, the Federal Motor Vehicle Safety Standard FMVSS 302 (ISO 3795) is often required in order to use materials. In many cases, our semi-finished plastic products are manufactured from raw materials that have been tested according to this standard. If you have any further questions, please do not hesitate to contact our technical service department.

Most of Ensinger's material technical datasheets contain information regarding the material's UL94 rating. Some of our materials are tested to verify their compliance with the requirements of the respective UL classification but are not Yellow Card certified. For additional information, please contact Ensinger Technical Services.

Flame resistant plastics according to UL94

Classification of flame resistant plastics according to UL94 follows these criteria:

UL94 HB plastic (horizontal burning):
The specimen (a rectangular plastic strip of defined size) is held in horizontal position and is exposed for 30 seconds to direct flame on one end. Then the flame is removed, and the material must burn slower than a defined burning speed to be classified as HB.

UL94 V-0 plastic (vertical burning): 

The specimen is held in vertical position and is exposed for 10 seconds to direct flame on the bottom end. After 10 repeated ignitions, the sum of the time needed to stop burning after the removal of the flame is made. If the total extinguishing time is below 50 seconds and no flaming drips occur, the material can be classified as UL94 V-0.

UL94 V-2 plastic (vertical burning): 

The setup is the same as described above. If the total extinguishing time is below 250 seconds and flaming drips occur, the material is classified as UL94 V-2.

UL94 V-1 plastic (vertical burning): 

The setup is the same as described above. If the total extinguishing time is below 250 seconds and no flaming drips occur, the material is classified as UL94 V-1.