New switch cabinet seal from Sonderhoff fulfils UL 94 HF-1

New switch cabinet seal from Sonderhoff fulfils UL 94 HF-1 (PresseBox) (Köln, ) The latest development from Sonderhoff Chemicals, the flameproof polyurethane foam seal Fermapor® K31-A-45C4-2-UL-FR, complies with US fire protection standard UL 94 HF-1. The seal also has a UL listing for US testing standard UL 50E for switch cabinets and electronic housings in non-explosion-proof areas, in addition to UL 508, the US specification for electric switchgear safety.

As the independent organisation "Underwriter Laboratories" recently confirmed to Sonderhoff, the new polyurethane foam seal Fermapor® K31-A-45C4-2-UL-FR passed the testing criteria for UL 94 HF-1 for fire protection and has been registered as "UL-recognised". This listing can be seen on the UL website

During single part tests for the UL 94 HF-1, the property profile for the new polyurethane foam seal was investigated under the application conditions specified by the UL. The flameproof Fermapor® K31 foam seal can therefore be used for the sealing of switch cabinets and electronic housings made of metal or plastic in application locations where the stringent US fire protection regulations apply.

Fermapor® K31-A-45C4-2-UL-FR, with its "HF-1" UL class, achieved the highest fire protection class for polyurethane foams. The polyurethane foam seal from Sonderhoff is therefore classified as self-extinguishing without burning drips, which could otherwise cause their own fire, in accordance with UL94 HF-1.

The UL 94, a test specification for the assessment of fire properties in polymer materials is one of the most important requirements for the sales of electrical appliances and other electronic applications in the USA, Canada and Mexico.


Sonderhoff Holding GmbH
Richard-Byrd-Straße 24
D-50829 Köln
Florian Kampf
Teamleiter Marketing


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