FT750

Fire Rating for Polyurethane Foams: There is a lot of confusion when discussing fire rated or Fire Retardant PU Foams. There is a clear distinction between these terms: Fire Rating means that a PU Foam has been tested with regards to its characteristics when exposed to fire; will it burn, how quickly will it burn, will it be self extinguishing, etc. In Europe, fire rating of building materials such as cured PU Foam is often expressed according to the German standard DIN 4102 part1. Fire Retardant means that a building material such as cured PU Foam has been tested in a specific configuration and the time during which this building materials prevents a fire from getting from one side of a wall to the other side of a wall is measured. fire rated PU Foams are not relevant when building safety is considered, it is the Fire Retardant characteristics of PU Foams which enhance the safety of a building in fire situations. What is DIN 4102? According to the German DIN 4102 (part 1) Building Materials are classified in Fire Rating A (non flammable building materials) which is sub classified in A1 and A2 and in Fire Rating B (flammable building materials) which is sub classified in B1, B2 and B3. B1 stands for "difficult flammability", B2 stands for "normal flammability" B3 stands for "easy flammability". These ratings refer to the actual flammability of the cured PU Foam. DIN 4102 defines the terms "flammability", the different test conditions and the instruments needed for testing etc. Without getting into details, the difference between DIN 4102 part 1 B2 and B3 ratings are as follows: 5 Samples of products (sealants, PU Foam, other building materials) are being prepared according to a certain set up and left to cure for 28 days . After complete curing the samples are set placed into a specified test gas burner and set alight in a specified way (distance of the flame, angle of the flame). The height of fire coming from the samples is measured during 15 seconds. If none of the ignited samples will reach a flame height of 150 mm, the product will get the fire rating B2, if even one single sample will exceed this height, the product will have the fire rating B3. Both B3 and B2 rated foams could, but need not be self extinguishing. Self extinguishing means that a flame coming from the gas burner is removed from the test sample the tested material will stop to burn and the fire will extinguish by itself. A product which meets DIN 4102 B1 must pass the B2 test and will then be exposed to a specific test in a fire shaft. In this test, 10 samples are tested and all need to pass. This test is done in specialized and approved test institutes according to the specific test methods set out in the standard.