Flammability class and reaction to fire
The reaction to fire class (flammability) of polyurethane foams is compliant with PN-EN 13501.
The reaction to fire class acc. to PN-EN 13501 is the Polish standard related to the response to fire and is aimed at specifying the flammability of construction products. The classification includes classes A1 and A2, which are the highest and best classes of the safest – non-flammable – products. Class B includes products with slightly worse parameters, where the products do not flash over during the reference RCT (Room Corner Test) test. Classes C, D and E include products which flash over under specific conditions and after a specific time. Class F is the lowest group, including flammable products for which no requirements are specified.
Polyurethane foams without enclosures usually belong to fire reaction classes D, E and F acc. to PN-EN 13501.
Polyurethane foams can also be classified by the German DIN 4102 standard. The test method measures the ignitability of construction products after exposing them to a small fire.
Polyurethane foams can be of class B2 or B3.
Class B2 – after exposing the foam to a small fire, the flame should be no higher than 15 cm.
Class B3 – the flame is higher than 15 cm.