Fire resistance rating HB
In the horizontal fire test, the material burns slowly. During this, the burn speed may not exceed 3 inches/min up to a wall thickness of 3 mm and 1.5 inches /min with a wall thickness of above 3 mm. Materials which exceed these limit values for burn speed will not be registered by UL.
Fire resistance rating V2
In the vertical fire test, the fire must extinguish of its own accord after an average of 25 seconds (individual cases not more than 30 seconds). Burning drops from the material may ignite cotton wool placed under it. It may not smoulder for longer than 60 seconds.
Fire resistance rating V1
In the vertical fire test, likewise the fire must extinguish of its own accord after an average of 25 seconds (individual cases not more than 30 seconds). On the other hand, any burning drops must not ignite the cotton wool. Smouldering must have ceased after 30 seconds.
Fire resistance rating V0
In the vertical fire test, the fire must extinguish of its own accord in less than 5 seconds (individual cases not more than 10 seconds). Any burning drops must not ignite the cotton wool and smouldering must have ceased after 30 seconds.
