UL94 standard in each level (where V0, V1, V2, HB) difference and authentication methods
UL certification is the floorboard of the underwriters experiments on various certification. UL authentication method about plastics combustibility has two kinds: one kind is we usually see most UL94 where V0, V1, V2, V5, this is a test of the vertical combustion method; Another is that we rarely see UL94 HB level, this is the method of the test.
UL94 HB: horizontal burning
The plastic can slowly but not self-extinguishing burning. This type is the lowest level of the UL, often with vertical where V0, V1 and V2 way doesn't work when using this method.
UL94 where V0, V1, V2, V5: vertical combustion
UL flame retardancy classification system is as follows:
UL94 where V0 assessment method: from after lighting the fire quickly self-extinguishing after samples to gap within a certain amount of time without burning melt dripping (that is, the burning melt dripping in the test samples under a foot of cotton mat, ignition cotton).
UL94 V1 assessment method is similar to where V0, but it requires self-extinguishing is some long time. This test allows the melt dripping in cotton mat, but can't light cotton.
UL94 V1 and V2 is the same, but it allows the burning will drop a foot of cotton under the light.
UL94 V5 is the most stringent testing method, which involves plastic products the actual in the flame of life. Flame length is 5 in the experiment requirement, the test samples on five combustion, during which there is no molten drops down, do not allow the test samples have obvious distortion, also does not produce any hole was burned out.
