RCCN WeChat QrCode
Mobile WebSiteUL94 HB: horizontal burning
This plastic burns slowly but does not self-extinguish. This type is the lowest level of UL, and is often used when the vertical V0, V1 or V2 method does not work.
UL94 V0, V1, V2, V5: vertical combustion
The UL flame retardant classification system is as follows:
UL94 V0 evaluation method: After the flame is removed after ignition, the sample can be self-extinguishing to a melt that does not burn in a certain period of time (that is, the burning melt drops on the bottom of the test sample) On the cotton pad of the foot, the cotton cannot be ignited).
The UL94 V1 rating method is similar to V0 except that it requires a longer self-extinguishing time. This test allows the melt to drip onto the cotton mat but does not ignite the cotton.
UL94 V2 is the same as V1 except that it allows the burning droplets to ignite the cotton under one foot.
UL94 V5 is the most rigorous test method, which involves the actual life of plastic products in the flame. The experiment requires a flame length of 5 in, applying five times of combustion to the test sample, during which no droplets are allowed to drip, the test sample is not allowed to be significantly distorted, and no burnt holes are produced.
The UL 94 standard is the test method standard for the combustion properties of materials developed by Underwriters Laboratories. The UL 94 HB grade is the lowest level of the classification of material combustion performance in the UL 94 standard. The horizontal combustion test method is adopted. The standard is GB/T2408-1996 plastic combustion performance test method horizontal method and vertical method, "UL 94 HB grade" basically corresponds to China's GB/T2408-1996 FH3 grade, but also slightly different. From the current situation in China, the combustion performance of the material has reached "UL 94 HB grade" (FH3 grade of GB/T2408-1996 in China), it can be said that the material can hardly be said to have flame retardant properties.
