What does 94v0 mean on the FR4 94v0 board? We often see UL flame retardant plastics. 94v0, what does that mean? In the United States, UL certification managed by UL is usually a series of certifications. There are two ways for UL certification to burn Plastics: one is that we usually see UL dashes in the front.FR4 94v0 circuit board: 94v0, V1, V2, V5, which is the vertical combustion test method; the other one is usually not consistent with UL94 Hb, which is the level of the test method. UL94 HB: horizontal burning this plastic burns slowly but does not extinguish itself. This type is the lowest level of UL and usually does not work when using vertical V0, V1, or V2 methods.UL94V0: vertical flame UL flammability classification system is as follows: UL94V0 evaluation method: after the flame is removed from the flame, the sample can quickly self extinguish within a certain time interval, without burning droplets (that is, the burning droplets are in the burning state). The cotton pad one foot below the test sample will not ignite the cotton).