What is UL94 HB rating?
What is UL94 HB rating? H-B Horizontal Burn Slow horizontal burning on a 3mm thick specimen with a burning rate is less than 3”/min or stops burning before the 5” mark. H-B rated materials are considered “self-extinguishing”. This is the lowest (least flame retardant) UL94 rating. What is HB flammability rating? UL 94 Classification and Flame-Retardant ThermoplasticsUL 94 RatingDefinition of RatingHBSlow burning on a horizontal partV-2Burning stops within 30 seconds on a part allowing for drops of vertical flammable plastic. What does flammability rating mean? The horizontal burning test is used to determine the HB flammability rating of a material....