Flame retardance of plastics

Standard 94 of the Underwriters Laboratories (UL94) is accepted world-wide as the predominant standard for classifying the flame retardance of plastics. The procedure according to UL94 is to test the ability of the material to extinguish itself after flaming. The classification is according to the speed of burning and the extinguishing time, droplet formation, and the duration of afterglow time. Depending on the wall thickness, several classifications are possible for each material. The basis for the appropriate specification of a material should correspond to the thickness of the moulding’s main wall. Information on the UL 94 classification is only comparable and meaningful if it specifies the relevant wall thickness.