The UL 94 fire test is an internationally recognized test standard developed by Underwriters Laboratories (UL). It is used to evaluate the flammability of plastics. Various properties of the material are tested under defined fire conditions to determine how it behaves when exposed to fire. This classification is important for the selection of materials in applications where fire resistance plays a crucial role, such as in the electronics or automotive industries. The test typically involves examining samples in the form of rods or plates that are exposed to a specific flame in a vertical or horizontal setup. The fire behavior is assessed based on various criteria such as flame spread, droplet formation, afterglow and self-extinguishing.
Based on the test results, the materials are divided into different classes, including UL 94 V-0, UL 94 V-1 and UL 94 V-2, where V stands for vertical. The UL 94 HB test is also common, which specifies a horizontal test of the test bars and determination of the burning rate.
