overview of fr materials
— fr materials (fire retardant materials) are classified based on ul 94 flame classifications of each material. there are 6 flame classifications specified in ul 94 that are assigned to materials based on the results of these small-scale flame tests. these classifications listed in descending order for each of the following three groupings are used to distinguish a material's burning characteristics after test specimens have been exposed to a specified test flame under controlled laboratory conditions. these classifications relate to materials commonly used in manufacturing enclosures, structural parts and insulators found in consumer electronic products (ul 94 5va, 5vb, v-0, v-1, v-2, hb).
for more details, see:ul flame classifications for plastics