... B 31.8 The insulation joint consists of structure parts, insulating ring, filling material, sealing ring and short tube. ... welding without any usage of bolt or flange. The insulating material and the seal ring are fixed in structural ... pressure, pipeline operating pressure and hydrostatic test. Insulating capacity: (by 1000v megohm meter) insulating resistance: ≥10MΩ, Breakdown voltage: ≥3KV.Life ...