1.1 This specification covers electric fusion welded pipe suitable for high-temperature or corrosive service as listed in Table 1. (Although no restrictions are placed on the sizes of pipe that may be furnished under this specification, This specification covers electric fusion welded pipe suitable for high-temperature or corrosive service. The pipes are designated into five classes namely Class 1, Class 2, Class 3, Class 4 and Class 5, according to how they are to be welded. The join