Prefabrication and Installation of Bends and Elbows for Long Distance Pipeline

Prefabrication and installation of elbows and bends for long distance pipeline may encounter such problems as considerable offset, big deviation of bending angle, variation of material properties during welding due to improper bend cutting, and deformation or damage undertaking during service. It is pointed out that care shall be taken from design to construction to every turning point over the line and elbows and bends prefabricated accodingly. Straight sections of proper length shall be reserved during prefabrication at both ends of the elbows and bends. Every elbow or bend shall be installed in its own place with no need for cutting. When bending pipes of longitudinal weld, the weld shall be positioned along the natural axial line, or, if the pipe has a girth weld, with a 30°cross angle with the natural axial.