The overall goal of this project was to develop practical guidelines for using segmented induction bends and long-radius (3D) elbows for pipeline construction and to identify practices which should be avoided. The scope of this project was limited to large diameter pipelines (e.g., 30 inch diameter and above), as the challenges to achieving proper fit-up and ultimately acceptable weld quality are complicated by such factors as ovality.
The need to use segmented induction bends and elbows can arise for a variety of reasons during construction of new pipelines or during pipeline repair and maintenance activities. Bends having a tighter radius than can be accomplished by cold field bending may be required to accommodate abrupt directional changes. While some tight-radius directional changes can be accommodated by ordering induction bends with specific bend angles, the specific bend angles required are not always known prior to construction. Therefore, the use of segmentable induction bends and elbows may also be required during pipeline repair activities.
This report describes the first of three phases of work, with each phase addressing a specific objective developed by the nine project participants. The first objective was to develop guidance regarding the specification and purchase of segmentable induction bends and elbows. The second objective was to develop guidance for field construction practices. The third objective was to evaluate the use of in-line caliper and deformation tool data to identify areas of concern in existing pipelines. This report pertains to the first objective only.