A "How To" guide on Fixing Pipelines

The Pipeline Research Council International (PRCI) recently issued an updated copy of its Pipeline Repair Manual, originally published in 1994. The updated manual discusses response to anomaly or defect discovery, reviews repair methods, identifies appropriate repairs for various types of defects, and provides generic guidelines for use of various repair methods. The updated manual was prepared by DNV/CC Technologies and Edison Welding Institute as research agencies for PRCI.

This manual should probably be required reading for all pipeline operators and engineers who practice this fine profession. It could very well be integrated and used as a fundamental part of every operator’s operation, inspection, and maintenance manual. While the PRCI manual does not identify or prescribe all repair methods for all defects or anomalies, it concentrates on commonly encountered defects and commonly used methodologies. What you do to fix your pipeline may be equally valid depending on the specific conditions encountered. This updated manual helps provide a “sanity or reality check” for how other operators successfully do their pipeline repairs.

The revised manual contains added and updated information on repair technologies from published literature, vendor publications, and survey of industry experience. Existing and emerging pipeline repair methodologies were evaluated in comparison with those in the earlier version of the manual. The section on weld deposition repair and welding on in-service pipelines was revised based upon extensive research conducted by the Edison Welding Institute.

The document is available in hard copy and electronic formats. It can be searched for rapid location of information on a specific topic. The revised manual does not provide guidance on current regulations or on code interpretation due to the evolution of regulatory and code compliance situations. Footnotes are included to identify specific sections of selected U.S. regulations, however.

The manual initially covers response to the discovery of an anomaly or defect. This part addresses pressure reduction concerns from leak surveys, in-line inspections, hydrotest pressure failures, and other such pressure-reduction considerations. Excavation safety is part of this response discussion. Details are included concerning critical information for repair decisions such as pipe material, pipeline operating characteristics, pipeline configuration and location, and nature and extent of anomaly. Also addressed are considerations for repair materials and personnel, along with inherent risk in performing repairs.

It also provides focus on various pipeline repair methods. These include removal and replacement of a defective segment, grinding, full-encirclement sleeves and special sleeve configurations. These include Type A reinforcing sleeves and Type B sleeves for pressure containing (or capable of containing pressure). Other sleeve types addressed include sleeves to repair couplings, sleeve-on-sleeve repairs, and sleeve configurations for curved, field-bent pipe. Composite reinforcement sleeves and weld deposition repairs are also covered in detail. Mechanical clamps, hot tapping, and patches or half soles are also reviewed.

The manual also addresses appropriate repairs for various types of defects, including an overview of repair applications. Guidelines for repair procedures are identified. For specifying repairs to particular defects, detailed selection criteria is reviewed for the following:

• External corrosion
• Internal corrosion
• Plain dents or dents with stress concentrators
• Longitudinal cracks and arc burns
• Girth-weld defects
• Wrinkle bends and buckles
• Hard spots
• Blisters and HIC
• Couplings
• Defective prior repairs.

Proprietary repair systems are illustrated in the manual with system information from Clock Spring, Armor Plate, Allen Edwards, WrapMaster, and T.D. Williamson, in addition to the generic systems supplied by various manufacturers.