Improved In-field Welding and Coating Protocols

Overview

Main Objective

To reduce premature coating failures of in-field welded and coated pipeline sections/appurtenances. GTI/EWI will survey/summarize current in-field welding/coating practices and interactions and develop protocols to improve welding-coating coordination. GTI/EWI and partners will weld and coat test sections using the existing and improved protocols and validate improvements with accelerated corrosion/coating tests. A set of clear/concise recommendations will be submitted for incorporation into consensus guides and recommended practices (NACE/SSPC/AWS/API/AGA).

Public Abstract

During pipeline construction, a protective coating is applied to the weld joints after the welds are completed and inspected. The ability of the pipeline to resist corrosion depends on the quality of the welds and the integrity of the coating system. Welding factors that affect coating integrity include weld geometry (cap height and reinforcement angle (i.e., the intersecting angle between the weld cap and the pipe surface at the weld toe)) and hydrogen diffusion. In addition, during the installation of appurtenances (e.g., hot tap branch connections and repair devices, including full-encirclement sleeves), the selected connection geometry and the welding techniques may not support the ability to apply an effective protective coating Gas Technology Institute (GTI) and Edison Welding Institute (EWI) propose to address the interactions between in-field welding and field applied pipe coatings. GTI/EWI will conduct a benchmark study to document the current practices for field welding and coating, including the degree of coordination between these two steps. GTI/EWI will develop field protocols to improve (1) welding and field application practices and (2) coordination between the welders and coaters. This may include changes to current welding and post-welding procedures, coating surface preparation and application procedures, and coating selection. These changes will be verified through laboratory validation testing. Project efforts will involve Pipeline Operators (GTI and EWI contacts) and Coating Appliers and Manufacturers (GTI contacts), including "in kind" funding. A set of clear/concise recommendations will be funneled into appropriate standard development organizations (e.g., NACE/SSPC, AWS, API, AGA, etc.) for incorporation into consensus guides and recommended practices.

Relevant Files & Links