What is the minimum deformation that constitutes a dent?
The repair provisions of the rule establish minimum sizes for dents requiring remediation. These are: Immediate repair conditions include dents of any depth, on the top of the pipeline, that have an indication of metal loss, cracking, or a stress riser. Dents on the top of the pipeline that are greater than 6 percent of pipe diameter in depth are also immediate repair conditions, regardless of other indications. Dents defined as 60-day conditions include dents of any depth, on the bottom of the pipeline, with indication of metal loss, cracking or a stress riser. Topside dents between 3 and 6 percent of pipe diameter in depth are also 60-day conditions. Dents defined as 180-day conditions include those greater than 2 percent of pipe diameter in depth that affect pipe curvature at a girth weld or longitudinal seam, topside dents between 2 and 3 percent of pipe diameter in depth, and bottom-side dents greater than 6 percent of pipe diameter in depth.
