Inspectioneering Journal

Inspect Your Primary Process Small Bore Piping the Right Way, Using Profile Radiography

By Ryan Baggett, General Manager at Pro-Surve Technical Services. This article appears in the May/June 2019 issue of Inspectioneering Journal.


Small Bore Piping (SBP), defined as pipe or piping components that are less than or equal to nominal pipe size (NPS) of 2”, is a major element of every mechanical integrity (MI) program. This category of equipment includes a majority of plant process piping and ancillary systems, including many critical piping systems that are fabricated with SBP, such as, level bridles, flow control loops, pressure and temperature indicating systems, and bypass and pressure relief systems. Despite numerous industry publications, recommended practices, and inspection codes recommending Profile Radiography (PRT) as the preferred method of inspection for pipe diameters of NPS 1” and smaller, equipment owners continue to utilize digital ultrasonic thickness gauging, which is often unreliable.

Digital Ultrasonic Testing (DUT)

Most owner-user facilities utilize embedded DUT technicians to obtain thickness and corrosion data on their equipment and piping systems. In these cases, DUT is often selected because of outdated past practices and as a means to minimize costs. However, when using DUT,  specialized equipment (i.e., special curved or miniature shoes/wedges, as well as diameter specific calibration blocks) is required to accurately assess SBP. Unfortunately, in a career spanning almost three decades, I’ve witnessed that most do not bother obtaining such items prior to inspection. In areas in which you wish to inspect that are insulated, inspection ports are cut in the insulation to facilitate taking DUT readings.

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Comments and Discussion

Posted by Jean-Maurice FOURNIER on July 16, 2019
Thank for sharing Log in or register to read the rest of this comment.

Posted by Eef Coenen on July 16, 2019
We do WTM by DRT also on run pipes up till 3" as... Log in or register to read the rest of this comment.

Posted by mohammed Ashraf on October 19, 2019
How we can inspect to ensure SBP integrity(such... Log in or register to read the rest of this comment.

Posted by Ryan Baggett on October 30, 2019
Depending on the orientation and depth of your... Log in or register to read the rest of this comment.

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