Small Bore Piping (SBP)

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In the refining and chemical processing industries, Small Bore Piping (SBP) is generally process piping that is two inches or less in diameter. Small bore piping typically branches off of the main process piping and is often used as relief lines and drain piping.

The refining industry has had a history of failures occurring in small bore threaded pipe connections. These connections are subject to several different types of damage, including but not limited to: fatigue cracking, stress corrosion cracking (SCC), corrosion under insulation (CUI), and accelerated erosion/corrosion of the pipe wall. This is due to a combination of internal and external corrosion forces acting on small diameter, thin walled pipe connections, as well as fluid turbulence and crevice corrosion acting on threaded connections.

Although SBP failures are not as likely to lead to major process safety incidents as the failure of larger primary piping, numerous instances have been reported where the failure of SBP led to reliability impacts (process unit shutdown) or large fires, when secondary effects of the ensuing fire caused the failure of other larger pipe and vessels.

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Articles about Small Bore Piping (SBP)
July/August 2021 Inspectioneering Journal

This article illustrates the value of digital radiography as an efficient tool to visualize corrosion and other small bore piping anomalies without disturbing insulation, as well as using PRT in conjunction with UTT to survey small diameter lines.

May/June 2019 Inspectioneering Journal

While planning methods for thickness data acquisition in any Inspection Data Management Program, PRT should be considered as a cost-efficient, effective way to increase the value of your program for small bore piping or any other suitable situation.

Authors: Ryan Baggett
Online Article

Updated editions of both API 570 and API RP 580 were recently released by the American Petroleum Institute.

Authors: John Reynolds
November/December 2013 Inspectioneering Journal

Small bore piping is present in many variations throughout numerous industries. This article will address an incident involving a small bore piping failure that occurred on a 140,000 BPD crude distillation unit in the refining industry.

September/October 2000 Inspectioneering Journal

This article continues to outline the 101 essential elements that need to be in place, and functioning well, to effectively and efficiently, preserve and protect the reliability and integrity of pressure equipment (vessels, exchangers, furnaces,...

Authors: John Reynolds
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