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Pigging

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Pigging is an in-line inspection (ILI) technique in which devices referred to “pigs” are inserted into pipelines to perform cleaning and inspection activities. Pigging can be conducted on a variety of pipelines sizes without having to stop the flow of material through the line.

A pig is placed into the pipeline at a valve or pump station that has a special configuration of valves and pipes where the tool can be loaded into a receiver. Once the receiver is closed and sealed, the pig is then driven down the line, either being pulled through by a cable or being pushed through by the flow of product.

Traditionally, pigging was used purely as a way to clean pipelines. The pig was simply placed in one end of a pipeline and pushed through the line by the product flow. It scrapes the sides of the pipe as it travels, removing dirt and debris as it goes.

For inspection, pigs can be fitted with various nondestructive examination technologies that can scan the pipe through which it travels. These are often referred to as "smart pigs." There are several different types of smart pigs utilized in ILI activities, each with its own set of advantages and disadvantages. Some are more effective at detecting certain types of corrosion or damage in different types of pipes, depending on their NDE capabilities. More recently though, some manufacturers are combining the various functions of these separate tools into one. This way a single tool can now be used to detect several different types of damage, making it more efficient and effective.

Intelligent ("Smart") Pigging

Intelligent Pigging is an inspection technique whereby an inspection probe, often referred to as a "smart" pig, is propelled through a pipeline while gathering important data, such as the presence and location of corrosion or other irregularities on the inner walls of the pipe.

What makes intelligent pigging different is that smart pigs are capable of performing advanced inspection activities as they travel along the pipe, in addition to just cleaning it. Smart pigs use nondestructive examination techniques such as ultrasonic testing and magnetic flux leakage testing to inspect for erosion corrosion, metal loss, pitting, weld anomalies, and hydrogen induced cracking, among others. They are also able to gather data on the pipeline's diameter, curvature, bends, and temperature.

Smart pigging provides a number of advantages over traditional forms of pipeline inspection. It allows pipelines to be cleaned and inspected without having to stop the flow of product. It also allows the a pipeline to be completely inspected without having to send inspectors down its entire length. Finally, it provides cleaning and inspection services at the same time, saving companies both time and money.

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Articles about Pigging
March/April 2020 Inspectioneering Journal

Universally, smart or intelligent pigging is now a standard practice for the inspection of fired heater and serpentine boiler coils. Understanding this technology can greatly assist with maintenance planning and the prevention of unexpected failures.

Authors: Tim Haugen
September/October 2019 Inspectioneering Journal

This article presents two cases studies demonstrating how properly conducting baseline fired heater tube inspection aids in early discovery and correction of defects, avoiding unexpected in-service failures, and more.

Authors: Tim Haugen
March/April 2017 Inspectioneering Journal

The purpose of this article is to describe the various in-line inspection (ILI) technologies that are currently available to the market. The pros, cons, and applicability of each type of tool will be discussed in greater detail.

Authors: Matt Ellinger
September/October 2016 Inspectioneering Journal

Although all ultrasonic smart pigging providers claim the ability to detect wall thinning and tube deformations to some degree, the inspection surface coverage, resolution, minimum wall thickness detection and reporting capabilities may vary...

Authors: Tim Haugen
May/June 2015 Inspectioneering Journal

For traditional in-line inspection (ILI) vendors, considering 21.4 miles of a piggable 4” diesel pipeline is typically not a big deal. However, significant threats like 3rd party damage and external corrosion seem to come with the territory in...

Partner Content

What do you need: CONSULTING - Subject matter experts, consultants, or team of highly skilled engineers to help solve my problem. SOFTWARE - My team requires software, products, or resources that will solve the problem. TRAINING - I require...

Online Article

Jim Svetgoff, Corrosion Advisor at Devon Energy recently interviewed with American Business Conferences for the Crude Pipeline Asset Integrity Congress 2014.

September/October 2014 Inspectioneering Journal

The pigging industry has developed a tremendous range of techniques and technologies, and it is probably fair to say that there are few pipelines in the world that cannot be cleaned and inspected, although the success of such operations will often...

Authors: John Tiratsoo
November/December 2013 Inspectioneering Journal

Inspectioneering recently had the privilege of speaking with Tom Wanzeck, Vice President of Integrity Services with Willbros Group, Inc. Tom spent more than 20 years managing assets on the owner-operator side before making the leap to the service...

Authors: Tyler Alvarado
July/August 2013 Inspectioneering Journal

Inspection and fitness-for-service assessments of critical in-plant piping systems are a concern for the chemical industry. This presents a potentially insurmountable task and discovery of a number of areas where the condition is at risk.

Authors: James R. Widrig
Partner Content

TEAM believes that quality inspections are the key to reliability. Our inspection crews are made up of specialty trained, experienced technicians who adhere to the highest quality standards. Our API 653 inspectors deliver thorough, reliable...

May/June 2013 Inspectioneering Journal

Refineries and chemical plants own and operate numerous process heaters (e.g. gas reformers, CCRs, etc.) as part of the standard assets throughout the facilities. Many heater coil configuration designs are flanged at both ends; however, there are...

November/December 2012 Inspectioneering Journal

Various fired heater designs in refineries and chemical plants contain common headers (e.g. Arbor coil configurations, CCRs, etc.) as part of their overall serpentine coil design. Accessing the interior of individual coils through the common header...

September/October 2012 Inspectioneering Journal

The refining industry has applied ultrasonic-based intelligent pigging to inspect serpentine coils in fired heaters since the 1990s. Today, thousands of serpentine coils in fired heaters are inspected annually at process facilities around the globe.

May/June 2012 Inspectioneering Journal

A self-propelled in-line inspection tool tested at Electric Power Research Institute and utilized in Europe can traverse a complex piping configuration and discriminate areas of metal loss. This tool is becoming available to inspect traditionally...

Authors: Clay Goudy
January/February 2010 Inspectioneering Journal

For years refinery and chemical plant operators have utilized ultrasonic-based intelligent pig technology to inspect coils in convection and radiant sections of fired heaters. This proven technology provides accurate inspection data which allows...

Partner Content

Pro-Surve recently invested in the latest portable Higher Order Modes Clusters (HOMC) Guided Wave Testing tool, a new concept for the inspection of inaccessible regions using short-range guided waves. Inspection is carried out from the accessible...

November/December 2009 Inspectioneering Journal

Pipeline integrity management programs are largely driven by regulatory compliance and are typically budgeted years in advance. Operators of all sizes are looking for ways to reduce expenditures related to operational efficiency and safety in order...

Authors: Stefan Papenfuss
July/August 2007 Inspectioneering Journal

The integrity of pipelines is a natural concern for pipeline operators, and so the ability to detect corrosion, erosion and mechanical damage in pipes is therefore of significant interest. Traditional methods of detection, such as pigging and...

September/October 2006 Inspectioneering Journal

Active corrosion in onshore and offshore pipelines is an increasing problem. Consequently, pipeline operators regularly use intelligent inspection pigs to detect and size corrosion. Inspection data can be combined with probability based...

Authors: F Egan, D G Jones, J Healy
November/December 2004 Inspectioneering Journal

Reliable "intelligent pig technology" is now readily available to the refining industry which can provide quick / comprehensive inspection to both "convection" and "radiant" sections in process furnace piping coils. Both tabular data formats along...

May/June 1998 Inspectioneering Journal

Part 1 included a review of current tube inspection practices in convection and radiant sections of heaters/furnaces in the refining and chemical industries. The authors also presented a new inspection device combining laser image mapping of the...

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