Following an initiative that developed from a series of pipeline pigging conferences, the Pigging Products and Services Association (PPSA) was formed in 1990. The Association now has over 95 members, and represents the pigging industry throughout the world.

Providing pigging services

Wholly funded by members through annual subscription fees, the PPSA plays a major role in providing information and sourcing equipment and services for pipeline operators and the industry generally. It has a newly refurbished website where visitors can source the products and services they need, and link to PPSA’s technical information service and other facilities. The Association runs an annual seminar in Aberdeen, occasional training courses on pigging, sponsors lectures and meetings about the subject, and supports relevant conferences.

The PPSA’s annual general meeting is usually held to coincide with the Houston Pipeline Pigging and Integrity Monitoring Conference and Exhibition, in which many PPSA members and their companies are involved. Next year’s will be held on 16 February, at the Marriott Westchase Hotel in Houston.

The Association publishes a regular newsletter Pigging Industry News, which contains news about members’ companies and brief articles of general pigging interest. A number of years ago the PPSA published An Introduction to Pipeline Pigging, a 104 page book which was written to give a comprehensive overview of the most important aspects of pipeline pigging. The book is now in its eighth edition, and continues to be an invaluable source of reference to the wider industry.

The Association also publishes an annual directory, containing contact details of all the members and a brief overview of their capabilities and activities. The directory is free, and currently has a circulated to approximately 5,000 copies around the world.

Why is a pig called a pig?

One of the PPSA's most popular general questions is “How did a pig get its name?”.

There are several possibilities. One story says that two pipeliners were told to clean a pipeline and listen for the pipe cleaner to go by. This pipe cleaner consisted of a steel pipe or mandrel body with flanges welded on both ends. Discs made of leather sheets were stacked together to provide thickness, and attached to the flanges. As the pipe cleaner travelled down the line pushing out debris, it made a squealing, scraping, noise. As the cleaner went by, one pipeliner made a comment to the other about “hearing that pig squeal”.

A similar squealing is attributed to a very early type of pig that was made up from a bale of hay wrapped around by barbed wire, and stuck into the pipeline. A third account claims that an early sphere pig was in fact a pig’s bladder – like a football – that was inflated to the necessary oversize. These stories are generally accepted as possibly being true, although none can be verified.

Pigs through history

For more than half a century pigs consisted of steel bodies and rubber, leather, or urethane cups or discs. The tools were equipped with wire brushes, scrapers, knife blades, and other devices for ploughing. Until 1960, most pipe cleaning was limited to the oil and gas industry. Then the foam bullet-shaped pig was developed – referred to as the ‘polly’ pig because it was made of polyurethane foam.

Although the oil and gas industry remains the largest user of foam pigs, many new industries such as the water and wastewater industry, as well as the chemical processing, petrochemical and mining industries are now using pigs in their pipelines, realising gains such as energy savings, increased flows, decreased pumping pressures, cleaner product, and salvaged product.

The lessons learned from standard pigging operations to clean, dewater, fill, and displace product from pipelines, and the pressures, speeds, and problems incurred, have contributed greatly to the development of instrumented pigs. These were introduced in the late 1960s, and development is continuing to the present day.

There are now literally hundreds of different types of pigs, some with specific or limited use. Apart from the main functions of sweeping, drying, wiping, cleaning, scraping, inspection, and integrity monitoring, ‘semi-intelligent’ pigs now perform additional functions such as alerting and initiating actions involving pumps and valves, making inputs in computerised operations, sometimes through pipe-wall communications, and pipe sealing to allow repairs or tie-ins.