Pipeline Pigging: How It Works, Types, And Applications

Pipeline Pigging: How It Works, Types, And Applications

Organisations that use any sort of pipeline will need or already use pipeline pigs, specialised tools used for unclogging, cleaning, and improving pipeline performance. Pigging is a process that uses projectile tools called Pipeline Integrity Gauges (or PIG for short) to move out every last drop of liquid inside a pipeline system, which means removing 99% of the product leftover in the pipes. It is typically performed when there is a change of liquids, the pipes are due for a cleaning, or the processing is complete.

Many industries and organisational processes rely on pigging recovery systems to ensure that as much processed liquid is recovered instead of disposed of or flushed away, which leads to waste. These diverse industries include food and drink, oils, household goods, paints, solvent production, and many more.


Why and when is pigging used?

As mentioned, pipeline pigging is a process that sends tools called pigs into pipelines to remove any remaining liquids, scrub and clean the pipe walls, and flush out debris and blockages along the way. Pipeline pigs scrape the insides of piping systems with brushes and are specifically designed for various pipe standards to ensure they have the perfect measurements and perform well without causing damage or getting stuck.

Apart from removing liquids and cleaning, pipeline pigs are also used for detecting potential damages inside pipelines that cannot be detected in any other way. These damages can range from the early onset of cracks and leaks to corrosion and other serious damages. Identifying these issues is critical to enable timely resolution before they become severe problems.

Pipeline pigging is done throughout a pipeline’s lifecycle, from pre-commissioning to decommissioning. Apart from the pigs themselves, other pigging equipment is needed for the process, such as launchers and receivers, which are installed at both ends of the pipe to insert and remove the pig.


Pipeline pigging applications

The following is a summary of the common uses of pipeline pigging;

1. Pipeline cleaning

Buildups and deposits inside pipe systems are removed via mechanical and chemical pigging processes. Cleaning activities include:

  • Pre-commission cleaning
  • Debris removal following construction
  • Before in-line inspection for accurate data
  • Before and after hydrostatic testing
  • Decoking

2. Gauging

This process determines internal bore restrictions by using specialised pigs outfitted with soft metal disks that bend when coming into contact with obstructions.

  • Drying
  • Maintenance and repair
  • Dewatering
  • Pipeline inspections and integrity management


Types of utility pigs

  • Metal or mandrel pigs

Mandrel pigs have a metal body design that is customisable with interchangeable components. This feature, allowing for multiple attachments, makes the tool highly versatile and extends its longevity.

  • Foam pigs

Foam pigs come in various densities of polyurethane foam which ranges from low, medium, and high. Low-density foam pigs are suited for dewatering due to their high absorption. In contrast, medium and high-density foam pigs excel at moving greater volumes of liquid and debris than low-density foam pigs.

  • Spherical pigs

Spherical pigs are available in the same material type and formats as foam pigs and are mainly used for piping systems with tight bends.

  • Solid cast pigs

Solid cast pigs are constructed out of moulded polyurethane. As it is moulded into a single piece, solid cast pigs can be made with more seals, which is helpful in cases like batching.



Efficiency is critical for any kind of pipeline. Pipe pigging helps ensure this efficiency by removing every last drop of liquid in the system, clearing blockages and buildup, and keeping the inner pipe walls hygienic. Moreover, the process helps detect potential damages along the system to avoid severe pipeline damages that can harm employees and the environment.

If you need high-quality pipe pigging equipment custom-built to accommodate your piping system, we have you covered. At Pharmchem Engineering, our sophisticated pipe pigging equipment is a proven solution that has helped many companies improve their pipe maintenance operations over the decades since our inception. Apart from pipe pigging equipment, we also offer other high-quality industrial products such as anti-vibration mounts, expansion joints, dry disconnect couplings, and a wide range of hoses that include rubber hoses, stainless steel hoses, and Teflon hoses. For more details about our products, don’t hesitate to reach out to us today.