4 Most Common Issues That Lead To Unpiggable Pipelines

4 Most Common Issues That Lead To Unpiggable Pipelines

Regular upkeep is vital to a pipeline system’s optimal function, which can be achieved through checks in the form of integrity testing and good old-fashioned maintenance. These processes are indispensable because pipelines are still prone to wear and tear despite their robust construction and, at some point, will experience reduced flow or get blocked completely. To prevent these issues from affecting business productivity, operators must deploy pipeline pigging solutions periodically to clear out the debris that might have accumulated. That said, clearing out pipelines will not always be a seamless process, and there are different scenarios wherein it seems like your pipes have become unpiggable. Read on as we outline what these common scenarios are and tips to address them.


How do pipelines become unpiggable?

Pipes can become unpiggable if there is excessive tuberculation or a complete blockage in the line. While most line problems can be pigged, certain steps must be taken first to make a pigging solution feasible, such as hydrojetting. The jetting process involves using high-pressure water jets to eliminate debris, clogs, and other buildup in preparing for the actual pigging. With that said, the following are the key factors that can render your pipelines to become completely unpiggable.


1. Tuberculation

Tuberculation occurs when mounds of rust build up on the interior of metal pipes and resist the smooth flow of the liquid or product. If left unchecked, these blockages can grow larger and harden enough to fully obstruct movement in the pipes. There are many ways to remove tuberculation, with one of the most popular being the Picote process.

This cleaning procedure uses a camera to inspect the length of the pipeline and check if it is ready for a cleanout. Once the extent of the debris is determined, a section of the pipeline is removed, creating an opening that the Picote machine can attach to and begin the cleaning process.

However, it is important to note that not all tuberculated pipes can be cleaned and pigged in this way; those created in the 1970s or earlier will have to be replaced entirely. Minor tuberculation can still be resolved via pipe descaling, but if this problem takes place in pipes that are well past their service life, it is more practical to declare the system unpiggable.


2. Total blockage

A pipeline that becomes 100% blocked will be unpiggable in most cases since there should be at least 30% of the flow to facilitate the movement of any cleaning solution through the line. In the case of total blockage, the next best alternative to pigging would be removing the section where the debris has grown too large and either clearing it externally or outright replacing the entire area.


3. Short-diameter pipes

Pigging is almost always an impractical cleaning solution for short and small pipes that measure 10 inches or less. To ensure effective pigging, one must find a suitable launch and retrieval location, which is just not possible with short-diameter pipes. Despite being unpiggable, there are other ways to clean out these pipeline systems, such as the Picote process.


4. Unconventional valve structures

Apart from the diameter, the structure of the valves themselves could make a pipeline unpiggable. For instance, butterfly valves and plug valves with unique designs may prevent foam pigs and other pigging equipment from passing through. Cleaning out piping systems with such valves often requires pigging between the valves or replacing them with full port units to ensure that the pigs can pass through.



Thanks to the many technological advancements in pipeline pigging and maintenance, the term ‘unpiggable’ is becoming less and less common, and experts now even deem that there is no longer such a thing as an unpiggable pipeline, only challenging ones that require more sophisticated cleaning interventions.

Pharmchem Engineering is the brand you can trust for a wide range of quality industrial engineering supplies, including pipe pigging equipment, anti-vibration mounts, industrial hoses, dry disconnect couplings, and more. With our decade of experience in the industry and commitment to excellence, you can rest assured that all our products, whether off-the-shelf or custom-made to your needs, are fully tested to specified conditions before leaving the factory.

Don’t hesitate to contact us at any time for more information regarding our industrial equipment supply.