When Are Pipelines Unpiggable? Possible Solutions

Pipeline maintenance and integrity testing are checks that should be performed regularly to ensure the optimal functioning of your pipeline system. Although pipelines are made of heavy-duty metal or plastic materials, they are still prone to wear and tear from years of use. At some point in your pipeline's operation, when it experiences low flow or stops functioning completely, you will have to apply various pigging solutions to clear out debris that might have accumulated.

However, simply cleaning out your pipelines doesn't always work out seamlessly. When a pipeline becomes ridden with tuberculation or the blockage is too huge, it becomes unpiggable, requiring more complex solutions.

In this article, we discuss the different scenarios that make a pipeline unpiggable and how they can be addressed.

When Are Pipelines Unpiggable?

If there is too much tuberculation or a total blockage in the line, it can become unpiggable. Most line issues can be pigged, but sometimes, steps need to be taken first to make pigging feasible. One such approach is jetting the pipeline first, which involves using high-pressure water jets to remove clogs, buildup, and debris. Hydro jetting is an eco-friendly way of clearing your pipes or preparing them prior to pigging.

If it has been a while since your pipeline was last maintenanced, total blockage and tuberculation can be expected. In this instance, your pipeline could be rendered unpiggable, even with pre-jetting. Below are some scenarios when pigging might not be possible.

Tuberculation in the Pipeline

Tuberculation happens when mounds of rust accumulate on the inside of your metal pipe, thus making it resistant to the flow of water. It is caused by the combination of bacteria and oxygen and can become so large and hardened that it obstructs water movement, rendering your pipeline eventually useless.

There are many ways to address tuberculation, but one of the most effective is the Picote cleaning process. In this procedure, a camera is used to inspect the pipeline and determine its readiness for a cleanout. When the extent of the debris is identified, a section of the pipeline is removed, usually along the 90-degree bend, and the Picote machine is attached to begin the process.

However, not all tuberculated pipelines are piggable; those built in the 70s, and earlier, usually need to be replaced completely. Minor tuberculation issues can still be addressed through pipe descaling, but when the problem has become so large on a pipe that's well past its lifespan, it's more practical to declare it unpiggable.

Pig is Blocked From Passing Through the Pipeline

If a pipeline is completely blocked, it becomes unpiggable. In order to travel through a line, the flow should be present by at least 30% to facilitate movement. In this scenario, the best alternative to pigging pipelines would be to remove the section that contains the blockage and clear it externally or replace the entire area.

Unconventional Valve Structures

Another reason why a pipeline could become unpiggable is the structure of the valves themselves. Eccentric plug valves and butterfly valves are uniquely designed that pigging equipment isn’t able to pass through. To clean this area, specialists would have to pig between the valves or take them out and replace them with full port units to allow for pig passage; however, Ice Pigging™ (another APS service offering) is another viable alternative to this specific problem.

Short Diameter Pipes

When your pipes are small and short, measuring 10 inches or less, pigging might not be a practical cleanout option. To pig effectively, you need a good launch location and a retrieval location, which isn't possible with a short pipe. Although unpiggable, the site can still be cleaned out using the Picote process.

Next Steps for Unpiggable Pipelines

With the advancements in pipeline cleaning and maintenance technology, the term "unpiggable" has started to lose its finality. Pipeline experts argue that there's no such thing as unpiggable pipelines, only those that are tricky to manage and will require unique interventions.

APS provides pigging solutions for pipelines of any size, structure, and issue. We have several options based on the problem and why the pipe needs to be pigged (or cleaned out using alternative techniques). Using our smart solutions, let us help you track the problem at the source and find the most efficient and safe cleanout strategies that will keep your pipelines in top condition for many years to come.

Contact American Pipeline Solutions and learn more about our unique pipeline pigging and cleanout solutions.