Friday, November 4, 2016

Plastic Liners for Steel Pipelines Prevent Corrosion, but Pipelines Still Require Inspection Post Lining

Corrosion is the number one enemy of pipeline integrity. A lot of minds have been put to work to try and solve this problem, and engineering technologies have been developed to protect metal pipelines from deterioration: external urethane coatings, epoxy coatings and cathodic protection are just a few tools in the arsenal of the pipeline industry to preserve their assets. Many pipeline owners have also turned to internal pipe liners, such as those developed by United Pipeline Systems. Let's do an assessment of the benefits and risks of using them:

Benefits of Plastic Pipe Liners:

  • Protects against internal corrosion
  • Protects against internal erosion
  • Protects against chemical attack
  • Works at high and low temperatures in many different fluids and gases
  • Effective in pipelines transporting CO2, sour gas, salt water, 3-Phase oil/gas and tailings materials
  • Extends the life of a pipeline

What Can Go Wrong With Lined Pipes?

Now that you've learned that plastic liners have so many benefits, you also must be aware that they need to be regularly inspected and monitored. Pipeliners have a risk of collapse. Failure of the liner can be caused by an excess of gas pressure that occurs between the liner and the wall of the pipeline, causing the liner to dent inwards. This can happen if the anulus is not vented properly. Also, if the pipeline encounters a vacuum condition while in-service or during maintenance, the liner can collapse. Liners do not prevent external corrosion or third party excavation damage. If the pipeline is thinned due to external corrosion, the liner may not be able to take the internal pressure, and the line may fail and leak.

Pipeline liners are not a foolproof solution. They can be extremely effective, but ensure that you're diligent about monitoring and inspecting your pipelines for best results. Make your operators aware of the problems that liners can encounter and train new hires to bring them up to speed quickly. To detect external corrosion through liners up to 1" thick, contact Russell NDE at 1 (800) 661-0127, or by e-mail to schedule an inspection today.