Pipeline Wrinkles

What are pipeline wrinkles?

Pipeline wrinkles are localized deformations of the pipe wall that resemble a waveform and are characterized by alternating inward and outward bulges. These deformations are considered a pipeline defect because they alter the geometry of the pipe and can compromise its structural integrity. Wrinkles are more pronounced than ripples, which are smaller undulations that are often introduced during bending processes.1

Picture collage showing pipeline wrinkles and pipeline ripples in comparison.

  • Ripples: Smaller undulations

  • Wrinkles: Folds or undulations in the pipe wall.

How do wrinkles occur?

Older methods allowed wrinkles to form at the inner bend radius. Even today, inadequate control during bending can create wrinkles or ripples. Excessive bending strain may also result from ground movement, such as landslides or settlement. Ripples are more common in pipelines with a high diameter-to-wall thickness ratio.1

Why are pipeline wrinkles a risk for pipeline safety?

Wrinkles create stress concentrations in the pipe wall that can:

•    Accelerate fatigue and crack initiation.
•    Reduce structural integrity, increasing the risk of leaks or rupture.
•    Cause operational challenges, such as difficulty with pigging during inspections or cleaning.1

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Pipeline Deformation Management

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Source reference

1 The Competence Club, ROSEN, 2025.

Related terms

Image of a pipeline wall showing a crack.

Bending

Pipeline bending is a type of pipeline deformation. It refers to changes in a pipeline’s shape that deviate from its intended alignment. 
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Picture of a dent in a pipeline

Dent

Pipeline dents are deformations in a pipe’s wall caused by an external force. They represent a common defect that occurs when the circular cross-section is permanently altered.
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Illustration of how roof topping on a pipeline can look like.

Roof topping

Roof topping, also referred to as tenting, peaking, or angular misalignment, is a geometric anomaly that occurs at the seam weld of longitudinally welded pipes.
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Picture of a pipeline with an ovality anomaly.

Ovality

Pipeline ovality refers to the out-of-roundness of a pipeline, meaning the pipe’s cross-section deviates from a perfect circle. 
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Pipeline segment with a buckle

Buckles

A buckle is a severe deformation, or partial collapse, of a pipe, caused by lateral instability. This defect occurs when a pipe experiences excessive bending.
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Close up of a dent in the surface of a pipeline.

Geometry defects

Pipeline geometry defects refer to deviations from the ideal circular shape of a pipeline that lead to pipeline deformation.
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Picture of a coating failure on a pipeline.

Mechanical defects

Mechanical damage is caused by external forces acting on a pipeline. This broad term includes defects such as dents, gouges, and coating damage. 
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Picture of a lack of fusion anomaly on a pipeline.

Manufacturing-related defects

Manufacturing-related defects are imperfections in the pipe wall that originate during the production of steel plates or the pipe-forming process. 
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Pipeline running through a landscape affected by ground movements.

Pipeline movement

Pipeline movement refers to the displacement or deformation of a pipeline from its original position, often caused by external forces, such as ground shifts or natural hazards.

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