Pipeline Ovality

What is pipeline ovality?

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

How does ovality in pipelines occur?

Ovality typically develops due to the following:

  • Local concentrated loads: External forces acting on the pipe during installation or operation.
  • Pipeline bends: Curvature introduced during construction or alignment can distort the pipe’s shape.

These factors can cause the pipe to become slightly flattened or elongated, resulting in an oval, rather than a circular, profile. 

Picture of a pipeline with an ovality anomaly.

  • Here you can see an example of pipeline ovality, also known as out-of-roundness. The pipeline is strongly deformed and no longer forms a perfect circle.

Why is pipeline ovality a risk for pipeline safety?

Ovality can compromise pipeline safety by creating uneven stress distribution, increasing the risk of fatigue and deformation under pressure, and making the pipeline more vulnerable to other defects, such as cracks.

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Pipeline Deformation Management

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Source reference

1 The Competence Club, ROSEN, 2025.

Related terms

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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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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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Pipeline wrinkles are localized deformations of the pipe wall that resemble a waveform and are characterized by alternating inward and outward bulges. 
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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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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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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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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 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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