Pipeline Material and Grade Selection

Posted on February 3, 2013

Material selection

Material selection shall be optimized, considering investment and operational costs, such that Life
Cycle Costs (LCC) are minimized while providing acceptable safety and reliability.
The following key factors apply to materials selection:

• Primary consideration shall be given to materials with good market availability and documented fabrication and service performance.
• The number of different material types shall be minimized considering costs, interchangeability and availability of relevant spare parts.
• Design life.
• Operating conditions.
• Experience with materials and corrosion protection methods from conditions with similar corrosivity.
• System availability requirements.
• Philosophy applied for maintenance and degree of system redundancy.
• Weight reduction.
• Inspection and corrosion monitoring possibilities.
• Effect of external and internal environment, including compatibility of different materials.
• Evaluation of failure probabilities, failure modes, criticalities and consequences. Attention shall be paid to any adverse effects material selection may have on human health,
• Environment, safety and material assets.
• Environmental issues related to corrosion inhibition and other chemical treatments.
• For main systems where materials/fabrication represent significant investments and/or operational costs, an LCC analysis shall be basis for material selection (Ref. Annex A).

Material Grade Selection

In this section selection of material grades for rigid pipelines and risers are discussed.

The following factors are to considered in the selection of material grades:

• cost
• resistance
• weight requirement
• weldability

The higher the grade of steel (up to exotic steels) the more expensive per volume (weight). However, as the cost of producing high grade steels has reduced, the general trend in the industry is use these steel of higher grades.

The choice of material grade used for the pipelines will have cost implications on:

• fabrication of pipeline
• installation
• operation

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