Wall Thickness Calculation of Offshore Pipelines

Wall Thickness Calculation of Offshore Pipelines (General) Wall thickness of offshore pipelines is determined mainly based on internal design pressure or hydrostatic external pressure.  After selecting selecting appropriate appropriate wall wall thickness, axial axial and combined combined stresses stresses shall shall be checked checked to be within acceptable limits. The following procedure is recommended for designing pipeline wall thickness: Step 1: Define safety class, location class, and contained material class (based on design basis of the pipeline and selected design code) Step 2: Calculate nominal (or minimum based on selected design code) wall thickness of the pipeline Step 3: Calculate nominal (or minimum based on selected design code) wall thickness to withstand external pressure Step 4: Add wall thickness allowance for corrosion (and fabrication tolerances) to maximum calculated thickness from Step 2 and Step 3 Step 5: Select next higher available thickness from standards such as API-5L. Step 6: Check selected wall thickness for hydrostatic test condition Step 7: Check wall thickness and D/t for handling and fabrication difficulties These steps will be discussed in future posts in detail.