Insulation stress is calculated only for straight pipes, bends and tees with polyurethane insulation in buried elements according to EN 13941, EN 253 and GOST 55596 codes.
Strength is assessed based on equivalent and tangent stress acting along and perpendicular to the pipe axis. For more detailed information, see Polyurethane (PUR) Insulation Stress Analysis.
If strength conditions are not met, the corresponding cell in the table will be highlighted in red, and the last column will display the error number, the text of which can be read by hovering over it with the cursor. When printed, the error and warning messages can be found below the table. If strength conditions are met, the "notes" column remains empty.
Property |
Description |
Perpendicular tangent stress |
Circumferential shear stress due to pressure from above-laying backfill soil, τxy see Polyurethane (PUR) Insulation Stress Analysis |
Allowable perpendicular (circumferential) tangent stress |
Allowable perpendicular (circumferential) tangent stress |
Longitudinal tangent stress |
Longitudinal shear stress along the pipe axis due to friction of pipe and soil during longitudinal thermal displacement, τyz see Polyurethane (PUR) Insulation Stress Analysis |
Allowable longitudinal (along pipe axis) tangent stress |
Allowable longitudinal (along pipe axis) tangent stress |
Equivalent stress |
Equivalent stress see Polyurethane (PUR) Insulation Stress Analysis |
Allowable stress |
Allowable stress |
No. |
Note |
Description |
N287 |
Tangent stress exceeds allowable |
Tangent stress in insulation exceeds allowable |
N290 |
Equivalent stress exceeds allowable |
Equivalent stress in insulation exceeds allowable. Laying depth should be reduced |
N289 |
Pipeline loads from soil pressure must be removed |
Error occurs when pipe wall stability is lost under surrounding soil pressure, for example, in vacuum elements. In this cases, wall thickness should be increased, laying depth should be decreased, or soil weight should be decreased |
After analysis: Output > Insulation Stress