Natural gas pipelines are affected by thermal expansion, vibrations, and small equipment movements. Flexible connections and appropriate expansion devices can reduce mechanical stress, but they must be used only where specified.
Thermal expansion
Temperature changes cause changes in pipeline length. In long straight runs, the forces that develop can be significant.
Vibrations
Burners, fans, compressors, or other machinery can transfer vibrations to the line. Proper support and controlled use of flexible elements reduce the problem.
When to use a flexible connection
It should not be used as a solution for misalignment or faulty construction. It must be suitable for the gas, pressure, temperature, and expected mechanical movement.
Supports and anchors
Flexible connections function properly only when the rest of the system has correct support and anchor points. Otherwise, they may be subjected to loads for which they were not designed.
Inspection
They are checked for cracks, deformations, corrosion, leakage, and abnormal stress. If there is noticeable movement or deformation, the cause must be investigated rather than simply replacing the element.
