Piping flexibility: how is thermal expansion in pipelines typically accommodated in industrial layouts?

Introduction / Context:
Thermal expansion can produce significant axial growth in pipelines, leading to stress, nozzle loads, and potential failure if not managed. Flexibility analysis (per recognized codes) ensures thermal strains are absorbed safely. This question asks which methods are used to accommodate expansion.

Given Data / Assumptions:

• Pipelines transporting hot or cold fluids with temperature cycles.
• Standard supports, guides, and anchors exist per design practice.
• Objective is to limit stresses and loads within allowable values.

Concept / Approach:
There are multiple proven strategies. Metallic expansion joints (bellows) provide axial flexibility over a short length but require careful control of pressure thrust and guide spacing. Directional changes (e.g., U-loops, offsets, dog-legs) distribute thermal movement over longer runs, often preferred for reliability. Shaping the routing to create flexible legs (long legs, elbows) increases system compliance without special devices.

Step-by-Step Solution:
Option (a): Expansion joints — valid when engineered and protected against squirm and overextension.Option (b): Directional changes/loops — common, robust solution.Option (c): Shaping the line (e.g., offset legs) — equivalent to (b) in effect, increases flexibility.Thus, all three approaches are valid; select (d).

Verification / Alternative check:
Piping codes and flexibility analysis tools (e.g., Caesar II) evaluate thermal case stresses; solutions often combine anchors, guides, and expansion features to meet allowable limits.

Why Other Options Are Wrong:
Each of (a)–(c) is individually valid; choosing only one ignores common industry practice.

Common Pitfalls:
Installing bellows without guides/anchors; ignoring pressure thrust; underestimating nozzle loads on equipment.

Final Answer:
All (a), (b) and (c)