The weight of the pipe, valves, insulation, and the fluid inside.
| Term | Meaning | |------|---------| | | Constant forces – pipe weight, fluid weight, insulation, fittings. | | Thermal expansion | Dimensional change due to temperature difference (ΔT). | | Secondary stress | Self-limiting (e.g., thermal bending). No failure if yield occurs once. | | Primary stress | Non-self-limiting (e.g., pressure, weight). Can cause catastrophic failure. | | Allowable stress range | Per ASME B31.3, based on material properties and cycles. | | Anchor point | Fixed restraint – zero movement in all directions. | | Cold spring | Intentionally pre-stressing pipe during installation to reduce thermal loads. | The weight of the pipe, valves, insulation, and
When a straight pipe runs between two anchors, thermal expansion has nowhere to go. The pipe buckles or breaks the anchor. Solution: introduce , changes in direction , or bellows . | | Secondary stress | Self-limiting (e
: Includes specific technical data for determining anchor locations and minimum loop sizes to accommodate thermal expansion. Self-Directed Structure Can cause catastrophic failure