Pipe Thermal Growth Calculator (in / 100 ft)
Reports free thermal growth between anchors in inches and in/ft from the tabulated in/100 ft coefficient, Δ = coeff × L/100. Coefficients in ASME B31.1 Appendix B and B31.3 Appendix C are already referenced to 70 °F, so do not multiply by ΔT again.
The field engineer's expansion calculation: code appendices tabulate total thermal expansion as inches per 100 ft from 70 °F to the operating temperature, so growth between anchors is one multiplication. This card does it with clean unit handling and feeds the expansion-loop and spring-travel calculations.
Method
Δ = (coefficient in/100ft) × L(ft) / 100
The coefficient is the tabulated total expansion for your material between installation and operating temperature (e.g. B31.1 Appendix B / B31.3 Appendix C tables — user-supplied). For coefficients per unit temperature, use the expansion-loop card's α·ΔT·L form instead.
| Inputs | ||
|---|---|---|
| coeff | Tabulated expansion (user-supplied) | in/100 ft |
| L | Anchor-to-anchor length | ft |
| Outputs | ||
| growth | Free thermal growth | in |
| per foot | Unit growth | in/ft |
Limitations — what this calculator is not
- Free (unrestrained) growth — actual displacement at any point depends on anchor and guide layout; use it as the input to loop sizing and spring-hanger travel, not as a predicted movement at a specific support.
- The tabulated coefficient already spans a temperature range from its reference (usually 70 °F) — don't multiply by ΔT again.
Worked example — fixture-verified
Steam line with tabulated expansion 2.6 in/100 ft at operating temperature, 120 ft between anchors — the PVP Suite selftest case.
| Given | ||
|---|---|---|
| Coefficient | 2.6 | in/100 ft |
| Length | 120 | ft |
Step by step
- Growth: 2.6 · 120/100 = 3.12 in (0.026 in/ft).
| Result COMPUTED | ||
|---|---|---|
| Free growth | 3.12 | in |
| Per foot | 0.026 | in/ft |
Locked to the PVP validation value within 1×10⁻⁶.
thermal-growth.json — case “PVP: 2.6 in/100ft over 120 ft” (tolerance 0.000001) — in the
calc-core release gate. It re-runs on every commit; a red fixture blocks deployment.
See the validation methodology.Sources & citations
- ASME B31.1 Appendix B / B31.3 Appendix C — thermal expansion data (user-supplied; tables not embedded).
Per the source & citation policy, allowable-stress and factor table values are user-supplied — this page and the app cite paragraph numbers and never reproduce ASME table data.
FAQ
Where do I find the in/100 ft coefficient?
The thermal-expansion appendices of the governing code (B31.1 App. B, B31.3 App. C) tabulate it by material group and temperature, referenced to 70 °F. Manufacturer data serves for plastics. Enter the value for your operating temperature directly.
Related calculators
- Expansion Loop / Leg Sizing Calculator (Guided Cantilever) — Growth feeds directly into leg and loop sizing
- Displacement Stress Range Check (ASME B31.3 ¶319.4.4) — Restrained growth becomes the moment ranges checked there
- Stress Intensification & Flexibility Factor Calculator (B31.3 Appendix D) — SIFs intensify the stresses this growth produces