Work through the three steps: screen the line to set its analysis category, run the approximate sustained + guided-cantilever check, then open the report. Export the PDF from the header once both checks are done.
S_sus = S_p + S_w ≤ S_h
S_exp = i·M/Z ≤ S_a
δ = α·L·ΔT
Engineering tips
- Screening first: any equipment or special trigger forces a Category A line — comprehensive analysis regardless of the approximate result.
- Allowables: S_h and S_a are user-entered placeholders. Use temperature-corrected code values for your material grade before trusting the utilization.
- Guided cantilever: assumes fixed–guided leg ends — best for L/Z shapes with a long main run. A short flexible leg drives the expansion stress up fast.
- Not certified: anchor/guide reactions are screening figures only, never a substitute for nozzle-load qualification.
Recommended values
- Exemption rule: B31.3 §319.4.1 lets you skip formal analysis only if every listed condition is met — check them all.
- Screening index: The Dy/(L−U)² check flags whether the simplified beam rule is valid for your geometry.
- Add flexibility: If borderline, add a loop/offset rather than more anchors to cut the stress range.
- Duplicate systems: The exemption assumes comparison with a proven system of similar size/temperature.
Limitations
- Screening only: Approximate flexibility per §319.4.1 — a fail or borderline result needs formal analysis (e.g. CAESAR II).
- Not included: Support/nozzle loads, SIFs at each fitting, and occasional (wind/seismic) cases are not evaluated.
About the standards
- ASME B31.3: Process Piping.