ASME BPVC Sec VIII Div 1

Key requirements (12)

• Applies to vessels with internal pressure > 15 psig (1.03 barg) up to ~3000 psi (Div 1 sweet spot).
• Joint efficiency E: 1.0 (full radiography), 0.85 (spot RT), 0.70 (no RT) for Type 1 butt joints.
• Shell thickness: t = P·R/(S·E – 0.6·P) for circumferential stress (UG-27).
• Head thickness: t = P·D/(2·S·E – 0.2·P) for 2:1 ellipsoidal heads (UG-32).
• Hydrostatic test pressure: 1.3 × MAWP × (S_test/S_design) — UG-99.
• Pneumatic test (when hydro impractical): 1.1 × MAWP — UG-100.
• Corrosion allowance is added to calculated thickness (not included in S formula).
• MDMT and impact testing per UCS-66 / Figure UCS-66; below the curve, Charpy V-notch impacts are required.
• PWHT thresholds per UCS-56 — generally required above 19 mm thickness for P-No. 1 carbon steels.
• Nozzle reinforcement: area replacement method (UG-37) within reinforcement zone.
• Maximum allowable stress S: from ASME II Part D, Table 1A/1B/3 — temperature dependent.
• Flanges per ASME VIII-1 Appendix 2 (or B16.5 for standard sizes).