Issuing body
ASME
Latest edition
2022 Edition
Region
USA, Global
Equipment items
0
Scope
Practices for assembling bolted flange joints; bolt-tightening sequences and torque calculations.
Key requirements (7)
- Bolted flange joint assembly guidelines (post-construction).
- Pre-tension target: typically 50–60% of bolt yield (varies with gasket type).
- Bolt-up sequence: cross-pattern in 4–5 passes (25%, 50%, 100% of target torque, then circular passes).
- Lubrication critical: K-factor of nut factor varies 5–10× with lube quality.
- Joint qualification: training + practical testing per Appendix A.
- Re-torque after 24 hours due to gasket creep / relaxation.
- Hydraulic tensioning preferred for studs > 1" (more even loading).