Design of Pressure Vessel using COMPRESS – Different Load Cases

A: Ignoring this pushes you toward brittle cracking in service and a shutdown you can't explain after the fact. Intermittent H2S at low temperature points to sulfide stress cracking as the controlling mechanism, and COMPRESS inputs must reflect NACE material limits so allowable stresses and thickness aren't overstated.

A: Combining them blindly risks missing an elastic buckling failure that shows up without warning during startup or draining. ASME treats external pressure as a separate instability problem, and COMPRESS follows that logic so collapse resistance isn't diluted by unrelated load combinations.

A: If you wave this off, the vessel fails test and the turnaround slips days. Hydrotest often governs due to higher liquid head and test pressure, and COMPRESS correctly flags it. Adjusting thickness or test pressure is the legitimate way to bring stresses back under code limits.

A: Missing this leads to cracked nozzles after restart, even though the shell looks fine on paper. COMPRESS handles global pressure load cases well, but it doesn't capture local thermal expansion loads at blocked outlets, which need separate assessment or piping flexibility review.

A: Letting this slide sets you up for a failed independent check or late MOC. Rising utilization points to creeping scope or data drift, and revalidating weights and seismic inputs early avoids a redesign when the margin finally disappears.

A: Crediting wasted metal leads to nonconservative stress results and surprise failures late in life. ASME logic strips corrosion allowance from strength while keeping its mass, and COMPRESS mirrors that so bending and support reactions aren't understated.

A: Choosing the wrong tweak leaves bending unchanged and forces a thicker shell. Bending stress is geometry-driven, and saddle spacing directly controls it, making it the effective lever when wind plus deadweight governs.

A: Assuming system-level safety from a shell-only pass leads to brittle failures at attachments during a fire. COMPRESS evaluates shell stress under reduced allowable, but local components and supports still need separate fire and thermal checks.

A: Forcing a redesign now stalls the turnaround with little safety gain. ASME intent treats hydrotest as a controlled condition where seismic coincidence isn't required, and documenting that boundary keeps the design compliant without unnecessary changes.