Risk Based Inspection

A: A: FAC needs high velocity and usually shows smooth, orange surfaces, not localized 6 o’clock attack. B: CO2 corrosion doesn’t give you black powder and wouldn’t spike only where liquid sits. C: This one explains the black FeS, the wet sections, and why UT only goes ugly at the bottom. D: Erosion-corrosion leaves directional scars and shows up near fittings, not quietly in dead-flat runs.

A: A: Thermal fatigue needs big ΔT and cycling; that’s not what’s described. B: The 80°C myth trips people up; SCC has shown up well below that with wet chlorides and stress. C: Wet chlorides plus residual stress and stagnation is the classic setup, even at 65°C. D: MIC needs bugs and chemistry evidence; none is called out.

A: A: PSV doesn’t care about wall loss; MAWP drops quietly and RBI owns that risk. B: That’s exactly what the PSV is there for. C: Drain and flare design is a separate safeguard layer, but the PSV still functions. D: That’s a materials and operating envelope issue, not prevented by the valve.

A: A: Assuming as-built without proof is how you miss thin wall. B: Datasheets get revised; they’re not gospel without MOC traceability. C: QA approval doesn’t reconcile engineering intent. D: Conservatism wins until documents line up and RBI isn’t built on hope.