Piping Material Engineering_September 2024 Batch

A: A: The arithmetic is fine, but piping specs rarely carry fractional CA; this misses the standard practice embedded in most B31.3 specs. B: Two-sided loss is a pressure design concept, not how corrosion rate is reported by inspection. C: This matches how CA is actually frozen in specs — calculated, then rounded up to a standard value that survives fabrication tolerances. D: There's no basis for doubling CA unless the corrosion rate itself is uncertain or episodic, which isn't stated.

A: A: Procurement logic, not contract logic; this shifts risk without authority. B: This is how contracts are enforced when edition dates aren't updated — ugly, but defensible. C: Jurisdictional adoption affects code compliance, not material procurement acceptance. D: Mill flexibility doesn't override a binding project spec, even if everyone wishes it did.

A: A: CA was invented for this exact slow, predictable loss mode. B: Pitting eats through wall locally; average allowance doesn't buy time where the pit forms. C: Erosion is still thickness loss over time, even if accelerated. D: Oxygen corrosion is ugly but still broadly uniform if exposure is global.

A: A: Coatings help general corrosion but don't stop sulfide stress risk if conditions drift. B: 304L is weak against chlorides; pitting risk shows up early. C: 316L buys some margin, but chloride plus H2S at temperature pushes it. D: Duplex handles chlorides and sulfide environments with far better resistance when properly heat treated.