Q17: How do you choose between a Post-Weld Heat Treatment (PWHT) requirement based on thickness versus process service? PWHT can be triggered by two separate conditions:
API 579 / ASME FFS-1 is the standard for . It provides a multi-level assessment to determine if a piece of static equipment containing a defect (such as localized thinning, pits, cracks, or fire damage) can safely continue operating, requires a de-rating of pressure, or must be repaired/replaced immediately. Technical Scenario-Based Questions
What are the common types of heads used in pressure vessels?The most common are Hemispherical, Ellipsoidal (2:1), Torispherical, and Flat heads. Hemispherical heads are the strongest but most expensive to fabricate. static equipment interview questions updated
What (Junior, Mid, Senior, Lead) is the target role?
Key points: load path verification, weld reinforcement for lifting lugs, API/ASME lifting guidance, and padeye design. Follow-up: How do you find the center of gravity for an assembled exchanger? Q17: How do you choose between a Post-Weld
Key points: thermal expansion, differential expansion, tube-to-tube sheet joint types, tube vibration (fluid/flow-induced), fouling factors in thermal design. Follow-up: Explain how you would handle different thermal expansion rates between shell and tubes.
A: The standard test is NACE TM0284 (now AMPP TM21452). Test specimens are immersed in a sour solution (5% NaCl + 0.5% acetic acid, saturated with H₂S) for 96 hours at 25°C. After exposure, specimens are sectioned and evaluated for Crack Length Ratio (CLR) , Crack Thickness Ratio (CTR) , and Crack Sensitivity Ratio (CSR) . Technical Scenario-Based Questions What are the common types
Q: How do you accommodate thermal expansion in equipment connections? A: Use expansion joints, flexible connectors, sliding supports, expansion loops in piping, and account for differential expansion in nozzle design (slip joints, bellows). Provide proper guides and anchors to control loads.
A leak from the tell-tale hole indicates that the strength weld connecting the nozzle neck to the vessel shell has failed or has a through-thickness defect, allowing the test fluid to pass through.
Which ASME code paragraph is used for calculating the thickness of a pressure vessel shell? ASME Section VIII, Division 1 (or Division 2) governs thickness calculations, employing formulas from UG‑27 for internal pressure and UG‑28 for external pressure. Knowing these references demonstrates your code proficiency.