ASME ASME Piping Systems B31 Codes 2 — Questions and Answers
Question 1: Which pressure testing method is preferred by ASME B31.3 for process piping?
- Pneumatic testing
- Hydrostatic testing (Correct answer)
- Radiographic examination only
- Magnetic particle testing
Correct answer: Hydrostatic testing
Hydrostatic testing is the preferred pressure test method in ASME B31.3 because it is safer than pneumatic testing.
Question 2: In ASME piping codes, what does the term 'design pressure' represent?
- The maximum allowable working pressure at ambient temperature
- The most severe coincident pressure and temperature expected during normal operation (Correct answer)
- The hydrostatic test pressure divided by 1.5
- The pressure at which the relief valve is set
Correct answer: The most severe coincident pressure and temperature expected during normal operation
Design pressure is the most severe coincident pressure and temperature condition expected during normal operation, used to determine component thickness.
Question 3: What is the allowable test pressure for a hydrostatic test under ASME B31.3?
- 1.1 times the design pressure
- 1.25 times the design pressure
- 1.5 times the design pressure (Correct answer)
- 2.0 times the design pressure
Correct answer: 1.5 times the design pressure
ASME B31.3 requires hydrostatic test pressure to be at least 1.5 times the design pressure.
Question 4: Under ASME B31.3, a 'normal fluid service' piping system requires what minimum level of radiographic examination for butt welds?
- 100% radiography
- Random (10%) radiography (Correct answer)
- No radiography required unless specified
- Spot radiography on 5% of welds
Correct answer: Random (10%) radiography
Normal fluid service under B31.3 requires random radiographic examination of at least 10% of circumferential butt welds.
Question 5: Which ASME B31 code applies to gas distribution piping within buildings?
- B31.3
- B31.5
- B31.8
- B31.2 (Correct answer)
Correct answer: B31.2
ASME B31.2 covers fuel gas piping systems within buildings and on building exteriors.
Question 6: In ASME piping, what is the purpose of the 'stress intensification factor' (SIF)?
- To reduce allowable stress for high-temperature service
- To account for increased stress at fittings and bends compared to straight pipe (Correct answer)
- To define the safety factor applied to yield strength
- To account for corrosion allowance in wall thickness
Correct answer: To account for increased stress at fittings and bends compared to straight pipe
Stress intensification factors (SIFs) account for the local stress concentration that occurs at elbows, tees, and other fittings relative to girth welds in straight pipe.
ASME ASME Piping Systems B31 Codes 2
Which pressure testing method is preferred by ASME B31.3 for process piping?