SPED Pressure Testing & Commissioning 3 — Questions and Answers
Question 1: What ASME B31.3 hydrostatic test pressure multiplier is applied to the design pressure for normal fluid service?
- 1.1×
- 1.25×
- 1.5× (Correct answer)
- 2.0×
Correct answer: 1.5×
ASME B31.3 requires a hydrostatic test pressure of at least 1.5 times the design pressure for normal fluid service piping.
Question 2: During commissioning of a utility water system, a valve is found to pass slightly when in the closed position. This deficiency is classified as which punch list category?
- Category A (blocks mechanical completion) (Correct answer)
- Category B (can be addressed after startup)
- Category C (cosmetic, no action needed)
- Category D (requires design change)
Correct answer: Category A (blocks mechanical completion)
Valve passing in the closed position is a Category A punch item because it can affect safe operation and must be resolved before mechanical completion sign-off.
Question 3: Which test method uses acoustic emission sensors placed on the pipe exterior to detect leak location during pressurization?
- Hydrostatic test
- Pneumatic soap-bubble test
- Acoustic emission testing (AET) (Correct answer)
- Radiographic testing
Correct answer: Acoustic emission testing (AET)
Acoustic emission testing detects and locates leaks by analyzing high-frequency stress waves emitted from crack growth or fluid escaping through defects.
Question 4: When pressure testing a piping system with multiple pressure ratings, the test pressure is governed by which component?
- The highest-rated component in the system
- The lowest-rated component in the system (Correct answer)
- The average of all component ratings
- The pipeline designer's recommendation
Correct answer: The lowest-rated component in the system
The test pressure must not exceed the capability of the weakest (lowest-rated) component in the system to prevent damage during testing.
Question 5: Which commissioning activity verifies that instrument transmitters are reading correctly at known process conditions before startup?
- Loop checking (Correct answer)
- Hydrostatic testing
- HAZOP review
- Functional safety assessment
Correct answer: Loop checking
Loop checking involves applying a known signal or process condition and verifying the entire measurement loop reads correctly at the control system.
Question 6: A piping system is returned to service after a repair weld without re-testing. Under ASME B31.3, what minimum post-weld examination is required?
- Visual examination only
- 100% radiographic examination
- Pressure test at original test pressure
- Examination per the original construction code and Owner approval (Correct answer)
Correct answer: Examination per the original construction code and Owner approval
ASME B31.3 requires repairs to be examined and tested in accordance with the original construction requirements, subject to Owner-authorized alternatives.
Question 7: What is the purpose of a 'golden weld' or 'tie-in weld' lock-out procedure during pressure testing?
- To identify welds exempt from PWHT
- To prevent test pressure from entering sections not yet ready for testing (Correct answer)
- To mark welds requiring radiographic examination
- To denote welds made by certified welders
Correct answer: To prevent test pressure from entering sections not yet ready for testing
Tie-in weld isolation procedures ensure that pressurized test sections are physically separated from adjacent piping not yet constructed or cleared for testing.
SPED Pressure Testing & Commissioning 3
What ASME B31.3 hydrostatic test pressure multiplier is applied to the design pressure for normal fluid service?