API 510 Pressure Testing 5 — Questions and Answers
Question 1: Per API 510, when can a pressure test be omitted following an alteration?
- When the alteration is minor and the owner decides it is unnecessary
- When the authorized inspector agrees and a thorough NDE examination is performed as an alternative (Correct answer)
- When the vessel is not in a regulated jurisdiction
- When the vessel is less than 5 years old
Correct answer: When the authorized inspector agrees and a thorough NDE examination is performed as an alternative
The authorized inspector may waive pressure testing after an alteration if thorough NDE is performed and the inspector is satisfied with the results.
Question 2: What is the purpose of slowly increasing pressure in stages during a pneumatic test?
- To allow the test medium to reach temperature equilibrium
- To allow for leak detection at lower pressures before reaching full test pressure (Correct answer)
- To reduce pump wear
- To satisfy code documentation requirements
Correct answer: To allow for leak detection at lower pressures before reaching full test pressure
Staged pressure increases allow inspectors to detect and address leaks at lower, safer pressures before applying full test pressure.
Question 3: Which type of NDE method is most commonly substituted as an alternative to a pressure test in API 510?
- Visual examination only
- Radiographic testing (RT) or ultrasonic testing (UT) of completed welds (Correct answer)
- Hardness testing
- Positive material identification (PMI)
Correct answer: Radiographic testing (RT) or ultrasonic testing (UT) of completed welds
Radiographic or ultrasonic testing of completed weld joints is the most common alternative NDE method accepted in lieu of pressure testing.
Question 4: A vessel is being repressurized after repair. If the MAWP has been reduced as a result of the repair, the pressure test should be based on:
- The original MAWP before the repair
- The new reduced MAWP (Correct answer)
- The original design pressure from the nameplate
- 50% of the original MAWP
Correct answer: The new reduced MAWP
The pressure test must be based on the new, reduced MAWP to reflect the actual current capability of the repaired vessel.
Question 5: Which personnel safety precaution is critical during the pressurization phase of a pneumatic test?
- All personnel must wear full SCBA
- Personnel should be cleared from the area or behind barriers during pressurization to full test pressure (Correct answer)
- Only the inspector may be within 50 feet of the vessel
- No special precautions are required below 100 psi
Correct answer: Personnel should be cleared from the area or behind barriers during pressurization to full test pressure
Personnel should be evacuated or positioned behind barriers during pneumatic pressurization due to the explosive energy released if the vessel fails.
Question 6: When a pressure vessel is hydrostatically tested after installation in a tower or column, what factor affects the required test pump capacity?
- Ambient temperature
- The volume of the vessel and the rate at which it must be pressurized (Correct answer)
- The type of process fluid to be used in service
- The elevation of the test site above sea level
Correct answer: The volume of the vessel and the rate at which it must be pressurized
Pump capacity must be sufficient to fill the vessel volume and pressurize it to test pressure within an acceptable time frame.
Question 7: After a successful pressure test, where should the test results be recorded per API 510 requirements?
- Only in the contractor's records
- In the vessel's inspection and maintenance history records (Correct answer)
- On the vessel nameplate only
- Verbally communicated to plant management is sufficient
Correct answer: In the vessel's inspection and maintenance history records
Test results must be documented in the vessel's official inspection and maintenance history file as part of the permanent vessel records.
API 510 Pressure Testing 5
Per API 510, when can a pressure test be omitted following an alteration?