API 510 Pressure Testing 3 — Questions and Answers
Question 1: What type of fluid is preferred for hydrostatic pressure testing per ASME and API 510?
- Hydraulic oil
- Water (Correct answer)
- Nitrogen
- Air
Correct answer: Water
Water is the preferred hydrostatic test medium because it is essentially incompressible and minimizes stored energy in the event of a failure.
Question 2: When is a pneumatic test permitted instead of a hydrostatic test per API 510?
- When water is unavailable and the engineer approves (Correct answer)
- When the owner prefers it for convenience
- When the vessel design pressure is below 100 psi
- When the vessel is made of stainless steel
Correct answer: When water is unavailable and the engineer approves
A pneumatic test may be substituted when the vessel cannot be safely filled with water or when design considerations prevent hydrostatic testing, with proper engineering approval.
Question 3: Per API 510, what is the maximum temperature of the test water during a hydrostatic pressure test to minimize brittle fracture risk?
- 32°F (0°C)
- At least 60°F (16°C) (Correct answer)
- 120°F (49°C)
- No temperature requirement exists
Correct answer: At least 60°F (16°C)
The test water temperature should be at least 60°F (16°C) to reduce the risk of brittle fracture during pressure testing.
Question 4: After completing a successful hydrostatic test, what must be done before the vessel is returned to service?
- Coat the interior with rust inhibitor
- Drain and dry the vessel if required by service (Correct answer)
- Perform a pneumatic leak test to verify tightness
- Reapply insulation immediately
Correct answer: Drain and dry the vessel if required by service
The vessel must be drained and dried as needed before returning to service, particularly if the process fluid is incompatible with water.
Question 5: Who is responsible for witnessing or reviewing the pressure test documentation for a vessel repair under API 510?
- The plant manager
- The repair contractor's QC manager only
- The authorized pressure vessel inspector (API 510) (Correct answer)
- The insurance underwriter
Correct answer: The authorized pressure vessel inspector (API 510)
The authorized pressure vessel inspector (API 510 certified) is responsible for witnessing or reviewing pressure test documentation for repairs.
Question 6: A vessel repaired by welding is to be pressure tested. Which document must be completed before the test?
- Repair organization's invoice
- Manufacturer's data report
- Repair/Alteration Form (API Form) (Correct answer)
- ASME U-1 form
Correct answer: Repair/Alteration Form (API Form)
A Repair/Alteration Form must be completed and accepted by the authorized inspector before a pressure test following repair or alteration.
Question 7: When pressure testing a vessel with multiple chambers, which approach is typically taken?
- Test all chambers simultaneously at the highest required pressure
- Test each chamber independently at its respective test pressure (Correct answer)
- Only test the highest-pressure chamber
- Average the test pressures of all chambers
Correct answer: Test each chamber independently at its respective test pressure
Each chamber must be tested independently at its own required test pressure to ensure each compartment meets its design requirements.
API 510 Pressure Testing 3
What type of fluid is preferred for hydrostatic pressure testing per ASME and API 510?