Section 9: Inspection of Buried Piping (API 570 pg 70-75) Flashcards
- Inspection of buried process piping is different from other process piping, because of:
A. The potential for significant internal corrosion that cannot be monitored
B. The potential for significant external corrosion due to corrosive soils
C. Potential overhead traffic that increases stress on pipe
D. Excess water content in soils
B. The potential for significant external corrosion due to corrosive soils
- Which of the following methods is effective in finding active external corrosion on a buried underground pipe?
A. Wenner Four-Pin
B. Cathodic protection
C. Closed-interval potential survey
D. Acoustic emission testing
C. Closed-interval potential survey
- A coated buried pipe has been in service for a number of years. What method can be used to evaluate the effectiveness of the coating?
A. ACVG
B. DCVG
C. ACPR
D. DCPR
B. DCVG
- The corrosiveness of the soil for buried piping can be determined by measuring the soil resistivity. As soil resistance increases, the soil:
A. becomes-non corrosive
B. becomes less corrosive
C. becomes more corrosive
D. clay content increases
B. becomes less corrosive
Lower levels of soil resistivity are:
A. Non-corrosive
B. Less corrosive
C. More corrosive
D. Less conductive of CP protective currents
C. More corrosive
- When measuring soil resistivity, the recommended tool to use is
A. The Wenner Four-Pin Method
B. A holiday tester
C. A close-interval potential survey
D. a CP potential survey
A. The Wenner Four-Pin Method
- When The Wenner Four-Pin Method is used to measure soil resistance, it should be done in accordance with
A. API 651
B. API 2201
C. ASTM A307
D. ASTM G57
D. ASTM G57
- When monitoring cathodic protection, refer to the requirements in:
A. API 651
B. API 2201
C. ASTM A307
D. ASTM G57
A. API 651
- Which of the following should be checked when evaluating a CP system?
A. Pipe resistance
B. Pipe-to-soil potential
C. Soil inductance
D. Soil-to-pipe current
B. Pipe-to-soil potential
- Which of the following is an acceptable way to determine the wall thickness of buried piping?
A. Intelligent pigging
B. Video cameras
C. Holiday testing
D. Close interval potential survey
A. Intelligent pigging
- Guided wave examination may be used to inspect buried piping. One installation (equipment setup) may be able to screen:
A. 15 feet or longer
B. 25 feet or longer
C. 50 feet or longer
D. 100 feet or longer
A. 15 feet or longer
- During a guided wave examination, the distance the wave travels and the accuracy of the measurements is based on several factors. Which of the following is NOT a factor?
A. Degree of corrosion
B. External coatings
C. Grade of carbon steel
D. Soil conditions
C. Grade of carbon steel
- What is the suggested interval for the above-grade visual surveillance on a buried pipe? (Open Book)
A. 6 months
B. 1 year
C. 5 years
D. 10 years
A. 6 months
- Who is responsible to ensure that the above grade visual surveillance is performed at the required intervals
A. Authorized inspector
B. Piping engineer
C. Owner / User
D. Tank farm operations supervisor
C. Owner / User
- For poorly coated buried piping systems where cathodic protecting potential are inconsistent, the pipe-to-soil potential survey may be performed every:
A. 1-2 years
B. 3-5 years
C. 5-10 years
D. 10-15 years
B. 3-5 years
- For buried piping systems in lengths greater than 100 feet and not cathodically protected, evaluations of soil resistivity should be performed at what interval?
A. Every 1 year
B. Every 5 years
C. Every 10 years
D. Based on likelihood resistivity has changed
D. Based on likelihood resistivity has changed
- When buried piping is inspected by excavating, what is the minimum length to excavate?
A. 2 to 4 feet
B. 4 to 6 feet
C. 6 to 8 feet
D. 8 to 10 feet
C. 6 to 8 feet
- Significant external damage to the coating is discovered on an excavated pipe. The damage extends into the wall of soil. What should be done?
A. Cover it up. Out of sight out of mind!
B. Cover it up. The likelihood of a failure during my remaining plant years is quite low.
C. Cover it up and report it to the engineer. That way if it fails, you’ll both go to jail. Be sure to pick an engineer that you like!
D. Dig further. Obviously, you’re a boring inspector who doesn’t like take chances
D. Dig further. Obviously, you’re a boring inspector who doesn’t like take chances
- If a buried piping system is contained inside a casing pipe, which of the following is NOT something the inspector should verify?
A. Both ends of the casing extend beyond the ground line
B. The casing ends are properly sealed
C. The pressure carrying pipe is properly coated and wrapped
D. The minimum distance between the casing pipe and the process pipe is 6”
D. The minimum distance between the casing pipe and the process pipe is 6”
- A buried pipe in the tank farm area does not have any cathodic protection. The soil resistivity is 1000 ohm-cms. What is the recommended interval for excavating or pigging this pipe? (Open Book)
A. 2.5 years
B. 5 years
C. 10 years
D. 15 years
E. Whenever the AI believes it is necessary
B. 5 years
- A buried pipe does NOT have effective cathodic protection. The soil resistivity is about 8000 ohm-cms. What is the recommended interval for excavating or pigging this pipe? (Open Book)
A. 5 years
B. 7.5 years
C. 10 years
D. 15 years
E. Whenever the AI believes it is necessary
C. 10 years
- A buried pipe does NOT have effective cathodic protection. The soil resistivity is about 12,000 ohm-cms. What is the recommended interval for excavating or pigging this pipe? (Open Book)
A. 5 years
B. 7.5 years
C. 10 years
D. 15 years
E. Whenever the AI believes it is necessary
D. 15 years
- Which of the following is an alternative to inspecting buried piping by excavation?
A. Leak test at a pressure 10% greater than maximum operating pressure
B. Leak test at a pressure 10% greater than design pressure
C. Holiday testing
D. Close interval potential survey
A. Leak test at a pressure 10% greater than maximum operating pressure
- An underground pipe is leak tested in lieu of excavation. The maximum operation pressure is 70 psig. The pipe design pressure is 180 psig. What is the recommended test pressure?
A. 70 psig
B. 77 psig
C. 105 psig
D. 180 psig
E. 198 psig
F. 270 psig
B. 77 psig
- An underground pipe is going to be leak tested in lieu of excavation. This leak test should be maintained for a total of:
A. 2 hours
B. 4 hours
C. 6 hours
D. 8 hours
D. 8 hours
- An underground pipe is going to be leak tested in lieu of excavation. The pressure should be checked and the line repressurized after:
A. 2 hours
B. 4 hours
C. 6 hours
D. 8 hours
B. 4 hours
- An underground pipe is going to be leak tested in lieu of excavation. The piping should be excavated and inspected when the pressure at the end of the test decreases by more than:
A. 1%
B. 3%
C. 5%
D. 10%
C. 5%
- A buried pipe in the tank farm area does not have any cathodic protection. The soil resistivity is 1000 ohm-cms. What is the recommended interval for leak testing this pipe? (Open Book)
A. 2.5 years
B. 5 years
C. 10 years
D. 15 years
E. Whenever the AI believes it is necessary
A. 2.5 years
- A buried pipe does NOT have effective cathodic protection. The soil resistivity is about 12,000 ohm-cms. What is the recommended interval for leak testing this pipe? (Open Book)
A. 5 years
B. 7.5 years
C. 10 years
D. 15 years
B. 7.5 years
- A buried pipe has effective cathodic protection. The soil resistivity is about 8,000 ohm-cms. What is the recommended interval for leak testing this pipe? (Open Book)
A. 5 years
B. 7.5 years
C. 10 years
D. 15 years
C. 10 years
- An underground pipe is leak tested in lieu of excavation. The maximum test pressure is 180 psig. What is the minimum acceptable pressure allowed at the end of this test? (Open Book)
A. 162 psig
B. 170 psig
C. 171 psig
D. 175 psig
E. 180 psig
C. 171 psig
- An underground pipe is leak tested in lieu of excavation. The maximum test pressure is 150 psig. What is the minimum acceptable pressure allowed at the end of this test? (Open Book)
A. 140 psig
B. 142.5 psig
C. 145 psig
D. 150 psig
B. 142.5 psig
- Which of the following is an alternative to leak testing an underground pipe?
A. Holiday survey
B. Potential survey
C. Tracer gas test
D. Wenner evaluation
C. Tracer gas test
- Which of the following gases are typically used in a tracer gas test?
A. Helium or sulfur hexafluoride
B. Chlorine or fluoride
C. Hydrohexadramine or freon
D. Hydrogen or propane (for smokers - makes finding leaks a memorable experience!)
A. Helium or sulfur hexafluoride
- What is a recommended way to inspect repairs on coatings that have been performed on buried piping?
A. A low-voltage holiday detector
B. A high-voltage holiday detector
C. Low-voltage Wenner Four Pin
D. High-voltage Wenner Four Pin
B. A high-voltage holiday detector
- A leak is discovered on a buried pipe in the tank farm. The pipe is excavated and clamped. The clamp location shall be:
A. Covered and forgotten
B. Surface marked in the field
C. Recorded in the inspection records and may be surface marked in field
D. Recorded in the inspection records and shall be surface marked in field
C. Recorded in the inspection records and may be surface marked in field
- A leak is discovered on a buried pipe in the tank farm. The pipe is excavated and is repaired with a non-welded clamp. This clamp:
A. Must be removed and the pipe repaired at the first opportunity unless a piping engineer approves an extension
B. Can we considered a permanent repair if approved by an engineer
C. Can can be considered a permanent repair if approved by an engineer and inspector
D. Can be considered a permanent repair if approved by the jurisdiction
A. Must be removed and the pipe repaired at the first opportunity unless a piping engineer approves an extension
