570 Study Guide - Section 9 - Buried Piping Inspection Flashcards
Inspection of buried process piping is different from other process piping inspection, because of:
A. Significant internal corrosion that cannot be monitored
B. Significant external corrosion due to corrosive soils
C. Potential overhead traffic that increases stress on pipe
D. Excessive water content in soils
B. Significant external corrosion due to corrosive soils
Which of the following methods is effective in finding active corrosion on an unearthed underground pipe?
A. Wenner four-pin
B. Holiday tester
C. Close-interval potential survey
D. Acoustic emission testing
C. Close-interval potential survey
The corrosiveness of the soil for buried piping systems can be determined by measuring the soil resistivity, As soil resistivity. As soil resistance increases, the soil:
A. Become non-corrosive
B. Become less corrosive
C. Become more corrosive
D. Clay content increases
B. Become less corrosive
Lower levels or soil resistivity are:
A. Non-corrosive
B. Less corrosive
C. More corrosive
D. Less conductive of CP protective currents
C. More corrosive
Measurements of soil resistivity should be performed using:
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:
A. API 561
B. API 2201
C. ASTM A307
D. ASTM G57
A. API 561
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
Which of the following is an acceptable way to determine the wall thickness of buried piping?
A. Close interval potential survey
B. Video Cameras
C. Holiday testing
D. Excavating
D. Excavating
Which of the following is NOT a limitation on using an intelligent pig?
A. Might get stuck if line size reduces
B. Need special connections to launch and retrieve the pig
C. Thickness readings are inaccurate
D. Difficult to go around typical elbows
C. Thickness readings are inaccurate
When excavating pipe for insepction, the:
A. Inspector must monitor the excavation
B. Last few inches should be dug up by hand
C. Minimum length to excavate is 25 feet
D. Best area to dig is the area where the highest soil resistivity
B. Last few inches should be dug up by hand
Guided wave UT may be used to inspect buried piping. One installation (equipment setup) may be able to screen:
A. 15 feet
B. 25 feet
C. 50 feet
D. 100 feet
A. 15 feet
What is the suggested interval for above grade visual surveillance on buried piping systems?
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 piping inspector
B. Piping engineer
C. Owner/user
D. Tank farm operation 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 year
B. 5 years
C. 10 years
D. 15 years
B. 5 years
For buried piping systems in lengths greater than 100’ and NOT cathodically protected, evaluation of soil corrosivity should be performed every:
A. 1 year
B. 5 years
C. 10 years
D. 15 years
B. 5 years
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 years at the plant is quite low
C. Cover it up and report to the engineer. That way if it fails we’ll both go to jail. Be sure to pick an engineer you like!
D. Dig further. Obviously you’re a boring inspector who doesn’t like to take chances
D. Dig further. Obviously you’re a boring inspector who doesn’t like to 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 extent beyond the ground line
B. The casing ends are properly sealed
C. The pressure carrying pipe is properly coated and wrapped
D. The casing pipe is made of material that does not cause galvanic corrosion
D. The casing pipe is made of material that does not cause galvanic corrosion
A buried pipe in the tank farm area does NOT have any cathodic protection. The soil resistivity is 1000 ohms-cms. What is the recommended interval for excavating or pigging this pipe?
A. 2.5 years B. 5 years C. 10 years D. 15 years E. Whenever the authorized inspector believes it is necessary
B. 5 years
A buried pipe does NOT have effective cathodic protection. The soil resistivity is about 8000 ohms-cms. What is the recommended interval for excavating or pigging this pipe?
A. 5 years B. 7.5 years C. 10 years D. 15 years E. Whenever the authorized inspector believes it is necessary
C. 10 years
A buried pipe does NOT have effective cathodic protection. The soil resistivity is about 12,000 ohms-cms. What is the recommended interval for excavating or pigging this pipe?
A. 5 years B. 7.5 years C. 10 years D. 15 years E. Whenever the authorized inspector believes it is necessary F. Inspection is not needed
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 going to be leak tested in lieu of excavation. The maximum operation pressure is 70 psig. The pipe has a design pressure of 180 psig. What is the recommended test pressure?
A. 70 psig B. 77 psig C. 105 psig D. 180 pgig E. 208 psig F. 270 psig
B. 77 psig
An underground pipe is going to be leak tested in lieu of excavation. The 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 re-pressurized 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 test 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 nay cathodic protection. The soil resistivity is 1000 ohms-cms. What is the recommended interval for leak testing this pipe?
A. 2.5 years B. 5 years C. 10 years D. 15 years E. Whenever the authorized inceptor believe it is necessary
A. 2.5 years
A buried pipe does NOT have effective cathodic protection. The soil resistivity is about 12,000 ohms-cms. What is the recommended interval for leak testing this pipe?
A. 5 years B. 7.5 years C. 10 years D. 15 years E. Whenever the authorized inspector believes it is necessary
B. 7.5 years
A buried pipe has effective cathodic protection. The soil resistivity is about 8000 ohms-cms. What is the recommended interval for leak testing this pipe?
A. 5 years
B. 7.5 years
C. 10 years
D. 15 years
C. 10 years
An underground pipe is going to be 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?
A. 162 psig B. 170 psig C. 171 psig D. 175 psig E. 180 psig
C. 171 psig
An underground pipe is going to be 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?
A. 140.0 psig
B. 142.5 psig
C. 145.0 psig
D. 150.0 psig
B. 142.5 psig
Which of the following is an alternative to leak testing an underground pipe?
A. Holiday survery
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 this makes finding leaks enumerable experine!)
A. Helium or sulfur hexafluoride
What is a recommended way to inspect repairs on coatings that have been peformed on buried piping?
A. A low-voltage holiday detecor
B. A high-voltage holiday dector
C. A low-voltage Wenner Four Pin
D. A high-voltage Wenner Four Pin
B. A high-voltage holiday dector
A leak is discovered on a buried pipe in the tank farm. The pipe is excavated and clamped. It is recommeded that the location of the clamp shall be:
A. Covered and forgotten
B. Surface marked in the field
C. Recorded in the inspection records and may be surface marked in the field.
D. Recorded in the inspection records and shall be surface marked in the field.
C. Recorded in the inspection records and may be surface marked in the field.
A leak is discovered on a buried pipe in the tank farm. The pipe is excavated and is reparied with a non-welded clamp. This clamp:
A. Must removed and the pipe repaired at the first opportunity
B. Can be considered repair if approved by an engineer
C. Can be considered repair if approved by an engineer or inspector
D. Can be considered repair if approved by the jurisdiction
A. Must removed and the pipe repaired at the first opportunity
