API 570 Question Bank (API 570 QB001)

25) Soil-to-air (S/A) interfaces for buried piping are a location where localised corrosion may take place. If the buried part is excavated for inspection, how deep should the excavation be to determine if there is hidden damage?

a) 12 to 18 inches

b) 6 to 12 nches

c) 12 to 24 inches

d) 6 to 18 inches

26) At concrete-to-air and asphalt-to-air interfaces of buried piping without cathodic protection, the inspector look for evidence that the caulking or seal at the interface has deteriorated and allowed moisture ingress. If such a condition exists on piping systems over __________ years old, it may be necessary to inspect for corrosion beneath the surface before resealing the joint.

a) 8

b) 5

c) 15

d) 10

27) An example of service-specific and localised corrosion is:-

a) Corrosion under insulation in areas exposed to steam vents

b) Unanticipated acid or caustic carryover from processes into non-alloyed piping

c) Corrosion in deadlegs

d) Corrosion of underground piping at soil-to-air interface where it ingresses or egresses.

28) Erosion can be defined as:

a) Galvanic corrosion of a material where uniform losses occur

b) Removal of surface material by action of numerous impacts of solid or liquid particles

c) Gradual loss of material by a corrosive medium acting uniformly on the material surface

d) Pitting on the surface of a material to the extent that a rough uniform loss occurs

29) A combination of corrosion and erosion results in significantly greater metal loss that can be expected from corrosion or erosion alone. This type of loss occurs at:

a) High-velocity and high-turbulence areas

b) Areas where condensation or exposure to wet hydrogen sulphide or carbonates occur

c) Surface-to-air interfaces f buried piping

d) Areas where gradual loss of material occurs because of a corrosive medium

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