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CWB LEVEL 2 EXAM 2025 BRAND NEW
ACTUAL EXAM WITH ANSWERS.
What are some critical factors for Corrosion Under Insulation? -
correct answer -It affects externally insulated piping and
equipment and those that are in intermittent service or operate
between:
10F(-12C) and 350F(175C) for carbon and low alloy
140F(60C) and 400F(205C) for austenitic stainless steels and
duplex stainless steels.
Corrosion rates will increase with increasing metal temperature up
to the point where the water evaporates quickly (ex. Corrosion
becomes more severe at metal temperatures between boiling
point 212F(100C) and 350F(121C), where water is less likely to
vaporize and insulation stays wet longer.
Insulating material that hold moisture (wick) is a problem
Equipment that operates below water dew point creates condense
water on metal surfaces
Cyclic thermal operation or intermittent service can increase
corrosion
, Page | 2
Plants located in areas with high rain fall
Environments that provide airborne containments such as
chlorides, stack emissions (SO2), cooling tower drift
What kind of equipment is affected by corrosion under insulation?
- correct answer -All equipment is susceptible to CUI
What are some examples where corrosion under insulation can
occur? - correct answer -Can be found on equipment with
damaged insulation, vapor barriers, weatherproofing or mastic, or
protrusions through the insulation or at insulation termination
points such as flanges.
Piping or equipment with damaged/leaking steam tracing.
Localized damage to coating or paint systems
Where water/moisture will naturally collect.
Deadlegs (vents, drains, and other similar items)
Pipehangers
CWB LEVEL 2 EXAM 2025 BRAND NEW
ACTUAL EXAM WITH ANSWERS.
What are some critical factors for Corrosion Under Insulation? -
correct answer -It affects externally insulated piping and
equipment and those that are in intermittent service or operate
between:
10F(-12C) and 350F(175C) for carbon and low alloy
140F(60C) and 400F(205C) for austenitic stainless steels and
duplex stainless steels.
Corrosion rates will increase with increasing metal temperature up
to the point where the water evaporates quickly (ex. Corrosion
becomes more severe at metal temperatures between boiling
point 212F(100C) and 350F(121C), where water is less likely to
vaporize and insulation stays wet longer.
Insulating material that hold moisture (wick) is a problem
Equipment that operates below water dew point creates condense
water on metal surfaces
Cyclic thermal operation or intermittent service can increase
corrosion
, Page | 2
Plants located in areas with high rain fall
Environments that provide airborne containments such as
chlorides, stack emissions (SO2), cooling tower drift
What kind of equipment is affected by corrosion under insulation?
- correct answer -All equipment is susceptible to CUI
What are some examples where corrosion under insulation can
occur? - correct answer -Can be found on equipment with
damaged insulation, vapor barriers, weatherproofing or mastic, or
protrusions through the insulation or at insulation termination
points such as flanges.
Piping or equipment with damaged/leaking steam tracing.
Localized damage to coating or paint systems
Where water/moisture will naturally collect.
Deadlegs (vents, drains, and other similar items)
Pipehangers
