For deadlegs, where should inspector monitor wall thickness?

For deadlegs, where should inspector monitor wall thickness?

• A. Only at a single point
• B. Only at the stagnant end
• C. At both the stagnant end and the active-line connection
• D. Neither

Answer: (C)

In deadlegs, the fluid isn’t moving, so stagnation creates a high risk of corrosion that isn’t uniform along the length. The far or stagnant end tends to collect condensate and deposits, which promotes under-deposit corrosion and localized thinning. At the same time, the point where the deadleg ties into the active line experiences flow disturbances, potential backflow, and changes in velocity or moisture migration, which can drive thinning right at the connection. To reliably detect corrosion, you should measure wall thickness at both the stagnant end and the active-line connection. Relying on a single location can miss thinning that develops in the other area, leaving a defect unchecked.

In deadlegs, the fluid isn’t moving, so stagnation creates a high risk of corrosion that isn’t uniform along the length. The far or stagnant end tends to collect condensate and deposits, which promotes under-deposit corrosion and localized thinning. At the same time, the point where the deadleg ties into the active line experiences flow disturbances, potential backflow, and changes in velocity or moisture migration, which can drive thinning right at the connection. To reliably detect corrosion, you should measure wall thickness at both the stagnant end and the active-line connection. Relying on a single location can miss thinning that develops in the other area, leaving a defect unchecked.