In a hot tapping system, the high point area may corrode. Why is that?

In a hot tapping system, the high point area may corrode. Why is that?

• A. Convective currents set up in deadlegs
• B. High pressure
• C. Low temperature
• D. Salt deposition

Answer: (A)

In hot tapping systems, the high point tends to form a dead leg where flow is restricted and liquid can become stagnant. This creates a confined pocket where condensate and dissolved gases accumulate. Small convection currents, driven by temperature and pressure differences, circulate within that pocket and continually bring oxidizers and moisture to the metal surface. That ongoing contact supports electrochemical corrosion cells, making the high point area more susceptible to corrosion. The other factors listed don’t explain this localized, stagnant-zone corrosion as directly as the presence of a dead leg with circulating currents does.

In hot tapping systems, the high point tends to form a dead leg where flow is restricted and liquid can become stagnant. This creates a confined pocket where condensate and dissolved gases accumulate. Small convection currents, driven by temperature and pressure differences, circulate within that pocket and continually bring oxidizers and moisture to the metal surface. That ongoing contact supports electrochemical corrosion cells, making the high point area more susceptible to corrosion. The other factors listed don’t explain this localized, stagnant-zone corrosion as directly as the presence of a dead leg with circulating currents does.