In a deterioration scenario where both corrosion and erosion are present, which three areas should be inspected to detect the combined damage?

In a deterioration scenario where both corrosion and erosion are present, which three areas should be inspected to detect the combined damage?

• A. Upstream of control valves, upstream of pump discharges, and upstream of orifices.
• B. Downstream of control valves, downstream of pump discharges, and downstream of orifices.
• C. Downstream of pressure relief devices, downstream of pumps, and inside valve bodies.
• D. Around flanges, around elbows, and at weld seams.

Answer: (B)

Deterioration from both corrosion and erosion tends to occur where flow energy is released downstream of devices that create a pressure drop or flow disturbance. After a control valve, the flow is throttled and becomes high-velocity and turbulent, which impinges on the downstream surfaces and combines with chemical attack to wear away material. The same logic applies downstream of pump discharges, where the jet of fluid at high velocity and possible cavitation or turbulence accelerates wear on the piping interior. Downstream of orifices, the constricted flow accelerates and then reattaches, producing a focused jet and turbulence that drive both erosion and corrosion. So, the best areas to inspect for this combined damage are the sections immediately downstream of the control valve, downstream of the pump discharge, and downstream of orifices. These locations concentrate the energy of the fluid and are where erosion-enhanced corrosion is most likely to manifest. Upstream regions and areas like flanges, elbows, or weld seams can show corrosion for other reasons, but they’re not as indicative of erosion-corrosion caused by downstream flow disturbances.

Deterioration from both corrosion and erosion tends to occur where flow energy is released downstream of devices that create a pressure drop or flow disturbance. After a control valve, the flow is throttled and becomes high-velocity and turbulent, which impinges on the downstream surfaces and combines with chemical attack to wear away material. The same logic applies downstream of pump discharges, where the jet of fluid at high velocity and possible cavitation or turbulence accelerates wear on the piping interior. Downstream of orifices, the constricted flow accelerates and then reattaches, producing a focused jet and turbulence that drive both erosion and corrosion.

So, the best areas to inspect for this combined damage are the sections immediately downstream of the control valve, downstream of the pump discharge, and downstream of orifices. These locations concentrate the energy of the fluid and are where erosion-enhanced corrosion is most likely to manifest. Upstream regions and areas like flanges, elbows, or weld seams can show corrosion for other reasons, but they’re not as indicative of erosion-corrosion caused by downstream flow disturbances.