🔍 Key Concepts

• waterside vs. fireside boiler tube problems • How suspended solids or particles in water move at high velocity inside tubes • Difference between corrosion (chemical attack) and physical wear (erosion/abrasion)

💭 Think About

• Which choice involves solid or hard particles physically rubbing or impacting the metal surface inside the tube? • Which options describe mainly chemical attack (corrosion) rather than mechanical scraping or scouring? • Think about what happens at high water velocity in bends and narrow spots: what could "sandblast" the metal surface from the water side?

✅ Before You Answer

• Identify which answer clearly involves solid particles moving with the water that can cause erosive wear. • Eliminate options that mainly describe chemical corrosion processes instead of mechanical abrasion. • Ask: would this condition still wear the tubes if the problem chemical were neutralized, or does it require physical particles in motion?