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Short note: WI and concrete pipe

Short answer

Wrought iron pipe is lighter, stronger in tension, and can be threaded, but corrodes easily and is costlier. Concrete pipes (plain, RCC, or prestressed) are cheap for large diameters, have long life, and resist corrosion, but are heavy, crack under tension, and are attacked by acids; they are used for gravity mains and sewers.

Write a short note on WI and concrete pipe.

Wrought iron (WI) pipe

Wrought iron pipe is made from rolled and welded wrought iron plate.

  • Merits: lighter than CI, stronger in tension, can be cut and threaded easily, and withstands shocks and vibration.
  • Demerits: costlier than CI; corrodes (rusts) easily unless galvanised or coated, so its life is shorter; it has now been replaced by galvanised steel pipe. It is joined by screwed joints.

Concrete pipe

Concrete pipes are plain (up to 600 mm), reinforced (RCC) or prestressed.

  • Made in a factory by spinning or casting; sizes 150 mm to over 3 m; joints are spigot-and-socket or collar with cement mortar or rubber rings.
  • Merits: cheap for large diameters, long life (75 years), does not corrode, smooth after finishing, and can be made locally.
  • Demerits: heavy and difficult to transport; may crack under tension and leak at joints; attacked by acids, sulphates; cannot withstand high pressure (plain/RCC up to about 30–60 m head; prestressed higher).
  • Used for large gravity mains and sewers.

✓ Answer checked by Claude Opus 5.5 (high effort)

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