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 The most suitable pipe material for sewers will be vitrified clay or Stoneware (SW )pipes, due to their corrosion resistance characteristics, advantages and superiority over other types of pipes when used in moderate loading and careful handling conditions. The SW pipes are being manufactured in sizes from 100 mm to 375 mm as per IS: 651 -1971.

Advantages of SW pipes

  1. They have better resistance to corrosion from most acids,
  2. They have good abrasion resistant to erosion due to grit and high velocity. Because SW pipes are rigid and not totally depend on pipe bedding materials for structural support, they may be used where future excavation for other services is anticipated which may cause lesser disturbance.
  3. The SW pipes manufactured with push-fit flexible spigot and socket joint with elastomeric 0-ring, are more advantages in installing under water condition and for speedy execution.

Disadvantages of SW pipes

  1. Only few of the many types of clay which occur naturally are suitable for the manufacture of the pipes. Hence SW pipe factories are located only at sites where favourable clay is available.
  2. The pipes are manufactured in length of 60 cm (some factories in our country are manufacturing in 90 cm length with great difficulties in handling the fresh molded pipes prior to firing) only resulting in more number of joints requiring considerable time for installation.
  3. The SW pipes are brittle and so are susceptible to impact damage. If dropped, pipes may crack or break.
  4. The SW pipes often necessitate special bedding or concrete cradling to improve field supporting strength.