WBPSC AE (PWD) 1998
⭕ A. Above 5 m/sec
⭕ B. Above 18 m/sec
⭕ C. Above 1.8 m/sec
⭕ D. Below 0.5 m/sec
📚 Explanation:
The velocity of water in water mains of 40 cm diameter is usually kept above 1.8 m/sec.
🔹 Maintaining velocity above 1.8 m/sec prevents sedimentation and ensures smooth flow.
🔹 Very high velocities (like above 5 or 18 m/sec) may cause pipe erosion and pressure issues.
The velocity of water in water mains of 40 cm diameter is usually kept above 1.8 m/sec.
🔹 Maintaining velocity above 1.8 m/sec prevents sedimentation and ensures smooth flow.
🔹 Very high velocities (like above 5 or 18 m/sec) may cause pipe erosion and pressure issues.
👉 Therefore, the correct answer is: C. Above 1.8 m/sec
Key Points on Water Velocity in Mains:
- Min velocity ≈ 1.8 m/sec: To avoid sedimentation in 40 cm diameter mains.
- Excessive velocity risk: Velocities above 5 m/sec can erode pipes.
- Design balance: Optimal velocity ensures flow efficiency without pipe damage.
