--- title: "Requirements of a good pipe material" subject: "Water Supply Engineering" chapter: 8 key: "semester_5/water_supply_engineering:requirements-good-pipe-material" source: https://www.bctengineer.com/q/semester_5/water_supply_engineering/requirements-good-pipe-material site: BCT Engineering --- # Requirements of a good pipe material Water Supply Engineering · Chapter 8: Conveyance of Water - Asked in: 2072 Kartik, 4 marks; 2075 Asoj, 2 marks (asked 2 times) - Video: [Water Distribution | Pipe material](https://www.youtube.com/watch?v=m46pglO46aY) — American Water College - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_5/water_supply_engineering/requirements-good-pipe-material - Whole chapter: https://www.bctengineer.com/md/semester_5/water_supply_engineering/chapter-8 ## Question What are the requirements of a good pipe material? (What are the selection criteria of pipe materials in water supply system?) ## Short answer Good pipe material must withstand internal pressure and external loads, resist corrosion, have a smooth interior for low friction, be safe for water, and provide easy, watertight joining. Selection considers pressure, diameter, soil, water quality, terrain, cost, and local availability. ## Answer A pipe material for water supply should satisfy the following requirements. 1. **Strength:** withstands internal pressure, water hammer and external loads (soil, traffic). 2. **Durability:** long life, resistant to corrosion, chemical attack from soil and water, and to abrasion. 3. **Smooth interior:** high Hazen-Williams C value, low friction loss, and no growth of deposits. 4. **Safe for water:** no taste, colour, toxic or bacterial effect on the water carried. 5. **Easy joints:** watertight, flexible and quick to make. 6. **Light and easy to handle** and transport; available in many sizes and lengths. 7. **Low cost,** including laying and maintenance, and locally available. 8. **Easy to repair,** to tap for connections, and to extend later. #### Selection criteria in a water supply scheme - **Pressure and head:** the working pressure and the surge pressure decide the class (wall thickness) of pipe. Steel or DI is used for high pressure; PVC/HDPE for medium pressure. - **Water quality and soil:** aggressive soil or water favours plastic or lined pipes. - **Diameter and flow:** large diameters suit DI, steel or concrete; small diameters suit GI, PE, PVC or PPR. - **Terrain:** light flexible pipes (HDPE) suit hilly and landslide-prone ground; exposed crossings need GI or steel. - **Cost, availability and skill** for laying and repairs; **life** of the scheme. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. Why is a smooth interior (high C) desirable? A. It lowers friction loss B. It raises cost C. It increases weight D. It makes joints easier Answer: A. A high Hazen-Williams C gives low friction loss and no deposit growth. (Key point: Smooth interior) 2. 'Safe for water' means the material: A. Is cheap B. Is strong C. Gives no taste, colour, toxic or bacterial effect D. Is light Answer: C. The pipe must not harm the quality of water carried. (Key point: Safe for water) 3. What decides the class (wall thickness) of pipe? A. Colour B. Working pressure and surge pressure C. Length only D. Soil colour Answer: B. Working and surge pressures decide the pipe class. (Key point: Pressure criterion) 4. Which pipe suits hilly, landslide-prone ground? A. Concrete B. Cast iron C. Light flexible HDPE D. Brittle PVC exposed Answer: C. Light flexible pipes such as HDPE suit hilly and unstable terrain. (Key point: Terrain) ## Related in Water Supply Engineering - [Good pipe requirements; expansion joint](https://www.bctengineer.com/question.md?key=semester_5%2Fwater_supply_engineering%3Apipe-requirements-expansion-joint) — Water Supply Engineering, chapter 8, asked 2× - [Pipe material selection factors; PPR pipes](https://www.bctengineer.com/question.md?key=semester_5%2Fwater_supply_engineering%3Apipe-material-factors-ppr) — Water Supply Engineering, chapter 8 - [Objectives of supply; wholesome water requirements](https://www.bctengineer.com/question.md?key=semester_5%2Fwater_supply_engineering%3Aobjectives-requirements-wholesome) — Water Supply Engineering, chapter 1, asked 2× - [Pipe requirements; PE, PVC, PPR pipes](https://www.bctengineer.com/question.md?key=semester_5%2Fwater_supply_engineering%3Apipe-requirements-pe-pvc-ppr) — Water Supply Engineering, chapter 8 - [Pipe requirements; concrete, CI, PPR pipes](https://www.bctengineer.com/question.md?key=semester_5%2Fwater_supply_engineering%3Apipe-requirements-concrete-ci-ppr) — Water Supply Engineering, chapter 8 - [Typical water supply system and components](https://www.bctengineer.com/question.md?key=semester_5%2Fwater_supply_engineering%3Atypical-ws-system-components) — Water Supply Engineering, chapter 1, asked 4× ## Related in other subjects - [Good insulating material requirements and applications](https://www.bctengineer.com/question.md?key=semester_5%2Felectric_machine_design%3Ainsulating-requirements-application) — Electric Machine Design, chapter 1, asked 2× - [Short note: Water supply and distribution system](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Awater-distribution-short) — Building Technology, chapter 12, asked 2× - [Principles of laying out water supply system](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Awater-supply-principles) — Building Technology, chapter 12 - [Insulating material requirements and silicon steel](https://www.bctengineer.com/question.md?key=semester_5%2Felectric_machine_design%3Ainsulating-requirements-silicon) — Electric Machine Design, chapter 1, asked 2×