---
title: "Pipe requirements; concrete, CI, PPR pipes"
subject: "Water Supply Engineering"
chapter: 8
key: "semester_5/water_supply_engineering:pipe-requirements-concrete-ci-ppr"
source: https://www.bctengineer.com/q/semester_5/water_supply_engineering/pipe-requirements-concrete-ci-ppr
site: BCT Engineering
---

# Pipe requirements; concrete, CI, PPR pipes

Water Supply Engineering · Chapter 8: Conveyance of Water

- Asked in: 2071 Shrawan, 4 marks
- Video: [TYPES OF PIPES USED FOR CONVEYANCE | VALVES | Environmental Engg | Public Health Engg.](https://www.youtube.com/watch?v=TH1ZZF22N-8) — SIMPLIFIED CIVIL AND GEOTECHNICAL ENGINEERING
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_5/water_supply_engineering/pipe-requirements-concrete-ci-ppr
- Whole chapter: https://www.bctengineer.com/md/semester_5/water_supply_engineering/chapter-8

## Question

Write down the requirements of good pipe material. Describe briefly concrete pipe, C.I pipe and PPR pipe.

## Short answer

Requirements: strength, durability, smoothness, safety, easy joints, light weight, low cost, repairability. Concrete pipes are cheap in large diameters, heavy, may leak. CI pipes are strong, durable 100 years, resist corrosion, heavy, brittle, prone to tuberculation. PPR pipes are light, corrosion-free, heat-fusion joints, handle hot water up to 95°C, non-toxic.

## Answer

#### Requirements of a good pipe material
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.

#### Concrete pipe
- Plain, reinforced (RCC) or prestressed pipes, made in sizes from about 150 mm up to 2–3 m; they are economical mainly in large diameters.
- Merits: cheap in large diameters, long life, does not corrode, can be cast locally, smooth interior.
- Demerits: heavy, difficult to transport and lay, may leak at joints, can be attacked by acids and sulphates, and cracks under tension and shock; used for large gravity mains and low-pressure lines (up to about 60 m head, more for prestressed).

#### Cast iron (CI) pipe
- Strong, durable (100 years), resists corrosion, stands high pressure and loads; the socket-spigot or flanged joints are easy.
- Heavy, costly, brittle; the interior roughens (tuberculation) so cement lining is provided.

#### Polypropylene random copolymer (PPR) pipe
- Light plastic pipe, joined by heat fusion to make a leak-free joint; resists corrosion and scaling; handles hot water up to 95 °C; non-toxic and long lived.
- Costly, needs fusion machine, expands on heating; not for large diameters.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Concrete pipes are suited to:
   A. Small hot water lines
   B. House connections
   C. Large gravity mains and low-pressure lines (300 mm and above)
   D. High-pressure small lines
   Answer: C. Concrete is cheap in large diameters, used for large gravity and low-pressure mains. (Key point: Concrete pipe use)

2. A demerit of concrete pipes is:
   A. Very light
   B. Heavy, may leak at joints and attacked by acids and sulphates
   C. Corrodes like steel
   D. Very small sizes only
   Answer: B. They are heavy, hard to lay, can leak at joints and be attacked by acids and sulphates. (Key point: Concrete demerit)

3. Why is cement lining provided in CI pipes?
   A. To make them lighter
   B. To make them cheaper
   C. To reduce roughening of the interior (tuberculation)
   D. To colour water
   Answer: C. CI interiors roughen with age, so cement lining protects capacity. (Key point: CI tuberculation)

4. How is PPR jointed and why?
   A. By lead caulking
   B. By flanges
   C. By solvent cement
   D. By heat (socket) fusion, giving a leak-free joint
   Answer: D. Heat fusion makes a leak-free joint, but needs a fusion machine. (Key point: PPR joint)

## Related in Water Supply Engineering

- [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 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
- [Requirements of a good pipe material](https://www.bctengineer.com/question.md?key=semester_5%2Fwater_supply_engineering%3Arequirements-good-pipe-material) — Water Supply Engineering, chapter 8, asked 2×
- [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 factors; CI vs steel](https://www.bctengineer.com/question.md?key=semester_5%2Fwater_supply_engineering%3Apipe-material-factors-ci-steel) — Water Supply Engineering, chapter 8
- [Short note: GI and CI pipe](https://www.bctengineer.com/question.md?key=semester_5%2Fwater_supply_engineering%3Agi-ci-pipe-note) — Water Supply Engineering, chapter 8

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