Key Criteria for Corrugated Pipe Diameter Selection
Corrugated pipe diameter selection is determined by the project's flow rate calculation, laying depth and soil conditions. Wrong diameter selection directly affects both cost and long-term system performance.
Standard Diameter Ranges and Application Areas
| Diameter (mm) | Application | Typical SN Class | Length (m) |
|---|---|---|---|
| 100 – 200 | Building plot connection, small drainage | SN4 / SN8 | 6.00 |
| 250 – 400 | Neighbourhood collector, roadside stormwater | SN8 | 6.00 |
| 500 – 600 | District collector, municipal main line | SN8 / SN16 | 6.00 |
| 700 – 1000 | Major city collector, HPP discharge | SN8 / SN16 | 6.00 |
| 1200 | Main collector, treatment plant inlet | SN8 / SN16 | 5.00 – 6.00 |
Flow Rate Calculation: Which Diameter is Sufficient?
Practical method: Expected flow rate (Q) in litres/second is determined and Manning formula is applied. At gravity slope of 0.3%, approximate values are:
- Ø200 mm: ~50 L/s capacity
- Ø300 mm: ~150 L/s capacity
- Ø400 mm: ~320 L/s capacity
- Ø500 mm: ~580 L/s capacity
- Ø600 mm: ~930 L/s capacity
Difference Between SN4 and SN8
SN4: No vehicle traffic, 0–3m laying depth, stable soil. Suitable for parks, gardens, farmland applications.
SN8: Under roads, areas with vehicle traffic, 3–6m laying depth or soils with groundwater. Standard choice for municipal projects.
SN16: Under heavy load roads, laying depth over 6m or special engineering projects.
Joining Systems
Socket (rubber seal): Most common system. Fast assembly thanks to rubber seal with tolerance for minor ground movements.
Plain end: Used at concrete manhole and inspection chamber connections where special adapters are required.