Corrugated metal pipes selection guide: compare SN ratings, material grades (galvanized/316L), and application cases. Includes ASTM/ISO standards reference.
1. Core Selection Parameters
Mechanical Properties
- Ring Stiffness Class
SN2 (Light duty) / SN4 (Standard) / SN8 (Heavy duty) per ISO 10380
Typical Use: SN8 for >3m soil cover or dynamic loads - Axial Load Capacity
Modified Terzaghi Formula:
qa = cNc + γDNq + 0.5γBNγ
Where γ=soil unit weight, B=pipe diameter - Fatigue Life
ASTM A796 dynamic load testing standard (Minimum 1M cycles)
Environmental Compatibility
- Soil Corrosivity
NACE TM0169 Class C5 (severe) to Class C1 (mild) - Hydrogeological Factors
Water table depth + freeze-thaw cycles/year - Chemical ResistancepH RangeCl⁻ ConcentrationRecommended Material<4Any316L Stainless Steel4-9>200ppmGalfan Coated (Zn-5%Al)4-9≤200ppmHot-dip Galvanized (600g/m²)
Manufacturing Specifications
- Corrugation Patterns
Ω-type (Higher stiffness) vs Spiral (Better flexibility) - Joint Types
Flanged (ASTM A798) vs Socket (ASTM A807) leakage test data - Coating Economics
Cost comparison: Hot-dip Zn (1x) < Al-Zn Alloy (1.5x) < Polyurethane (2.3x)
2. Decision Tree Algorithm
graph TD
A[Design Load] -->|Static| B[SN4 Standard]
A -->|Dynamic| C[SN8 Heavy-duty]
B --> D{Corrosion Environment}
C --> D
D -->|pH<4| E[316L Stainless]
D -->|Cl⁻>200ppm| F[Galfan Coating]
D -->|Normal| G[Standard Galvanized]3. Application Case Studies
Highway Culvert (USA)
- Parameters: AASHTO HS20 loading + 50-year lifespan
- Solution: SN8 Spiral Pipe + 600g/m² Zn coating
Mine Drainage (Chile)
- Parameters: pH3.5 acidic water + 15m overburden
- Solution: 3mm 316L Stainless Steel Pipe
Agricultural Irrigation (India)
- Parameters: Seasonal use + 5m hydraulic head
- Solution: SN4 Ω-type Pipe + 200g/m² Zn coating
Compliance Standards Quick Reference
- ASTM A760 (Material)
- EN 10219 (EU Testing)
- GB/T 12777 (China)
