Comparison of PVC and Ductile Iron Pipe
Material Properties of PVC and Ductile Iron
The material properties of PVC make PVC a better choice than Ductile Iron for many applications. The following table lists the properties for both PVC and Ductile Iron that are most important to the design of piping systems:
| Property | Specification | PVC | Ductile Iron |
|---|---|---|---|
| Tensile Strength (PSI) | ASTM D-638 | 7,000 | 60,000 |
| Specific Gravity | ASTM D-1505 | 1.40 | 7.1 |
Pressure Class Comparison
| PVC | Ductile Iron | ||
|---|---|---|---|
| Dimension Ratio | Pressure Rating | Pressure Class | Pressure Rating |
| DR 18 | 235 PSI | 350 | 350 PSI |
| DR 21 | 200 PSI | 300 | 300 PSI |
| DR 25 | 165 PSI | 250 | 250 PSI |
| DR 32.5 | 125 PSI | 200 | 200 PSI |
| DR 41 | 100 PSI | 150 | 150 PSI |
| DR 51 | 80 PSI | 100 | 100 PSI |
Sample Pipe Comparisons
- Horizontal Directional Drilling
Fusible PVC™ will require a smaller bore hole diameter than other pipe systems. A smaller bore-hole diameter means that there will be less back reaming, less drilling mud, and less spoil disposal. The following comparisons illustrate these advantages.
- Jack and Bore
The larger outside diameter of Ductile Iron pipe requires casing sizes to be larger in jack and bore applications. Fusible PVC™ can utilize smaller casings, which ultimately lead to lower material and installation costs. In addition, Ductile Iron requires the use of casing spacers, which are not a requirement for Fusible PVC™.
- Direct Bury / Open Cut
Fusible PVC™ will require a more narrow trench width for direct bury than Ductile Iron Pipe, due to the larger outer diameter on the Ductile Iron Pipe. A smaller trench volume means that there will be less excavation, less backfilling and less spoil disposal. The drawing below illustrates these advantages.