| Class |
Description |
Condition Normally Used |
| np1 |
Unreinforced concrete non-pressure Pipes. |
For drainage and irrigation use, above ground Orin shallow ranches. |
| np2 |
Reinforced concrete, light-duty, Non pressure pipes. |
For drainage and irrigation use, for culverts carrying light traffic. |
| np3 |
Reinforced concrete, heavy-duty, Non-pressure pipes. |
For drainage and irrigation use, for culverts carrying heavy traffic. |
| np4 |
Reinforced concrete, heavy-duty, Non-pressure pipes. |
For drainage and irrigation use, for culverts carrying very heavy traffic, such as railway loadings. |
| p1 |
Reinforced concrete, Pressure pipes, tested to a hydrostatic pressure of 2-0 kg/cm2 ( 20 m head ) |
For use on gravity mains, the design pressure not exceeding two-thirds of the test pressure. |
| p2 |
Reinforced concrete, Pressure pipes, tested to a hydrostatic pressure of4-0 kg/cm2 ( 40 m head ) |
For use on pumping mains, the design pressure not exceeding half of the test pressure. |
| p3 |
Reinforced concrete, Pressure pipes, tested to a hydrostatic pressure of 6-0 kg/cm2 ( 60 m head ) |
For use on pumping mains, the design pressure not exceeding half of the test pressure. |
