Product Classification

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.