Pipe Type:
Pipe Outside Diameter:
DR or PS:

This is the specific gravity of the fluid that is surrounding the outside of the empty pipe backfilled with soil at the specified unit weight only.
  • Groundwater = 1.0
  • Seawater = 1.028

lbs/Ft3 κμ Material
100 0.1650 Dry Sand
115 0.1650 Ordinary (damp) Sand
120 0.1650 Wet Sand
120 0.1300 Damp Clay
130 0.1100 Saturated Clay
115 0.1500 Saturated Topsoil
100 0.1650 Sand & Damp Topsoil
105 0.1924 Granular Materials Without Cohesion
Your Value

P = vertical soil pressure due to the prism load, psi.

The prism load represents the maximum soil load on flexible pipe.

This value is used to determine the buoyancy of the pipe when grouting inside a casing or backfilling with Flowable fill in poor soil conditions.




Buoyancy Force (pounds) per foot length of pipe
Buoyancy Force (pounds) per foot length of pipe if the pipe is full of water
Minimum Soil Cover in feet (pipe empty) to prevent floatation
Maximum concrete or flowable fill lift height in inches (pipe % full of water) to prevent floatation