How to Calculate Buoyancy for a Pipe

By Naeem Ahmed; Updated April 24, 2017
Ships stay afloat on large bodies of water due to the water's buoyant force.

Buoyancy refers to the upward force experienced by an object in a fluid, such as water. In water this force is proportional to the water displaced by the object. If this force is higher than the weight of the object, the object will float on the water. This effect allows the construction of boats and ships, which float even when they are made of heavy metals. The buoyancy of a pipe can be calculated using its diameter and length.

Multiply the outside pipe diameter in feet by itself using a calculator and call it "D." Assuming the diameter to be 1.5 feet, D = 1.5 X 1.5 = 2.25.

Multiply "D" with 62.4 (the weight of water in pounds-per-cubic-foot) and call it "D1." For the example being considered, D1 = D X 62.4 = 2.25 X 62.4 = 140.4.

Multiply "D1" with 0.78 (the percentage of the pipe which is submerged in the water) and call it "W." For the example being considered, W = D1 X 0.78 = 140.4 X 0.78 = 109.51.

Multiply "W" with the length of the pipe to get the required buoyant force in pounds. Assuming the length of the pipe to be 5 feet, the force will be F = W X 5 = 109.51 X 5 = 547.55 pounds.

About the Author

Naeem Ahmed has been an established author of technical literature since 1989. He has numerous publications to his credit in peer-reviewed research journals such as "Physical Review Letters" and "Nuclear Instruments and Methods in Physics Research." With a Ph.D. in physics from Siegen University in Germany, he is an active researcher and academic.