What is the relationship of psi to feet of water head?

• A. 1 psi = 1.5'
• B. 1 psi = 2.31'
• C. 1 psi = 3.0'
• D. 1 psi = 4.0'

Answer: (B)

The relationship between psi (pounds per square inch) and feet of water head is derived from the density of water and the effects of gravity. Specifically, one psi equals the pressure exerted by a column of water that is approximately 2.31 feet high. This conversion factor is based on the weight of a water column: since the density of water is about 62.4 pounds per cubic foot, a height of 2.31 feet of water generates a pressure of 1 psi at the base of that column.

This means if you measure the pressure exerted by a water column, you can convert that pressure into an equivalent height of water in feet. The value of 2.31 feet is crucial for engineering applications that involve fluid mechanics and hydraulics, making it essential for understanding pressures in systems involving water, like municipal water supply, stormwater management, and irrigation systems.

Other options do not reflect the correct conversion factor for psi to feet of water head and stem from misunderstandings of fluid pressure principles or incorrect applications of density.