How many feet of water correspond to 1 psi?

• A. 1.5'
• B. 2.31'
• C. 3.14'
• D. 4.0'

Answer: (B)

To understand why 2.31 feet of water corresponds to 1 psi, one must consider the relationship between pressure and fluid height. Pressure in a fluid is determined by the height of the fluid column exerting the force due to gravity. The equation for pressure due to a column of liquid can be expressed as:

[ P = \rho g h ]

where:

• ( P ) is the pressure in pounds per square foot (psi is pounds per square inch, which can also be converted to pounds per square foot),

• ( \rho ) is the density of the fluid (for water, this is typically about 62.4 lb/ft³),

• ( g ) is the acceleration due to gravity (approximately 32.2 ft/s²),

• ( h ) is the height of the fluid column in feet.

When calculating the height of a water column that produces 1 psi, we can manipulate the equation. For 1 psi, the conversion involves recognizing that 1 psi equals 144 pounds per square foot (since there are 144 square inches in a square foot). By rearranging the formula and substituting known values for the density and gravity of water, we can derive that:

1 psi is