How many feet of water can a perfect vacuum at sea level theoretically raise in a pipe?

A perfect vacuum at sea level can theoretically support a column of water measuring approximately 34 feet. This is based on the atmospheric pressure exerted at sea level, which is around 14.7 pounds per square inch (psi).

To understand how this conversion works, it’s important to consider the relationship between pressure and the height of a liquid column. In a perfect vacuum, no air pressure exists to exert force down on the water, allowing atmospheric pressure to push the water up the column. The standard calculation used is that 1 psi can support approximately 2.31 feet of water. When you calculate the height of water a perfect vacuum can raise, you take the total atmospheric pressure (14.7 psi) and multiply it by 2.31 feet per psi, leading to the figure of around 33.96 feet. This is commonly rounded off to 34 feet.

This fundamental principle illustrates why the correct answer is 34 feet, as it reflects the maximum height that water can be raised by a vacuum at sea level under ideal conditions. Understanding this concept is crucial for anyone involved in backflow prevention and the behavior of water systems, as it relates directly to pressure dynamics and fluid mechanics.