What is the expected pressure loss per 4 feet of height difference in an irrigation system?

In irrigation systems, the concept of head loss due to elevation changes is critical for understanding how pressure varies with changes in height. The standard rule of thumb in many irrigation designs is that for every foot of vertical rise (or drop), there is an approximate pressure loss or gain of about 0.43 PSI (pounds per square inch).

To determine the expected pressure loss per 4 feet of height difference, you would multiply the pressure loss per foot by the number of feet:

0.43 PSI/foot × 4 feet = 1.72 PSI.

Rounding this to a more practical value commonly used in irrigation design leads to the answer of approximately 1.7 PSI for a 4-foot height difference. This value is widely accepted among landscape architects and irrigation contractors as it provides a reasonable approximation for system calculations, ensuring adequate pressure for efficient system function. By selecting this answer, it shows an understanding of how elevation impacts hydraulic performance in irrigation systems.