NPSH stands for Net Positive Suction Head Available. Which of the following best reflects this statement?

• A. Net Positive Suction Head Available is correct
• B. Net Positive Suction Head Required is correct
• C. Net Positive Suction Head Reduction is correct
• D. Net Pressure Suction Head Available is correct

Answer: (A)

NPSH is a measure used to prevent cavitation in pump systems, and it stands for Net Positive Suction Head Available. The “Available” part refers to the actual head that is present at the pump suction—how much energy of the liquid is available to resist vaporization, typically expressed in meters or feet of liquid. This available head must be compared to the minimum head the pump requires to avoid cavitation (NPSH Required). If the available head is sufficient, cavitation is unlikely; if not, cavitation can occur. The correct expansion uses “Available” and “Positive,” not “Required,” “Reduction,” or “Pressure.”