Centrifugal pumps work by having a propeller or an impeller rotate to generate centrifugal force. The result of the centrifugal force is a low-pressure area at the center of the rotation and a high-pressure area at the edge of the rotation. The low-pressure area at the center of the rotation is what causes the liquid to flow into the pump (fluids tend to move from high pressure to low pressure). When we work with various chemicals with different physical properties, we need to understand if the chemical could vaporize at the low-pressure area of the pump. To make that determination, we calculate the Net Positive Suction Head available value (NPSHa) of the pump system and compare it with the Net Positive Suction Head required (NPSHr) of the pump. Please contact your pump manufacturer if you need assistance with determining the NPSHa value of your system.