The control setpoints for the operation of High Purity Water Systems are selected to ensure water quality and to meet business needs. System qualification testing criteria are often set at levels that contribute to higher operating expense and lead to investigations if the levels are not maintained consistently.

A case study will be presented that shows how a risk based analysis of User Requirements will result in setpoint selections that will maintain system quality and reduce operational costs. The system will be challenged under worst case conditions during qualification to ensure that when the system is operational, fluctuations in the operating parameters are proven not to affect quality which will minimize system investigations.