The Hydraulic Institute (HI) has updated the 1997 edition of the ANSI/HI standard on allowable operating region for centrifugal and vertical pumps and published ANSI/HI 9.6.3 – 2012 Rotodynamic (Centrifugal and Vertical) Pumps – Guideline for Allowable Operating Region.

The updated guideline discusses the effects of operating a rotodynamic pump at rates of flow greater than or less than the rate of flow at the pump’s best efficiency point (BEP). These effects influence the power consumption and life of pump components and, therefore, considering the operating rate of flow is essential to reliable, efficient pump operation.

The preferred operating region (POR) and the allowable operating region (AOR) are defined for rotodynamic pump types and related to specific speed.  Factors that affect AOR are discussed and NPSH margin versus rate of flow is presented.

The guideline also indicates when stable or unstable operation may be expected based on typical system head curves, for pumps exhibiting a drooping head curve or a head curve with a dip.  Considerations such as the robustness of a pump are also discussed.

The guideline is available for purchase at the HI eStore for $65.00 and is available in both hardcopy and pdf formats.

About the Hydraulic Institute: The Mission of the Hydraulic Institute is to serve the pump industry as a forum for the exchange of information while providing value-added services to member companies and pump users worldwide. This includes the development and delivery of comprehensive industry standards. For more information on the Hydraulic Institute, its member companies and its Standards Partners, visit www.Pumps.org.  For information on its educational offerings visit the Pump Systems Matter website at www.PumpSystemsMatter.org.