Most engineers select a pump based on its Head-Capacity curve. Yet, that curve is only valid under ideal suction conditions (ANSI/HI 9.6.1). In the real world, the intake structure dictates whether the pump will ever see those ideal conditions.
The cost of ignoring ANSI/HI 9.8:
ANSI/HI 9.8 provides the mathematical and geometric framework to eliminate these risks before concrete is poured or steel is cut.
A single pump is easy. When you put two or more pumps side-by-side, the hydraulics interact. HI 9.8 mandates:
About the Author: This article is intended for civil, mechanical, and chemical engineers involved in water/wastewater, power generation, and industrial pumping systems. Always consult a licensed hydraulic engineer for final design verification.
The ANSI/HI 9.8 Rotodynamic Pumps for Pump Intake Design is a definitive industry standard developed by the Hydraulic Institute (HI) to ensure that the flow of liquid into a pump is uniform, steady, and free from hydraulic disturbances. Proper intake design is critical because poor hydraulic conditions can lead to reduced efficiency, excessive vibration, and premature mechanical failure. Core Objectives of ANSI/HI 9.8
The primary goal of the standard is to provide engineers and contractors with a foundation for developing functional and economical pumping facilities. Key objectives include: ansi hi 9.8 rotodynamic pumps for pump intake design
Uniform Flow: Ensuring liquid enters the impeller eye at a steady velocity profile.
Vortex Prevention: Minimizing surface and sub-surface vortices that can entrain air or cause cavitation.
Optimal Performance: Reducing the risk of swirl and air ingestion, which can significantly decrease hydraulic efficiency. Scope and Applications
The standard covers a wide range of intake structures for both clear and solids-bearing liquids:
Intake Types: Includes rectangular intakes, formed suction intakes (FSI), trench-type intakes, circular pump stations, and unconfined intakes.
Pump Configurations: Applicable to vertical turbine pumps (can-type), barrel pumps, and suction tanks. Most engineers select a pump based on its
Market Use: Widely used in municipal water/wastewater, petrochemical, and power plant cooling systems. Key Design Criteria and Acceptance Standards
To achieve an "acceptable" design, the standard outlines specific measurable criteria, often verified through physical model studies or Computational Fluid Dynamics (CFD): Vortex Control at Pump Intake Using Double
The ANSI/HI 9.8-2024 standard, titled Rotodynamic Pumps for Pump Intake Design, is the definitive American National Standard for engineering efficient, reliable pump stations. Developed by the Hydraulic Institute (HI), this standard provides the technical framework for designing new intakes and modifying existing ones to ensure optimal hydraulic performance. Core Objectives of ANSI/HI 9.8
The fundamental goal of the standard is to ensure that flow reaching the pump impeller is uniform, steady, and free from swirl or entrained air. Poorly designed intakes often lead to:
Reduced Efficiency: Non-uniform velocity distributions at the pump suction can significantly lower hydraulic performance.
Mechanical Damage: Problems like cavitation, high vibration, and noise can cause premature mechanical seal and bearing failures. ANSI/HI 9
Operational Issues: Formation of surface or submerged vortices and excessive pre-swirl can lead to air entrainment and performance drop-off. Standard Intake Configurations
ANSI/HI 9.8 defines specific geometries for several common intake types. Adhering to these "standard" designs often eliminates the need for expensive physical testing. ANSI/HI 9.8-2018 - Rotodynamic Pumps for Pump Intake Design
ANSI/HI 9.8 is more than a document; it is an insurance policy. A pump that costs $100,000 can destroy itself in months if fed by a $50,000 sump designed without HI 9.8. Conversely, a compliant intake structure costing $150,000 will allow that pump to run for 25 years at 90% efficiency.
Key takeaways for the engineer:
By adhering to ANSI/HI 9.8 Rotodynamic Pumps for Pump Intake Design, you don’t just build a sump; you build a hydraulic foundation that lets your pump perform as the manufacturer intended.