• Rotodynamic Pumps Guideline for NPSH Margin (ANSI/HI 9.6.1-2017 - secure PDF)

click on thumbnail to zoom
Item #: B118e
Member Price: $67.50
Non-member Price: $90.00

Product Notes

Discounts will be applied in the shopping cart. Please sign in with your company email to get member price.

Description  more details

Scope of Standard: Today’s higher speed, higher energy density pumps might not achieve acceptable service life without an adequate NPSH Margin that ensures pumps operate without excessive vibration and cavitation. ANSI/HI 9.6.1 serves as a guideline for NPSH margin for rotodynamic pumps with absorbed power levels up to 5300 hp and impeller tip speeds less than 130 feet per second. The purpose of this guideline is to establish recommended net positive suction head available (NPSHA) above the published NPSH required (NPSHR) that will lead to acceptable pump performance and service life.

What You Will Learn/Overall Benefits:

  • Understand why it is essential to specify an appropriate NSPH Margin
  • Know requirements of pump design to ensure performance (i.e. pumps sensitive to water react differently in cold water vs. oil)
  • Learn about the negative aspects of specifying an excessive NPSH Margin

Applicable Markets:  This standard applies to all markets worldwide. Specific recommendations are provided for the following applications:

  • Petroleum (hydrocarbon) process pumps
  • Chemical process pumps
  • Electric power plant (non- nuclear) pumps
  • Nuclear power plant pumps
  • Water/wastewater pumps
  • Pulp and paper stock pumps
  • Building services
  • Slurry pumps
  • Oil and gas industry pumping applications
  • General industrial pumping applications

Click the "More Details" tab above for additional product information.


ISBN: 978-1-935762-57-7
Pages: 30
Approval Date: 2017
Table of Contents: View in PDF format
Also Available in Hardcopy: View now

Content:  NPSH definition, NPSH margin considerations related to inlet tip speed, larger impeller eye, suction specific speed, impeller vane overlap, pump size, construction materials and duty cycle, change in NPSHA with time, rotative speed limitations in water/ wastewater pumps.

Who Should Buy This Standard:  OEMs, specifiers, end users and engineering consulting companies that should know requirements of pumps to ensure long-term performance.

New Content in 2016 Version:

  • Updated definitions
  • More NPSH margin consideration factors
  • Removed Rotative speed limitations, water and wastewater pumps content from Appendix A to its own appendix

Important Notice: 

This standard is available for immediate download in secure PDF format. Standards in this format are a single-user license and are encrypted for security purposes. Each standard is authorized to a single login and password on a single desktop or laptop computer. The end-user license prohibits installation of these files on a network server or their shared use in a network environment.  These files may be transferred from an old computer to a new computer by following the instructions provided upon purchase or available online at estore.pumps.org/about.aspx.

To view HI Standards in this format requires the download of the free Adobe® Reader®. Authorization requires download of an Adobe-approved plug-in from FileOpen Systems, Inc. and Internet access to complete the authorization process. Security permissions of these files allow printing and the addition of comments. Once authorized these files may be accessed with or without connection to the Internet.


Be the first to submit a review on this product!
Review and Rate this Item


Email A Friend

Send your friend a link to this product.