A net positive suction head (NPSH) margin may be required for several reasons related to pump performance and service life, to cover the uncertainties of what the NPSH available (NPSHA) will be over the range of operation, and to provide for adequate pump reliability and performance. The purpose of this guideline is to establish margins over NPSH3 that will lead to acceptable pump performance and service life.

Individuals and organizations in North America affected by this document are asked to contact HI. These include pump users and specifiers, producers, standards developers, government agencies, and general interest groups. To participate, contact Karen Anderson, administrator, technical affairs, at kanderson@Pumps.org or call +1 (973) 267 9700 x123.

HI Pump Standards are references for anyone involved in pumps, including users, consultants, contractors, construction firms, manufacturers of pumps, seals, motors, instrumentation, controls, and pump software developers and systems integrators. HI periodically introduces new Standards based on industry needs.