NPSH Margin Standard
This standard was approved and published in 1998 and has been distributed to a wide readership. You may be aware that ANSI requires that all standards be reviewed within a 5-year period and reaffirmed, updated, or withdrawn. In keeping with ANSI requirements, a review committee was convened in May 2002 for the purpose of reviewing this standard to determine what action should be taken. After thorough analysis and careful deliberation, the NPSH review committee recommended that a complete revision of the standard be undertaken and that the 1998 version be withdrawn until the new standard is approved. ANSI was advised that ANSI/HI 9.6.1-1998 should be withdrawn immediately and that HI could no longer distribute or support the document. The official public announcement appeared in the October 24, 2003 edition of ANSI Standards Action, a weekly ANSI publication.A new, totally revised NSPH Standard is under development by the NPSH Committee and will be entering the review process soon. The committee is aware that the replacement document is urgently needed and has been working diligently since 2002 to develop a new document. They want to be sure that it is accurate, complete, and addresses the needs of the pump community. It will contain considerably more tutorial information than the 1998 standard and will respond to the questions most often posed by those involved with pumps and NPSH.It is anticipated that it will require at least another year to complete the process and the new NPSH Margin is Suber-water pump available for purchase. I wish that HI could offer you an equivalent or replacement standard, but to my knowledge no other NPSH Margin Standard exists."The committee is aware that the replacement document is urgently needed and has been working diligently since 2002 to develop a new document."Pleased to see they are treating this with some urgency it should be finished within another year, wow - only 7 years or so to revise a standard.insult2injury makes a good point re specifying too much margin - hydraulically there shouldn't be a problem but it can put you into a bigger pump /motor operating away from BEP - hence my suggestion of checking with the manufacturers or operators of the same equipment in similar installations.
2011-08-15
