Andy, I have never seen anything in writing about the number of exposed threads of a bolt thru the nut. However, I used to be an aircraft mechanic in the Navy, and we had a rule of two exposed threads. We lived by that rule, where it came from we never questioned. It worked in conditions of vibrations that a fire pump would never experience. Probably came from some design engineer in the third basement of Boeing during WWII. It is amazing how some rules get hatched and live forever, only to be expanded upon as if the original came down from Mt. Sinai. John O'Connor National Fire Sprinklers, Inc. Nashville TN
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Andy Sent: Monday, May 13, 2013 3:05 PM To: [email protected] Subject: Exposed threads I was told that bolts on a fire pump must have 3 threads showing on the bolt side I complied and then was told I must have 5 exposed threads because it will operate above 150 PSI I complied but I did ask were to find that. I love code trivia I was told its some were in the ASME codes that are referenced In front of NFPA 20. I do not have a copy of these. I pleats try to meet the FM request But..... Thank you, in advance. Andy Johnston _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org ----- No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1432 / Virus Database: 3162/5820 - Release Date: 05/13/13 _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
