I remember from my AFSA (Old School) design training course, that threads and engagements are tapered.
3 exposed is set as a nominal number. For 1" pipe, the actual number left showing is 2 7/8.-ish It is based on threads per inch, along a taper. Reference the ASTM standards for exact numbers. R/ Matt -----Original Message----- From: Sprinklerforum <sprinklerforum-boun...@lists.firesprinkler.org> On Behalf Of Matt Grise via Sprinklerforum Sent: Wednesday, January 5, 2022 7:42 AM To: sprinklerforum@lists.firesprinkler.org Cc: Matt Grise <m...@afpsprink.com>; Kevin Hall <kh...@firesprinkler.org> Subject: RE: Thread connection holding on one thread only If I recall from my book-learning days, there is a pretty well established minimum thread engagement that provides the full strength of a threaded connection. (maybe 3?). That may also only apply to bolts though. Matt -----Original Message----- From: Sprinklerforum <sprinklerforum-boun...@lists.firesprinkler.org> On Behalf Of Kevin Hall via Sprinklerforum Sent: Wednesday, January 05, 2022 8:33 AM To: sprinklerforum@lists.firesprinkler.org Cc: Kevin Hall <kh...@firesprinkler.org> Subject: Re: Thread connection holding on one thread only I do not believe one is sufficient. I recall a project where the specification limited the maximum number of exposed threads to 2 or 3. I'd have to do some research to find the product/installation standard that was referenced. Kevin Hall, M.Eng., P.E., ET, CWBSP, PMSFPE Coordinator, Engineering and Technical Services American Fire Sprinkler Association kh...@firesprinkler.org 214-349-5971 On Wed, Jan 5, 2022 at 2:16 AM Dan Arbel via Sprinklerforum < sprinklerforum@lists.firesprinkler.org> wrote: > Dear Forum Members > > I have a case where 1.25" NPT pipe nipple was connected to 1.25" BSP > (as per British standard) pipe. > > Sprinkler System in interstitial space. > > There was only 2 threads engagement. > > After about 15 years somebody touched the a pipe and the connection > disengaged. > > I would appreciated the members opinion on the allegation that even > one thread engagement is sufficient providing sufficient strength. > > Dan Arbel > Dan Arbel Risk Engineering Ltd > Mail: d...@riskmanage.com > WEB SITE: > https://linkprotect.cudasvc.com/url?a=https%3a%2f%2fwww.riskmanage.com > &c=E,1,rOBCJWaUiWX-Zi-j03j48v-ojODJ4zDjCTCn-XcTQUWSVSZzQRanv2vrdqlUogX > nkOECEYOqMT2eMuzN6PVEfyuVyVF6Hoz4BiV1VyGvBRCcljgZH2U,&typo=1 > Mobile: +972-52-6611337 > Tel: +972-4-8243337 > _______________________________________________ > Sprinklerforum mailing list > Sprinklerforum@lists.firesprinkler.org > > https://linkprotect.cudasvc.com/url?a=http%3a%2f%2flists.firesprinkler > .org%2flistinfo.cgi%2fsprinklerforum-firesprinkler.org&c=E,1,RvPpy3ldS > C8kzu280ouAOq2QKBzNGfMu7REiocN-XOdCtouKzXB4EaUtnbHa1UoPns-R2H1fzQj-fW- > oIX3YW0Doh9ZL84fg3cNaQ0q1OQ,,&typo=1 > _______________________________________________ Sprinklerforum mailing list Sprinklerforum@lists.firesprinkler.org https://linkprotect.cudasvc.com/url?a=http%3a%2f%2flists.firesprinkler.org%2flistinfo.cgi%2fsprinklerforum-firesprinkler.org&c=E,1,wikZY07kLJSV87o86Ivs1Jsxm4l75jKdQbbfbZ7tVZifvQRGY33Wh20_IAQ7wACFTF9yFLpxM-xqELTjxDST6UJ7dCl0WTqJP_LkvfP8qA,,&typo=1 _______________________________________________ Sprinklerforum mailing list Sprinklerforum@lists.firesprinkler.org http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list Sprinklerforum@lists.firesprinkler.org http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
