I was seeing two of everything Roland, having raised a glass or two in remerberance. I was still interested in seeing what a Discharge TC Member was seeing on this very same matter. But that was Nov. 5, and this is now, and I've given up on it.
Except to say, Sean, I'm about 75% sure a formal interp. from NFPA says that if a manufacturer has a published equivalent length for a fitting, even if the sprinkler is screwed directly into it, you need to include it. ~35 years ago, before The Handbook Commentary, I was told, by the inventor of The Hose Monster no less*, that the reason we can exclude that fitting is that when the Coefficient of Discharge for sprinklers were being established they were directly screwed into fittings, sooo... Steve L. wonders that mech tees might have been around since-- 1940? That's probably close since Victalic is short for Victory Through Hydraulics. Anyway, if a 1" outlet mech tee is 8' eql, and a 1" tee is 5' eql, I would play like there was a three foot sprig if I was using a mech tee for the head connection. If it was a bl connection, you would use 8 instead of 5, right? That's a 3 foot diff. *he even told me how and when he got the idea; he was boarding a plane, to Cleveland (sorry about game 7 Vince) thinking about Bernoulli. Brad On Nov 10, 2016 2:41 PM, "Roland Huggins" <[email protected]> wrote: > It depends on your tolerance to a really mad PRIOR customer. > > The standard allows designing to the curve (never a good idea) so the > original spec installation would comply with 13. IF the future > modification is required to be calculated, I can’t imagine a glowing > recommendation will follow. > > It will be interesting too see what others are seeing. > > Roland > > > Roland Huggins, PE - VP Engineering > American Fire Sprinkler Assn. --- Fire Sprinklers Saves Lives > Dallas, TX > http://www.firesprinkler.org > > > > On Nov 10, 2016, at 9:50 AM, [email protected] wrote: > > All, > > A couple weeks ago the topic of hydraulic loss through Mech Tee’s was > brought up. I was in agreement with most of the forum that the mech tee > counts as a “fitting” and per the exceptions of NFPA 13, the fitting the > sprinkler is attached to can be excluded from the calcs. > > That got me thinking (which can be dangerous), how do you treat the > scenario of attaching the sprinkler into a reducing bushing which is then > screwed into a welded outlet or threaded tee. This is done all the time > for a spec office or warehouse that has the potential for a future TI build > out. If I want to take the code literally, I would ignore the loss in the > bushing since that is the fitting the sprinkler is attached to. However, I > would then need to add a short section of 1” pipe with a tee into my calc > because it isn’t directly attached. For a spec office this isn’t that big > of a deal as the change is minimal and probably forgettable based on all > the other safety factors and constructability. However, if for whatever > reason you are screwing a ¾” thread ESFR into a 1” outlet, the loss can be > substantial. > > I was wondering how other people have treated this scenario. Never > thought of it, ignore it, account for it, assume screwed fittings directly > attached to each other equals “fitting” for NFPA 13 applications, etc. > > Thanks, > Sean VG > > > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler. > org > > > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler. > org > >
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