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 <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] > <mailto:[email protected]> > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org > <http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org>
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