Yeah, I've done it before but wanted to see if I had been doing it correctly. I don't like to hydraulically calculate a pipe scheduled system as I've often seen the calcs bust causing even more headache for everyone when it's not necessary if the pipe scheduled 'hand calc' method works - not to mention they're two totally different sizing methods. As it turns out this particular project is busted by both the pipe scheduled 'hand calc' method and hydraulic calculation method so it's become a non issue - the owner will have to modify his system in order to reduce friction loss to the point where it can be retrofitted with a backflow preventor.
<https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=icon> Virus-free. www.avast.com <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=link> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> On Wed, Apr 14, 2021 at 12:36 AM Fpdcdesign via Sprinklerforum < [email protected]> wrote: > > > > I have done a few of these. I am not sure about 2019, but 2016 main and > appendix describe how to do this. You are pretty much in the right track > > > > > > > > > > > > On Apr 13, 2021 at 6:51 PM, <J H via Sprinklerforum (mailto: > [email protected])> wrote: > > > > > > > > Any takers? Does anyone retrofit backflows onto pipe scheduled systems? > On Mon, Apr 12, 2021 at 2:43 PM J H <[email protected] (mailto: > [email protected])> wrote: > Hello All, > We're > retrofitting a double check into an existing pipe scheduled system. > In > looking at NFPA 13 (2019) edition 19.3.2.1 in order to do this we just > > need a hydrant flow test and then subtract the friction losses of the > > double check and the friction loss due to elevation of the highest > > sprinkler from the flow test and make sure the leftover pressure is > greater > than the value of 19.3.2.1. Is that correct? > > JH > > > _______________________________________________ Sprinklerforum mailing > list [email protected] (mailto: > [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 > _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
