8.17.4.6.2 Retroactive Installation. When backflow prevention devices are to be retroactively installed on existing systems, a thorough hydraulic analysis, including revised hydraulic calculations, new fire flow data, and all necessary system modifications to accommodate the additional friction loss, shall be completed as a part of the installation.
I did not see a distinction for schedule systems, so it seems calcs are a given. Also, are you going back with QR heads since the occupancy is now LH? Reduced areas can help with the concerns of if it will work. Pay close attention to the interior as Thom stated. R/ Matt Matthew J. Willis, CET Automatic Fire Sprinklers Norred Fire Systems L.L.C. 318-387-1134 Voice 318-816-1087 Mobile 318-387-1163 Facsimile [email protected] > >-----Original Message----- > >From: [email protected] [mailto:sprinklerforum- > >[email protected]] On Behalf Of Thom > >Sent: Monday, September 27, 2010 12:44 PM > >To: [email protected] > >Subject: RE: tapping fire lead in for domestic > > > >This goes back to the basic purpose of backflow prevention. What are we > >protecting? We are protecting the Potable water supply from other things > >getting into it like, antifreeze, process water or anything which is not > >potable water. So this requires a RPZ to keep the antifreeze out of the > >potable water supply which extends up to the water meter for the new > >domestic service. If there is a fear that the domestic service could > >contaminate the potable water supply it will also be required to have a > >BFP > >device installed. (Think college labs or brewery's) This changes the > >incoming water supply significantly. Will it still meet the requirements > >for > >a Pipe Sch. System? Maybe? The typical pressure loss to a RPZ with two > >gate > >valves, 3" size anywhere from 8Psi to 13Psi depending upon flow. That > >could > >be a very big hit to a system with only 45Psi static or so. We'd like to > >think that the reduced flow for a LH instead of an OH occupancy would > >make > >that up, but there's only one way to know for sure. > > > >Subject: RE: tapping fire lead in for domestic > > > >If the domestic was tapped into the lead in before the alarm check and > >the appropriate backflow preventer was installed in the plumbing line > >why would this affect the sprinkler calcs? 13 does not require us to > >add in the domestic demand so I am a bit confused. > >Dewayne > > > > > >_______________________________________________ > >Sprinklerforum mailing list > >[email protected] > >http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > > >For Technical Assistance, send an email to: [email protected] > > > >To Unsubscribe, send an email to:[email protected] > >(Put the word unsubscribe in the subject field) > > > >No virus found in this incoming message. > >Checked by AVG - www.avg.com > >Version: 9.0.856 / Virus Database: 271.1.1/3153 - Release Date: 09/27/10 > >01:34:00 _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
