We all now that there can not be two different pressures at the same point in a piping system at the same time. We also know that at some point one pressure will completely overcome the other pressure, and typically this is the FDC pressures overcoming the original primary supply pressure.
But... The FDC WILL, for some period of time, augment or assist. Depending upon the size of the piping system, until the total friction loss, either from the FDC connection back to the riser, or from the riser put to the FDC connection is overcome (including elevation pressure differences), and the pressure at either end exceeds the pressure provided by the water supply at that end, you will have times when BOTH supplies are acting upon the sprinkler system. In any event, the FDC is intended to be a secondary or augmenting supply for a fire sprinkler system and, if pressured up enough, becomes the primary supply, whether or not it is intended to be. As a side note, if the FDC is provided specifically for a standpipe or combination standpipe sytem in a "manual-wet" scenario, then it IS designed to provide the full flows and pressures of the standpipe system, keeping in mind the requirement to calculate the demand back to the FDC connection so the piping is sized to overcome the appropriate friction losses and elevations. Always be sure you coordinate the local fire department's ability to provide the required standpipe demands and/or keep the required pressures on the downside of 150 psi at the FDC. Ray Vance Chief Engineering Tech. Wayne Automatic Fires Sprinklers, Inc. www.waynefire.com -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Fletcher, Ron Sent: Friday, July 18, 2008 2:40 PM To: [email protected] Subject: RE: FDC Connection Item #2 is wrong it will not "augment or assist". The check valve in the FDC line will not open until there is a greater pressure on the inlet side than on the system side. Ron Fletcher -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Ray Vance Sent: Friday, July 18, 2008 11:30 AM To: [email protected] Subject: RE: FDC Connection After careful deliberation and reflection on all the previous posts to this thread, it seems to me we may be over-thinking the whole process. Since the FDC is "supplemental" to the water supply and is not intended nor required to provide a specifice flow, then the whole concept of where and how to tie it in becomes a much more simple process. (1) The FDC connection is a "Parallel" connection, and as such the water and pressure provided is really nothing more than a MANUAL secondary supply. (2) As a "Parallel" supply it will augment or assist the primary supply until which time as the PRESSURE from the secondary supply exceeds the primary. (3) Since it is a MANUAL supply, once the secondary exceeds the primary it in effect BECOMES the primary, unless manually throttled back to balance the primary supply pressure. No real difference than (2) fire pumps in parallel. (4) The FDC connection piping size only needs to be as large as the riser up to the point it connects to the system piping. If you calculate a system and need a 4" riser, but reduce the feed main to 3" from the top of the riser out to the system cross-main, then what does it matter if the 4" FDC connection piping connects to a 3" cross-main? The FDC connection piping, again, in effect, becomes a 4" riser (without the control valve) until it ties in to the sytem. (NO DIFFERENCE) (5) The new position of the NFPA technical committee to connect to cross-main or feed-mains only (no branch-lines)was made, in my opinion, to alleviate the inherent difficulties in overcoming extreme pressure losses due to both friction and velocity in smaller sized piping, (2" and smaller) when pumping higher flows at higher pressures, such as an FDC would provide from a pumper truck. (6) By limiting the connection to cross-main or feed-mains, the whole function of the FDC secondary supply overcoming and then BECOMING the primary supply is addressed, as you will not get the extreme pressure losses at higher flows, as you would in 2" or smaller branch-lines. (7) At any time the FDC supply pressure drops back below the original primary supply pressure, the whole process reverts back to the origianl primary supply. In my humble opinion, the NFPA standards relating to FDC connections, as written, already address MOST all the scenarios and issues discussed this fine Friday afternoon. With a little more thought process and understanding of the function of the FDC connection and its purpose, the whole point of "Where to tie it in", What size it needs to be", "Why tie-in only on feed or cross-mains", etc, becomes a much clearer picture. One final thought... Is is quitting time yet ;-) Ray Vance Chief Engineering Tech. Wayne Automatic Fires Sprinklers, Inc. www.waynefire.com -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Fletcher, Ron Sent: Friday, July 18, 2008 1:40 PM To: [email protected] Subject: RE: FDC Connection Flow and pressure cannot be supplemented (boosted) given the valve arrangement required by NFPA. The main riser check valve is either open or closed. The handbook calls it an "auxiliary water supply" to the system. Supplementing the automatic supply and increasing overall reliability. I have run into a lot of AHJ's that think the FDC will add to the flow and pressure from the city supply like a booster pump but it will not. The FDC becomes the sole source of water and pressure when used. Ron Fletcher Aero Automatic Sprinkler Phoenix, AZ -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Thom McMahon Sent: Friday, July 18, 2008 9:59 AM To: [email protected] Subject: RE: FDC Connection YES! SUPPLEMENTAL! As stated in NFPA 13, 2007 handbook A.6.8.1 You can do whatever you want thru those 2-2-1/2" connections, but somehow I don't think they were ever intended to "Supply" the entire demand for an ESFR 40' warehouse, or a .3/3000 design area, or a large deluge at a refinery, or--or---or--. If you do that dangerous thing (use Logic) we should only rely on 2-2-1/2" connections for up to 500 GPM. (See NFPA 14) Obviously you can, with the right pumper, and the right hydrant, flow more than 500 at an elevated pressure. But if it was the intent to "Supply" the entire system demand through the FDC, why are we not required to prove it? With a hyd. Calc. using the nearest hydrant and the smallest pumper or responding engine, and appropriate hose and friction loss? You really want to go down that path? Thom McMahon, SET Firetech, Inc. 2560 Copper Ridge Dr P.O. Box 882136 Steamboat Springs, CO 80488 Tel: 970-879-7952 Fax: 970-879-7926 -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Fletcher, Ron Sent: Friday, July 18, 2008 9:05 AM To: [email protected] Subject: RE: FDC Connection Supplemental? If 150 psi is pumped into the FDC the riser check will close making the FDC the only supply. Ron Fletcher Aero Automatic Phoenix, AZ -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Thom McMahon Sent: Friday, July 18, 2008 7:45 AM To: [email protected] Subject: RE: FDC Connection I think it's important to remember that the FDC is "supplemental" to the supply, not "Equal" to a supply. I feel that the 4" tied to the 2-1/2" MAIN meets the intent of the standard. It does not need to be 4" all the way from the riser to the FDC, when the FDC is remote from the riser and connects to a MAIN. Thom McMahon, SET Firetech, Inc. 2560 Copper Ridge Dr P.O. Box 882136 Steamboat Springs, CO 80488 Tel: 970-879-7952 Fax: 970-879-7926 -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Garth W. Warren Sent: Friday, July 18, 2008 9:38 AM To: [email protected] Subject: Re: FDC Connection it should be 4" from the connection to the main and then connected through a 21/2x21/2x4 tee. I disagree that NFPA allows for connection anywhere on the system, it states "provided the pipe size meets the requirements of 8.17.2.3." Otherwise "creative" companies would have 1" fdc piping connected to the end of a line. Garth ----- Original Message ----- From: "Brian Harris" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Friday, July 18, 2008 9:02 AM Subject: RE: FDC Connection > The FDC is actually remote from the riser & ties into a 2-1/2" floating > main. I think it should at least be 4" all the way to the back main and then > reduce it there.... > > > Brian Harris > FDFP INC. > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of > [EMAIL PROTECTED] > Sent: Friday, July 18, 2008 8:48 AM > To: [email protected] > Subject: Re: FDC Connection > > NFPA 13, 2007, section 8.17.2.3, (3) - For hydraulically calculated systems, > the fire department connection shall be permitted to be less than > 4 in. and no less than the size of the system riser, where serving one > system riser. > > My opinion is that the pipe from the FDC itself to the riser needs to be 4" > minimum. Based on your description I would interpret that as saying that > the 2 1/2" pipe on the FDC is not permitted as the riser is 4" and I am > assuming the 2 1/2" reduction is between the FDC and the riser. > > My opinion only. > > Andrew Weisfield > > > > > "Brian Harris" <[EMAIL PROTECTED]> Sent by: > [EMAIL PROTECTED] > 07/18/2008 08:36 AM > Please respond to > [email protected] > > > To > <[email protected]> > cc > > Subject > FDC Connection > > > > > > > Forum, > Quick FDC connection, I just saw on some drawings that came in that the > FDC > is 4" with a 4" check valve and then reduced down to 2-1/2" with a > reducing coupling. The system riser is 4", can you choke it down like > that? > Technically the FDC is the same size as the riser but where do you draw > the > line? I'm not liking it, what say you??? > > > Regards, > > > <http://www.firstdefensefire.com/> > > > > > > > > > E-mail message checked by Spyware Doctor (6.0.0.354) Database version: > 5.10290e http://www.pctools.com/en/spyware-doctor-antivirus/ > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum > > To Unsubscribe, send an email to:[EMAIL PROTECTED] > (Put the word unsubscribe in the subject field) > > > > This email is intended for named recipients only. > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum > > To Unsubscribe, send an email to:[EMAIL PROTECTED] > (Put the word unsubscribe in the subject field) > > > > > > E-mail message checked by Spyware Doctor (6.0.0.354) Database version: > 5.10290e http://www.pctools.com/en/spyware-doctor-antivirus/ > > > > > > E-mail message checked by Spyware Doctor (6.0.0.354) Database version: > 5.10290e http://www.pctools.com/en/spyware-doctor-antivirus/ > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum > > To Unsubscribe, send an email to:[EMAIL PROTECTED] > (Put the word unsubscribe in the subject field) > _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum 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 - http://www.avg.com Version: 8.0.138 / Virus Database: 270.5.1/1559 - Release Date: 7/17/2008 6:08 PM _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum 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 - http://www.avg.com Version: 8.0.138 / Virus Database: 270.5.1/1559 - Release Date: 7/17/2008 6:08 PM _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field) ----------------------------------------------------------------------- Wayne Automatic Fire Sprinklers, Inc. 2006 Inductee into 'The Players Hall of Fame' at The Great Games of Business http://www.greatgame.com Wayne Automatic Fire Spinklers, Inc. 'Best Places to Work' http://tinyurl.com/ov335 by Orlando Business Journal _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field) ----------------------------------------------------------------------- Wayne Automatic Fire Sprinklers, Inc. 2006 Inductee into 'The Players Hall of Fame' at The Great Games of Business http://www.greatgame.com Wayne Automatic Fire Spinklers, Inc. 'Best Places to Work' http://tinyurl.com/ov335 by Orlando Business Journal _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field)
