The figures that are shown for this section [A.8.17.5.2.2(a) and (b)] show your classic combination standpipe, though. That's what is confusing me. I've always thought of "inside hose" or "hose connections supplied by a sprinkler system" as being differentiated from standpipe connections because they are DOWNSTREAM of the system control valve (is that correct?). It seems like the handbook is saying you need to add a hose allowance (like 50 or 100 GPM) at the hose valve connection for this scenario (classic combo standpipe shown in figure) as well as for small "inside" hose connections.
What am I missing? -Kyle M From: Sprinklerforum [mailto:[email protected]] On Behalf Of Steve Leyton Sent: Thursday, August 31, 2017 9:22 AM To: [email protected] Subject: [EXTERNAL] Re: NFPA 13 8.17.5.2.2(1) Yes, for hose connections that are supplied by a sprinkler system. Adding the flow at the available pressure makes get an allowance as opposed to having to balance the flows and pressures the way you would for added rack demand. However, hose connections supplied by a sprinkler system are most assuredly not standpipes. My opinion only ... Steve -------- Original message -------- From: "Kyle.Montgomery" <[email protected]<mailto:[email protected]>> Date: 8/31/17 8:21 AM (GMT-08:00) To: [email protected]<mailto:[email protected]> Subject: RE: NFPA 13 8.17.5.2.2(1) I read the handbook commentary for 8.17.5.2, and now I'm confused again: "When either one of the hose connections described in 8.17.5 is provided, the flow rates need only be added to the sprinkler system at the design pressure available at the point of connection to the sprinkler system pipe." Is this not referring to a hose stream allowance? Also, can anyone comment on Colin's original question? (Sorry for hi-jacking your thread) -Kyle M From: Sprinklerforum [mailto:[email protected]] On Behalf Of Kyle.Montgomery Sent: Wednesday, August 30, 2017 4:19 PM To: [email protected]<mailto:[email protected]> Subject: [EXTERNAL] RE: NFPA 13 8.17.5.2.2(1) This has been my understanding as well. I wonder why more people don't do it this way? I've done it myself one time. But usually am met with a lot of skepticism in the form of "well, if this is acceptable, why doesn't everyone do it that way?" From: Sprinklerforum [mailto:[email protected]] On Behalf Of Steve Leyton Sent: Wednesday, August 30, 2017 4:01 PM To: [email protected]<mailto:[email protected]> Subject: [EXTERNAL] RE: NFPA 13 8.17.5.2.2(1) Right. Basically, if you're flowing an attack stream from the SP, you don't need the sprinklers. If the sprinklers are working, you don't need attack stream from the SP. Inside hose allowance is for hose connections to sprinkler systems, which by definition are not standpipes. Where you need to add the HSA is if you have a common water supply to hydrants and the system in question, i.e. outside hose. This is all pretty well spelled out in NFPA 13, 2016 ed., §11.1.6.3.1 and §11.1.6.4. SML From: Sprinklerforum [mailto:[email protected]] On Behalf Of [email protected]<mailto:[email protected]> Sent: Wednesday, August 30, 2017 3:54 PM To: [email protected]<mailto:[email protected]> Subject: RE: NFPA 13 8.17.5.2.2(1) Aren't they treated as separate calculations. Just as site fire flow is not added to the fire sprinkler system. That is how I was taught. Actually, I think it was Steve L that beat that into my head long ago. From: Sprinklerforum [mailto:[email protected]] On Behalf Of Steve Leyton Sent: Wednesday, August 30, 2017 3:52 PM To: [email protected]<mailto:[email protected]> Subject: RE: NFPA 13 8.17.5.2.2(1) Roland? Ray Lambert are you out there? This is a LONG-simmering topic of discussion the AFSA tech dept. and also the NFPA community. Short answer is NO, you do not have to include any HSA for standpipe connections. My opinion only (after Roland branded it on my a**). Steve L. From: Sprinklerforum [mailto:[email protected]] On Behalf Of Kyle.Montgomery Sent: Wednesday, August 30, 2017 3:36 PM To: [email protected]<mailto:[email protected]> Subject: RE: NFPA 13 8.17.5.2.2(1) I'm wondering why it isn't more common, considering you purchase about half as many PRVs that way. Would you need to flow a hose allowance through that valve as part of you sprinkler calculation? From: Sprinklerforum [mailto:[email protected]] On Behalf Of Steve Leyton Sent: Wednesday, August 30, 2017 3:21 PM To: [email protected]<mailto:[email protected]> Subject: [EXTERNAL] RE: NFPA 13 8.17.5.2.2(1) It's not the most common arrangement but a common pressure reducing valve on the supply side of the floor control and hose connection for a combined standpipe is acceptable so long as it all works hydraulically. The foregoing is my opinion only and is not intended to represent the NFPA 14 Technical Committee, nor serve as an interpretation of the standard. Steve Leyton Protection Design & Consulting San Diego, CA From: Sprinklerforum [mailto:[email protected]] On Behalf Of Kyle.Montgomery Sent: Wednesday, August 30, 2017 3:19 PM To: [email protected]<mailto:[email protected]> Subject: RE: NFPA 13 8.17.5.2.2(1) Not to sidetrack this thread... but is the arrangement Colin is describing acceptable? I have never found anything in the code saying it isn't, but I would say that almost every installation I've seen has a separate pressure-reducing hose valve and pressure-reducing system control valve... which is obviously more expensive. From: Sprinklerforum [mailto:[email protected]] On Behalf Of Colin Carew (Cambridge) Sent: Wednesday, August 30, 2017 2:10 PM To: [email protected]<mailto:[email protected]> Subject: [EXTERNAL] NFPA 13 8.17.5.2.2(1) Wondering , what is reason behind the Control valve and check valve of the same size at the connection is required per 13 8.17.5.2.2 (1) I have a connection , where I connect to the standpipe with 2.5" pipe and then to a PRV control valve , then after I feed a standard hose valve and reduce down to 2" for my sprinkler control valve assembly . Thanks . Colin Carew
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