It does not look like return bends are required based on every edition since 1985, including the 2007. It appears the standard assumes appropriate selection of piping materials and adequate water treatment over the life of the system to prevent this problem. Is there a return bend requirement that I've overlooked?
If there is no requirement, wouldn't this be important enough to generate a TIA for the 1999, 2002, and 2007 editions? Perhaps earlier editions as well if any older ones are still referenced by some local/state code. Bill Brooks Pittsburgh, PA -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of G. Tim Stone Sent: Thursday, May 03, 2007 9:27 AM To: [email protected] Subject: RE: So what's this return bend thing? There has been a lot of threads on this subject the past few days. After watching the video the big question that hits me is why weren't returns bends installed on the sprinkler drops to begin with? I have not heard anyone mention this yet. Had return bends been installed sediment would not be able build up at the Pendent Sprinkler Heads. I have been under the impression that this should be normal practice when installing Tri-Water Systems. G. Tim Stone G. Tim Stone Consulting, LLC NICET Level III Engineering Technician Fire Protection Sprinkler Design and Consulting Services 216 Huntington Acres - Richmond, VT. 05477 TEL: (802) 434-2968 Fax: (802) 434-4343 [EMAIL PROTECTED] > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:sprinklerforum- > [EMAIL PROTECTED] On Behalf Of Ron Greenman > Sent: Wednesday, May 02, 2007 4:27 PM > To: [email protected] > Subject: Re: So what's this return bend thing? > > I wondered how long it would be before this hit the list. About twenty > years ago I went to do a T.I. on a five story building in a suburb of > Seattle. IAt first I couldn't make heads or tails of the system. The > building engineer knew how to work it so while he was explaining it he > also was telling me its history. According to him this building system > (tri-water) was installed as a test bed before committing to 75 > stories of Columbia Tower. During the T.I. every head I pulled was > full of scale. I brought this to the engineer's attention so he could > inform the owner and joked about not going in the big black box. Since > then I've wondered when this would begin. Mike, comimg to the meeting > Tuesday? > > On 5/2/07, Steve Leyton <[EMAIL PROTECTED]> wrote: > > The point of interface is black pipe, so any pipe fitter will do. What > > happens downstream of the heat pumps is somebody else's business ... > > > > Steve Leyton > > PROTECTION DESIGN & CONSULTING > > > > > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] On Behalf Of Cliff > > Whitfield > > Sent: Wednesday, May 02, 2007 1:04 PM > > To: [email protected] > > Subject: RE: So what's this return bend thing? > > > > Do you have to be a sprinkler contractor to work on the HVAC or a duct > > man > > to work on the sprinklers in this building? > > > > Cliff > > Fire Design, Inc. > > > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] On Behalf Of Steve > > Leyton > > Sent: Wednesday, May 02, 2007 3:00 PM > > To: [email protected] > > Subject: RE: So what's this return bend thing? > > > > There were supposed to be filters at the cooling tower, and > > theoretically this design would be LESS subject to MIC and adulteration. > > But in a high-rise, we used one standpipe for supply and another for > > return, and since they were VERY large diameter I suppose anything's > > possible. Picture the cooling tower on the roof and the fire pump > > below - the standpipe sizes were "backward scheduled" because of > > velocity limits on the HVAC side. The buildings we did here had 8" at > > the top and 4" at the base ... > > > > The long-term problems with these systems, both high-rise and non, was > > leaks. Leaks at the valves, leaks here, there and everywhere, and the > > night-only work hours just added to the pain. > > > > > > Steve Leyton > > PROTECTION DESIGN & CONSULTING > > > > > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] On Behalf Of > > [EMAIL PROTECTED] > > Sent: Wednesday, May 02, 2007 12:50 PM > > To: [email protected] > > Subject: RE: So what's this return bend thing? > > > > Hmmmm, a "special one of a kind system", was this in the 1985 edition > > of NFPA 13? The oldest I've got at the office is '89, my '87 is at the > > house (that way the ME's here won't use it anymore, LOL) But this type > > system was in the '89. Often on these type of systems it may take years > > before this type of deterioration becomes evident. But the thing is, > > for circulating hvac systems we don't run hot or chilled water through > > black steel piping without some sort of chemical treatment. It sounds > > like the condition of this system is from lack of proper treatment and > > maintenance along with some installation/design errors. But the > > arm-overs are not the big issue since in a lot of if not most systems > > being served by a treated municipal water supply, you don't need to use > > arm-overs, might still be a good idea but arm-overs are generally > > reserved for raw water systems. Were there adequate flushing > > connections, were they used if present, who inspected the systems and to > > what level of detail is what I'd be asking. > > > > Craig L. Prahl, CET > > Fire Protection Group > > Mechanical Department > > CH2MHILL > > Lockwood Greene > > 1500 International Drive > > PO Box 491, Spartanburg, SC 29304-0491 > > Direct - 864.599.4102 > > Fax - 864.599.8439 > > [EMAIL PROTECTED] > > http://www.lg.com > > > > > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] On Behalf Of Michael > > M. Fitz > > Sent: Wednesday, May 02, 2007 3:28 PM > > To: [email protected] > > Subject: RE: So what's this return bend thing? > > > > I can't respond to the number of high-rise buildings that aren't > > sprinklered in Seattle........Rich? > > > > According to the information I was given, there were two buildings > > designed for a local developer that used a combined HVAC and sprinkler > > system. Unfortunately, pendant sprinklers were used in some locations > > along with the connections from the bottom of the pipe. Guess where the > > debris ends up? > > > > I was shown two heads, both of which were not plugged or obstructed in > > any way that had me concerned. I was led to believe that there were a > > substantial number of heads that were totally plugged and that is the > > reason for the major "maintenance". > > > > The "maintenance" procedures I have seen in photographs or was told > > about involved tapping the top of the pipe where there was access or > > from the side of the main or branch. > > > > As an engineer, I was impressed with the condition of the pipes as old > > as they were. I suspect this is because there was water treatment for > > the HVAC usage. > > > > Michael > > > > > > At 11:52 AM 5/2/2007, you wrote: > > >I would be interested to know how many high-rise buildings there are in > > > > >the town - that don't have sprinklers at all. Hmmmmmm? > > > > > >Terri Simmons Leyton > > >PROTECTION DESIGN & CONSULTING > > >Ph: 858-751-2930 > > >Fax: 858-751-2933 > > >Cell: 619-871-8450 > > > > > >-----Original Message----- > > >From: [EMAIL PROTECTED] > > >[mailto:[EMAIL PROTECTED] On Behalf Of Rod > > >DiBona > > >Sent: Wednesday, May 02, 2007 11:49 AM > > >To: [email protected] > > >Subject: RE: So what's this return bend thing? > > > > > >The craftsman was concerned with the integrity of the sprinkler system > > >because the buliding had been mentioned as a prime terrorist target. > > >That's interesting. > > > > > >-----Original Message----- > > >From: [EMAIL PROTECTED] > > >[mailto:[EMAIL PROTECTED] On Behalf Of Jamie > > >Seidl > > >Sent: Wednesday, May 02, 2007 12:11 PM > > >To: [email protected] > > >Subject: So what's this return bend thing? > > > > Michael M. Fitz, P.E., C.F.I. > > MDE Inc. > > 700 South Industrial Way > > Seattle, WA 98108 > > Main 206-622-2007 > > Direct 206-957-2140 > > Fax 206-622-2248 > > Home Office 360-427-2751 > > Cell 206-321-1804 > > www.mde.com > > _______________________________________________ > > 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) > > _______________________________________________ > > 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) > > _______________________________________________ > > Sprinklerforum mailing list > > [email protected] > > http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum > > > > To Unsubscribe, send an email to:Sprinklerforum- > [EMAIL PROTECTED] > > (Put the word unsubscribe in the subject field) > > > > > -- > Ron Greenman > at home.... > _______________________________________________ > 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) _______________________________________________ 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)
