We used to use this super pressure method a lot here also but it seems to have fallen out of favor.
On Sun, Mar 1, 2009 at 3:08 PM, Chris Mak <[email protected]> wrote: > You are right George. > > We seem to have very lille problem here in NZ with internal corrosion. > Oibviously, some does happen, but not on a frequent basis. > > We believe one of the reasons is that we do not a requirement for inspectors > test connections at all, and thus minimise the introduction iof oxygenated > water into our systems. > > Most of our systems are based on super-pressurising the system, with the > alarm signal generated by a drop in pressure. We need air trapped in the > system, to ensure that the pressure gauges don't operate like a temperature > gauge. The trapped oxygen seems to combine with the iron very quickly to form > the black iron oxide- can't remember my chemistry I ferrous or ferric oxide. > > I have seen pipe removed after 50 years of service which is as good as new. > With leaky systems, where fresh water is being introduced, I have seen pin > hole corrosion develop, under the typical turbacles, at the air water > interface. > > Regards > > > Chris Mak > Aon Sprinkler Certification > Via Blackberry > > > ----- Original Message ----- > From: "George Church" [[email protected]] > Sent: 01/03/2009 05:58 PM EST > To: <[email protected]> > Subject: RE: statistics > > > > Well, if you want to meet someone with influence and pull with the > development of NFPA #13, simply grab a copy of it and turn to the last page, > and look in the mirror. You'll find a FORM FOR PROPOSALS ON NFPA TECHNICAL > COMMITTEE DOCUMENTS that enables you to influence the development of NFPA > #13. > > You may wish to introduce the requirement for air bleed-offs at high points, > because otherwise you'll need to introduce a requirement for ITCs to be > piped off the highest point and in many cases, that's the ridge far away > from the exterior wall you'll want it piped to. I think separating the two > items- air blled-off and ITC- will also enable you to not be stopped by > those who like the ITC at the riser for convenience, economy, because their > riser manifold design has it there, whatever. While you may use it as an air > bleed-off, the ITC's function IS to test the alarm device. Hence the > suggestion to enable two items to address two different tasks. > > I'm not a metallurgist, nor would many watch one on TV, so I won't address > the claims you've made. I believe there was discussion many moons ago on the > Forum WRT the NZ lack of MIC versus USA experience, and the difference in > ITC Location was offered up as a possible reason. > > I understand PRVs will be required on all wet systems shortly, so one of the > problems is already being addressed; if those were gridded systems, as I'd > expect in a >1M SF facility, then the code already addressed the problem of > high pressure and you applied it- PRVs. > > Rather than list all reasons in one proposal, I'd suggest breaking it into > twain and providing technical substantiation for each. > > Congrats on going public with your complaints about ITCs, and I encourage > you to take the next step so your thoughts will be considered by the > committee. > glc > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Rodney Hamm > Sent: Sunday, March 01, 2009 5:38 PM > To: [email protected] > Subject: RE: statistics > > If anyone has any pull or influence with the development of NFPA 13........ > > Please discuss the idiotic approach of installing Inspector's Test > Connections at the sprinkler riser (~12 in. downstream of the flow switch). > This has been considered "acceptable" by NFPA 13 since 2002 and is quickly > becoming standard practice in the great state of Georgia. There are several > significant reasons why this is a bad idea AND from an engineering > standpoint this is a very poor design. The inevitable trapped air in the > system causes or can potentially cause a number of problems: Excessive > system pressure when temperatures increase, false water flow alarms due to > air pocket expansion/contraction, failed water flow alarms due to cycling > flow switches, increased rust on the interior surfaces of sprinkler piping, > etc. > > >From what I have seen, most contractors or sprinkler designers who > primarily > install or design new systems have no idea this approach causes problems for > the building owner and/or fire protection system inspectors. I can confirm > these are common problems at several of the facilities I have visited over > the past few years. In many instances, the only effective solution is to > install a suitably located Inspector's Test Connection or bleed the air > pockets using sprinklers at the highest elevations. We have installed air > bleed off connections for numerous systems simply to allow trapped air to be > removed from the high point. The problem is access at some facilities after > the solid ceilings or other obstructions have been introduced. > > In my humble opinion, Inspector's Test Connections should be installed at > the most remote point of each system. The connection point (prior to being > piped to within 6 ft. of the floor level) should be at the highest elevation > of the sprinkler system piping whenever possible. Auxiliary drains or low > point drains should NOT be considered Inspector's Test Connections. > > I would assume it is safe to say anyone who has enough experience and > personal dealings with inspections and/or problem solving (after the design > phase and initial installation project has been completed) realizes that the > Inspector's Test Connection serves more purposes than just testing the water > flow alarms. {I have heard "the sole purpose of the ITC is to test the alarm > device" so many times that I get a smile every time someone spouts it.} I > simply disagree with the relatively recent change in NFPA 13 which allows > this approach. I strongly believe the practice of installing the Inspector's > Test Connection a few feet downstream of the water flow switch should be > considered unacceptable. > > In many instances, the fire alarm companies and building owners have to deal > with the issues caused by this poor design. They rarely if ever realize the > true source or reason for the intermittent false alarms. They simple bypass > the alarm or set the delays so high that flow switch cycling becomes a > problem during alarm testing. > > We see systems with >175 psi on a regular basis caused by this > problem.......some systems even peg the 300 psi gauges. On of my customers > had 5 separate incidents where sprinklers developed leaks and/or popped open > due to excess system pressure during Spring & early Summer of 2007. We added > pressure relief valves in August of 2007 for all of their wet systems and > this resolved the problem. This is a >1 million sq. ft. facility with > several wet systems. False fire alarms and excess air pressure are very > common problems when the ITC is not located at the most remote and/or > highest elevation of the system piping. I could provide many more examples, > but I think I have made my point. > > Black steel, moisture and trapped air allows more rust to develop on the > interior surfaces of the sprinkler piping than if the majority of the > sprinkler piping is full of water. Therefore, it would be safe to conclude > that trapped air in the sprinkler systems will shorten the life of the > sprinkler system piping. > > The fact that someone or some group convinced the NFPA committee to change > the standard and the fact that the approach saves time and money during > installation does not make it a good engineering design! > > There are probably a few instances where placing the ITC a few feet > downstream of the flow switch should be considered acceptable due to limited > or no feasible alternatives; however, these instances should be the last > resort alternative rather than standard practice. > > Just one man's perspective!! I wonder if anyone on this forum agrees with me > on this subject. > > Rodney K. Hamm, P.E. > President/Owner > Falcon Fire Protection > Office (478) 953-1677 > Cell (478) 396-6988 > ------------------------------ > > Date: Sun, 1 Mar 2009 11:53:24 -0500 > From: Mike Cabral <[email protected]> > Subject: RE: statistics > To: [email protected] > Message-ID: <20090301115324.sekkv.1683217.r...@mp20> > Content-Type: text/plain; charset=utf-8 > > A long time ago when I was a young man I did a lot of work on old systems in > industrial buildings in New England. . . old textile mills mostly. I wish I > had a few $ for every piece of 3/4" pipe I changed to 1" on these old pipe > schedule systems. > > A high vent was almost always present with instructions on filling the > system posted on the riser. The location of the vent or vents was stated and > the order or the procedure for operating them was often posted. Some times > the instructions would advise you to open the vent while filling other times > the vent was opened after the system was under pressure. > > If you followed the instructions you went home for the day and that was > that. If you didn't you could expect a call sometime through the night > because water would move as the air migrated through the system and trip the > alarm. > > These systems were old in the late 1960's and early 1970's. . . willing to > bet most of them are still in service. Venting the air keeps trapped air out > of the mains and cross mains which would eliminate the air water interface > which if present invites corrosion. > > Sometimes there is something to learn from accent history > > Mike Cabral > > ---- George Church <[email protected]> wrote: >> Minimize false trips and air for MIC. >> >> -----Original Message----- >> From: [email protected] >> [mailto:[email protected]] On Behalf Of Forest > Wilson >> Sent: Sunday, March 01, 2009 10:43 AM >> To: [email protected] >> Subject: Re: statistics >> >> What advantage is there to venting the air? Other than response time? >> Sent from my Verizon Wireless BlackBerry >> >> -----Original Message----- >> From: "George Church" <[email protected]> >> >> Date: Sun, 1 Mar 2009 10:12:12 >> To: <[email protected]> >> Subject: RE: statistics >> >> >> Nothing fancy, a 1" ball valve; or an ITC-type set up if you want to get >> fancy and run it out, we don't always. >> >> Potter has an auto air release you could also use. >> >> -----Original Message----- >> From: [email protected] >> [mailto:[email protected]] On Behalf Of Ergo >> Sent: Sunday, March 01, 2009 10:02 AM >> To: [email protected] >> Subject: Re: statistics >> >> George, >> >> You have a way to bleed the air off of the system at the high point? This >> sounds like a good idea. Cold you explain some more on how to make this >> happen? >> >> Thanks, >> >> >> Ergo >> >> >> >> On Fri, Feb 27, 2009 at 8:38 AM, George Church <[email protected]> wrote: >> >>> Venus and Mars. I raise hypothetical questions, you hunter-gatherers >> answer >>> the question instead of pursuing the issue of statistics :) and how to >> find >>> them. Quite a change from the suggester of a group hug:) >>> >>> I agree on the BFP, MIC, and although we often have the ITC on a riser >>> manifold, we generally have a way to bleed the air off the high point to >>> avoid false signals. >>> >>> Good point on calculating the Expected Value, taking the frequency a step >>> further and including impact. >>> >>> glc >>> >>> -----Original Message----- >>> From: [email protected] >>> [mailto:[email protected]] On Behalf Of Chris >>> Cahill >>> Sent: Friday, February 27, 2009 11:02 AM >>> To: [email protected] >>> Subject: RE: statistics >>> >>> But if you are doing a risk analysis you are forgetting the outcome side. >>> For example, failure of a BFP to protect the public in theory could be >>> catastrophic to many if not all on the water supply. Failure of a BFP in >> a >>> fire should only affect one building. On the theoretical side some may > die >>> from the fire and/or billions of $ lost but it ain't getting a whole city >>> sick or contaminating an aquifer used by 10's of millions. So the rates >>> alone are irrelevant. You need to take risk and multiply it by loss then >>> you have the answer on which way to go. Don't get me wrong BFP's are a >>> bunch of hooey. >>> >>> 1st question - about 0 for both, BFP's are a waste of money in the first >>> place. >>> >>> 2nd - MIC is an issue we need to or will be dealing with more often. >>> Remember ESF only seems at this point to be an Allied problem. I vote >> treat >>> the MIC. >>> >>> 3rd - off the end gets some/most air out reducing false alarms and >>> eliminating some air/water interface rusting. MIC coatings help with the >>> added oxygen in the water. I vote end. >>> >>> Chris Cahill, P.E. >>> Fire Protection Engineer >>> Sentry Fire Protection, Inc. >>> >>> 763-658-4483 >>> 763-658-4921 fax >>> >>> Email: [email protected] >>> >>> Mail: P.O. Box 69 >>> Waverly, MN 55390 >>> >>> Location: 4439 Hwy 12 SW >>> Waverly, MN 55390 >>> >>> -----Original Message----- >>> From: [email protected] >>> [mailto:[email protected]] On Behalf Of George >>> Church >>> Sent: Friday, February 27, 2009 9:15 AM >>> To: [email protected] >>> Subject: statistics >>> >>> Just as we recently discussed that we don't know how many heads a year > are >>> installed, or how many have been installed in the past 100+ years, when >>> discussing unexpected activations, statistics of some order of magnitude >>> would be helpful in numerous other things. >>> >>> Which occurs more frequently, failure of a backflow to protect the public >>> supply, or failure of a backflow to allow full forward flow of water to a >>> sprinkler system when needed? >>> >>> Is the possibility of MIC greater than the likelihood of ESF from MIC >>> coatings? This would aid us in deciding, on systems comprised of combo >>> steel >>> and CPVC, if we want to use uncoated pipe (more susceptible to MIC) or >> risk >>> Environmental Stress Fractures? >>> >>> Is it better to run the ITC off the riser and limit the new oxygen into >> the >>> system, or run it off the tail end and check for blockage? >>> >>> There are countless other items we have no data upon which to base our >>> decisions. Our best guesses may be completely wrong- guess our batting >>> average would be no better than 50-50, and likely the answer may be based >>> on >>> something more important but not considered. >>> >>> glc >>> >>> -----Original Message----- >>> From: George Church [mailto:[email protected]] >>> Sent: Friday, February 27, 2009 10:07 AM >>> To: '[email protected]' >>> Subject: RE: Fire marshall >>> >>> Just as a plumber would assume testing a sprinkler backflow is limited to >>> the backflow portion of the test, not aware of the forward flush we're >> more >>> concerned about. >>> >>> glc >>> > > > > _______________________________________________ > Sprinklerforum mailing list > http://lists.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) > > _______________________________________________ > Sprinklerforum mailing list > http://lists.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) > > > This document should only be read by those persons to whom it is addressed > and is not intended to be relied upon by any person without subsequent > written confirmation of its contents. 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