Of course it is important to have the ITC at the furthest remote location for a dry system, since you do want to know the longest time it takes to get water on the fire, but as Ron pointed out, in a wet system the volumetric flow rates are the same, no matter where (elevation being equal) in the system that ITC is located.
Dave David A. de Vries, P.E., CSP Firetech Engineering Incorporated 2715 Harrison St. Evanston, IL 60201 Tel: 847-733-0944 Fax: 847-866-6255 --- On Mon, 3/9/09, Timothy W Goins <[email protected]> wrote: From: Timothy W Goins <[email protected]> Subject: RE: Test/Drain at the Riser To: [email protected] Date: Monday, March 9, 2009, 10:34 AM I respectfully disagree. The purpose is to test the alarm device during a one head fire flow. Since we have to time the device, putting it at the most remote area makes more since, since we are simulating a fire at the most remote area and timing the activation of the alarm device. The alarm device must activate before 90 seconds (Electric) and or 5 minutes (Water Motor Alarm) you pick. If you are ONLY checking that the alarm device will work at the riser okay then, but I don't believe that that is the intent of the ITC. Just my opinion, Timothy Goins -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Mark Sornsin Sent: Monday, March 09, 2009 8:44 AM To: '[email protected]' Subject: RE: Test/Drain at the Riser Pardon me if this is ground that was already covered- I specify the Inspector's test Connection to be located at the sprinkler riser. This is NOT something that is new to NFPA-13 either. E.g., the 1996 edition (4-15.4.2) does not require the location to be at the riser - it doesn't specify any particular location. Commentary in the handbook that year specifically states that the purpose of the connection is to "verify the operation of the water flow alarm device(s)." The appendix dialogue recommends locating the connection at the remote location of the system - but this is by no means a requirement. Placing the ITC a the end of the system will not guarantee removal of all air from the system. We specify an air bleed valve be located at the high point(s) of the system for that purpose. I know there are automatic air releases that can be installed as well. The problems associated with air in the system are valid; that's why a means should be provided to remove the air. But excessive pressure from temperature rises is not one of those problems. In fact, it is precisely because of trapped air that that most tree systems don't have excessive pressure problems. The grids tend to have these issues because air can't be as readily trapped. That's why gridded systems should have a pressure relief. Of course, if you facilitate the removal of most air from a tree system, then a pressure relief is warranted on that system as well. Locating the ITC at the riser will help reduce the amount of new air into the system, as well as reduce the amount of freshly oxygenated water as a result of testing. This will reduce the potential for additional internal corrosion resulting from the oxygen in the system. (I seem to recall that this logic is used 'Down Under' as a means to extend the life of system piping) So, given that the purpose of the ITC on a wet system is to test the flow alarm, it makes more sense to have it at the riser where it is more convenient to facilitate the testing. Removal of air should be completed by air bleed valves or automatic air releases. Mark A. Sornsin, PE Fire Protection Engineer Ulteig Engineers, Inc. 3350 38th Avenue S. Fargo, ND 58104-7079 Direct: 701. 280.8591 Fax: 701.280.8739 Cell: 701.371.5759 [email protected] www.ulteig.com Confidentiality Notice This message may contain privileged and confidential information. If you think, for any reason, this message may have been addressed to you in error, you must not disseminate copy or take any action in reliance on it, and we would ask you to notify me immediately by return email to [email protected]. -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of George Medina Jr Sent: Sunday, March 08, 2009 10:28 PM To: [email protected] Subject: Re: Test/Drain at the Riser I?agree with you. George Medina Jr. Sr. Fire Sprinkler Designer 95-1015 Ka'apeha Pl. Mililani, HI 96819 808-388-5974 CL# -----Original Message----- From: Byron Blake <[email protected]> To: [email protected] Sent: Sat, 7 Mar 2009 6:29 am Subject: Test/Drain at the Riser Here here. We witness the very same problem on large wet gridded systems, just as your experience and research indicates.? ? We have one AHJ would REQUIRES test/drain ITCs. Guess where my false alarming issues are? I suspect this AHJ requirement is for their convenience and is not based on scientific laws of hydraulics and certainly not based on NFPA recommendations or typical trade practice. We have to live with the unintended consequences as a result of this "design compromise/requirement".? ? Byron? ? Byron Blake, CET? Service/Inspections? Freedom Fire Protection, LLC? Longmont, CO? ? -----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? ? _______________________________________________ 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) _______________________________________________ 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)
