NFPA 13: 6.9.4.1 Electrically operated alarm attachments forming part of an auxiliary, central station, local protective, proprietary, or remote station signaling system shall be installed in accordance with NFPA 72R, National Fire Alarm CodeR.
NFPA 72: 5.10 Sprinkler Waterflow Alarm-Initiating Devices. 5.10.1* The provisions of Section 5.10 shall apply to devices that initiate an alarm indicating a flow of water in a sprinkler system. 5.10.2* Initiation of the alarm signal shall occur within 90 seconds of waterflow at the alarm-initiating device when flow occurs that is equal to or greater than that from a single sprinkler of the smallest orifice size installed in the system. A.5.10.2 The waterflow device should be field adjusted so that an alarm is initiated no more than 90 seconds after a sustained flow of at least 40 L/min (10 gpm). Features that should be investigated to minimize alarm response time include the following: (1) Elimination of trapped air in the sprinkler system piping (2) Use of an excess pressure pump (3) Use of pressure drop alarm-initiating devices (4) A combination thereof I have attached the applicable requirements above for reference (NFPA 2002 Edition). For electronic fire alarms, the alarm device should activate within a maximum of 90 seconds after water flow of 10 gpm or more occurs at the alarm initiating device. For wet systems, the industry standard is to ensure electronic water flow alarms within 90 seconds of a fully open Inspector's Test Connection. This is really not difficult to accomplish as long as the system does not have large pockets of trapped air. Remove the air, as outlined in Section A.5.10.2(1), and set the delay for 45-60 seconds; alarm activates <90 seconds and there are no false alarms. Chris used his example to show how much smarter he is than the "FM Guy", but he failed to mention that he had no idea why the system required 58 seconds for the electronic water flow switch to activate. If a wet system is full (or close to full of water), the water flow switch activates almost immediately when the Inspector's Test Connection is opened. Sprinkler system people with several years of experience in the field know this to be true regardless of the size of the system. If a wet system has significant pockets of trapped air, the decompression of the air pockets results in a significant delay prior to the initial activation of the flow switch. The pockets of trapped air will typically result in a cycling waterflow switch and other serious issues as well. If the flow switch in Chris's example cycled too quickly, his 45 second delay probably created a code violation (I have seen several waterflow switches cycle for 10-15 minutes without ever activating the alarm => remove air pockets and the problem is resolved). I realize this is a rather harsh comment, but I personally think Chris and the "FM Guy" did not help the customer very much. I wonder if the system still has trapped air pockets and all of the issues/problems which are caused by large pockets of air in wet sprinkler systems? Oh yeah, I almost forgot, someone stated that the alarm issues are strictly for the alarm company employees....maybe it should be their responsibility to remove the air pockets! I do not know where to begin with the 6.5 minute requirement referenced by Chris. This is very misleading and I would strongly suggest against applying this logic in the real world. NFPA 13 allows up to 5 minutes for the local waterflow alarms to activate; however, this does not apply to the electronic alarm devices. NFPA 13 indicates all electronic waterflow alarm devices shall comply with the applicable portions of NFPA 72. The 5 minute requirement allows multiple retard chambers and other delays to prevent nuisance water motor gong alarms. The NFPA 13 & NFPA 72 requirements are based on wet systems which are full or close to full of water; therefore, it is simply illogical to accept the premise that waterflow would occur at the sprinkler riser 1-5 minutes after the Inspector's Test Connection was opened. Imagine a 10 in. diameter section of pipe 2 miles long with 90 degree elbows on each end facing upward. If the section of pipe was 100% full of water and you poured a 5 gallon pail of water in one end, the water would overflow immediately at the far end! Same thing only we are dealing with a smaller volume. I have resolved this exact waterflow switch alarm problem more times than I care to remember; it is so common that I think I am in the early stages of a Crusade to inform our industry. I have also obtained indisputable facts regarding the excess pressure development in sprinkler systems due to trapped air pockets. I have identified and resolved the excessive pressure problem (due to air in the system) 17 times this year alone! Most of these systems had >300 psi in the afternoon and 60-150 psi (depending on the static water supply) during the morning hours. Remove the trapped air and the pressure fluctuations are gone. Give me a call if anyone is truly interested and I will send you the data from my electronic data logger (I log the wet sprinkler system pressure; every 30 seconds for 7 days). We can all learn from each others experiences as long as we all maintain an open minded approach. I hope this information is beneficial to someone out there! Rodney K. Hamm, P.E. President/Owner Falcon Fire Protection Office (478) 953-1677 Cell (478) 396-6988 From: "Chris Cahill" <[email protected]> Subject: RE: water flow timing To: <[email protected]> Message-ID: <91f4ffce394b4f71bea941947a42a...@chris2005> Content-Type: text/plain; charset="us-ascii" LOL, 1-Doesn't mean I'm not here. 2-Doesn't mean I'm wrong. 3-My scope of work is 13, sounds like the FA guy's problem. Seriously though it has only come up once that I have been part of in the private sector. After a long discussion on site the FM made us set the retard on the flow switch so that the alarms rang in 60 seconds. We could see the meter spin with surges in the street and our pressure climb 20 psi in a couple minutes. It was a very large system (3" bl and 6" and 8" mains) and took 58 seconds for the flow switch to even move. 1/2" head ITV because of the office parts. He was happy when we passed at 60 sec. with no retard. I advised him he created a situation that would result in false alarms. Of course he knew more than me. 5-10 minutes later BS'ing in the parking lot sure enough the FD was dispatched for a flow alarm. He was on the VFD and his pager went off for the building he was at. Priceless and yes I did point out the "I told you so" as I left it in his "capable" hands, he was a @#$^$%&$...@#. I win after 3 more false alarms over the weekend and they set the retard back to 45 seconds. 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 Thomas Watt Sent: Wednesday, July 15, 2009 11:12 AM To: [email protected] Subject: Re: water flow timing Chris, you would be butting heads with every AHJ in the Central Florida area. I have never gotten a CO without sounding alarms within 60-90 secs. Thomas Watt ----- Original Message ----- From: "Chris Cahill" <[email protected]> To: <[email protected]> Sent: Wednesday, July 15, 2009 11:53 AM Subject: RE: water flow timing > Right or wrong I always reconciled 13 vs. 72 like this. The flow switch > must activate within the parameters of 13. 5 minutes. Once the paddle > moves and the electrical connection is made 72 takes over and the FA must > respond within the parameters of 72. 90 seconds. So in theory 6.5 > minutes > could pass between opening the inspectors test valve and the alarm signal > engaging in the FAP. > > Chris Cahill, P.E. > Fire Protection Engineer > Sentry Fire Protection, Inc. Date: Wed, 15 Jul 2009 10:53:59 -0500 From: "Chris Cahill" <[email protected]> Subject: RE: water flow timing To: <[email protected]> Message-ID: <8d141ac0c9c645fab97b4aeb7ff6a...@chris2005> Content-Type: text/plain; charset="us-ascii" Right or wrong I always reconciled 13 vs. 72 like this. The flow switch must activate within the parameters of 13. 5 minutes. Once the paddle moves and the electrical connection is made 72 takes over and the FA must respond within the parameters of 72. 90 seconds. So in theory 6.5 minutes could pass between opening the inspectors test valve and the alarm signal engaging in the FAP. 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 Jim Johnston Sent: Wednesday, July 15, 2009 10:14 AM To: [email protected] Subject: RE: water flow timing NFPA 72 5.11.2 says within 90 seconds. Jim Johnston, P.E. Fire Protection Engineer Inland Fire Protection, Inc 1100 Ahtanum Road Yakima, WA 98903 Phone 509-248-4471 Fax 509-248-1180 [email protected] -----Original Message----- From: Geoff Dyce [mailto:[email protected]] Sent: Wednesday, July 15, 2009 7:55 AM To: [email protected] Subject: water flow timing We are having a discussion regarding time required for water flow notification. One party says on a wet system, there is no particular time requirement. Another party says there is a time limitation. What say you all??? Thanks in advance. Geoffrey H. Dyce Operations Manager/NICET IV DELTA Fire Sprinklers, Inc. A Vetran Owned Small Business Ph: 407-328-3000 ext 143 Fx: 407-575-9991 E-Mail: [email protected] _______________________________________________ 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)
