There are times when folks just have to agree to disagree. I asked nicely last week to do just that and let this thread die. We all enjoy a good debate but not when it becomes unnecessary contentious Just because no one else agrees with your position is not a valid reason to say that they just don't give a damn. So let's play nice in the sandbox but pick another topic.
Roland AFSA sandbox referee On Mar 18, 2009, at 6:22 PM, Rodney Hamm wrote: > I find it VERY interesting that it has been over a week since I > suggested/challenged the forum participants to a simple experiment > and there > has been exactly ZERO responses to report any conclusions/findings. > > > > I am wondering if anyone actually tried the experiment referenced > below....if so, I wonder why has there been no response through the > forum? > Could it be that some have spent the 4-5 minutes and have decided > against > posting a response because the experiment does not support their > theory? > Could it possibly be that the various forum participants who believe > water > compression is the root cause of high system pressures are to "old > school" > and "close minded" (to use a phrase that was used to describe > me..heh heh > heh..really funny if you knew me at all) to consider a simple > experiment > that might in any way challenge their way of thinking? Or could it > possibly > be that water and air act differently to temperature changes in > Georgia than > any other place in the world? > > > > I am having a little too much fun with this email. > > > > On a more serious note, I was at another plant yesterday which has > the same > exact problem. This is really why I am writing this email. Warehouse > with 1 > gridded system and 7 tree fed systems. The problem only exists for the > gridded system; the remaining 7 systems had nominal pressure > differences > (0-10 psi difference) between the top & bottom gauges. On the gridded > system, the public pressure upstream of the alarm check valve was > fairly > steady all afternoon at ~60 psi. At 1:50 PM, the system pressure > downstream > of the alarm check valve was 190 psi. I described the problem to the > plant > engineer and he wanted me to explain the problem to the plant > manager. The > three of us returned to the riser at 2:10 PM and the system pressure > downstream of the alarm check valve was already up to 205 psi. We > have not > even entered our really hot days of summer yet! Riser nipples on the > near > main and the far main and the ITC for the system was attached to the > bottom > of the far main (in other words, the auxiliary or low point drain was > converted into an ITC by installing the base of a sprinkler head at > the end > of the pipe and then someone placed an ITC sign on the valve). This > system > was installed prior to the NFPA requirement of a 175 psi PRV for all > gridded > systems. I have recommended the provision of a 175 psi PRV, > installing air > bleed off valves and removing a significant amount of the trapped > air from > the system. The ITC piping "SHOULD" be arranged to flow water > through the > highest point of the system whenever possible, but some people just > don't > give a damn! > > > > > > Rodney K. Hamm, P.E. > President/Owner > Falcon Fire Protection > Office (478) 953-1677 > > Cell (478) 396-6988 > > > > Date: Wed, 11 Mar 2009 15:47:19 -0400 > > From: "Rodney Hamm" <[email protected]> > > Subject: RE: Test/Drain at the Riser > > To: <[email protected]> > > Message-ID: <[email protected]> > > Content-Type: text/plain; charset="us-ascii" > > > > I challenge you to try my suggested experiment! Even if you do not > want to > try it..try it with a preconceived notion that I am completely wrong. > > > > Take a completely 100% full glass of cold water (plastic would be > best) pull > some saran wrap over the top very tight and add a rubber band really > tight > to make sure no air leaks out. Make sure there are no air bubbles on > top. > Put the full glass of water in the microwave on HIGH for 2 minutes. No > pressure builds up inside the glass because water is not > compressible and > does not expand. Pressure will eventually build if you let the water > start > to boil. THEN do the same exact thing with a glass half full of cold > water. > Using saran wrap and a tight rubber band, you will see the pressure > increases dramatically and eventually will burst the saran wrap > after the > balloon effect! > > > > The results will be so obvious you will see my point. The plastic > film on > top allows you to see the dramatic difference in pressure increase > (100% > water vs. 50% air). My experiment is actually a closed system. I > will agree > that the volume is allowed to increase, but the only force which > allows the > plastic film to balloon is due to the increased pressure in the closed > container. If the same percentage of water/air was in a sprinkler > pipe, the > increased pressure caused by the temperature increase would cause > the system > pressure to increase dramatically due to the fact that there is no > change in > volume (until a leak or system rupture occurs). Of course, the best > test > environment would be to use a sprinkler system in an oven with a > calibrated > pressure gauge, but most of our forum readers would never take this > much > time and effort. The experiment I suggested is VERY convincing if > you are > willing to spend 5 minutes of your time to try. > > > > Air is compressible and water is not compressible. Temperature > increases or > decreases do not affect the pressure of a section of pipe filled > with 100% > water until the water begins to boil. Temperature increases will > cause the > pressure to increase if the same section of pipe is filled with air > or has a > significant percentage of air along with some water. Temperature > decreases > will cause the pressure to decrease if the same section of pipe is > filled > with air or has a significant percentage of air along with some water. > > _______________________________________________ > 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)
