I think you keep trying because you truly believe this is correct and that if only we could see what you are trying to say, we too would understand.
Your experiment only shows the expansion difference between air (cup 1/2 full) and water (cup completely full) since it is not a rigid pressure vessel (Like blowing up a balloon). The pressure induced by a miniscule amount of expansion of water within a closed pressure vessel is immense whereas trapped air greatly reduces the pressure level. Unfortunately it produces other issues (ie interfering with the alarm which as a side bar is really a consequence of the BFP cycling and corrosion). INstead of focusing on experiments and explanations, I prefer to comment on the original statement about the location of the ITV. Just like discussions on water velocity and hydraulic calculations, some very interesting and although heart felt, very wrong explanations have circulated through our industry. Locating the ITV at the end of the system has always been viewed as a marginal benefit (ie ensuring the system was actually together and purging air although it assure only a single path and purges a very limited portion of the system). The TC finally deleted the annex material and focused on what it was always intended to address and that is ringing of the bell. Being a long time member of NFPA 13, I can not say this is the official position of NFPA but can say that it is indeed what a very knowledgeable group of people explicitly decided to do. I suggest we agree to disagree and let this thread die. That is not an unacceptable or unusual final position within such a large group. Roland On Mar 11, 2009, at 12:47 PM, Rodney Hamm wrote: > Chris (& everyone else on the forum), > > > > 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. > > > > 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. > > > > By the way, I have conducted this experiment in the real world with > steel > pipe and significant temperature changes. I live in the great state of > Georgia and I have personally witnessed the pressure increase > dramatically > with the control valve on the system completely closed (i.e. no > possible way > any water entered the system!). I have also confirmed the system > pressure > decrease as the temperature decreases in the same situation with no > evidence > of any water discharging from the system. I will go to the grave > knowing I > am completely correct regarding this matter (and I am really an open > minded > person; I am not pig headed and/or unwilling to consider a different > point > of view). I actually make a concerted effort to learn from other > people's > experiences and try to keep an open mind whenever possible. I am > truly > almost to the point of giving up regarding this subject. I really do > have a > lot of other responsibilities, but for some unknown reason, I feel > compelled > to continue responding to the various posts. I think I might just > need some > professional help! > > > > Take care & let us all know how the experiment goes, > > > > Rodney K. Hamm, P.E. > President/Owner > Falcon Fire Protection > Office (478) 953-1677 _______________________________________________ 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)
