Rodney: Just curious. I'm guessing there's gotta be a few dry systems down there in unheated warehouses with extreme temp swings. So in these systems with 100% air, do you find the pressure above the dry valves climbing to extreme levels in the summer?
Dave Sornsin General Manager - Fargo Office Nardini Fire Equipment 303 20th St N Fargo, ND 58102 701.235.4224 fax 701.235.5089 cell 701.371.0643 [email protected] www.nardinifire.com www.minidamswilldestroyusall.com -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Rodney Hamm Sent: Wednesday, March 18, 2009 8:23 PM To: [email protected] Subject: Excessive system pressure 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 _______________________________________________ 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)
