Interesting analysis Chris that I would agree with in general, however, I assume this is a dry system, right Steve?
If so, I would then assume that it is at least being partially trip tested annually, right? Of course it should be fully tripped tested every three years, but I am further assuming that is not happening, right? If it is being partially trip tested that is adding moisture to the system, and conceivably water because even a valve open only four turns lets water in and depending upon the circumstances 1) time before closing, 2) static pressure, 3) residual pressure, 4) pipe pitch, 5) system configuration, and so on, water can be going the wrong direction. The amount of water might be more than you think and D. Sornsin posted a few years ago about water that gets into dry systems during partial trip tests. So, lots of questions and several possibilities... Scott Futrell (763) 425-1001 x12 Office (612) 759-5556 Cell -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Cahill, Christopher Sent: Monday, December 02, 2013 6:44 PM To: [email protected] Subject: RE: Ice plug detection You say flawed air supply. I hear moisture getting into system from relatively moist air coming from the warm space and condensing and freezing at the -20 interface point. This isn't a low point problem from hydro testing or a place where you have a freeze thaw cycle which would allow water to move about. You can't get water (humidity, moisture) much past the interface point. The air coming from the compressor has a dew point, certainly much higher than -20. As soon as the air reaches the dew point is condenses out and if below 32 turns to ice. Once it's ice it's done moving. This all happens right around the interface. The pipe/air a few feet on the warm side is above 32 and it remains water. The only way to get ice remote from this point I think is to move it fast so it cools below its dew point farther along the path. Air ain't moving fast in a dry (PA, DIPA) system. And even then you'd get a gradient of ice not a pocket someplace else. I'd love to hear other thoughts on how it's possible to get ice remote where the moisture is from a compressor drawing in warm air. I don't think it's possible. I also defer to you looking at it. And seeing what I'm not. Your reality could be different than my idealized thoughts. Chris Cahill, PE* Senior Fire Protection Engineer Burns & McDonnell 8201 Norman Center Drive Bloomington, MN 55437 Phone: 952.656.3652 Fax: 952.229.2923 [email protected] www.burnsmcd.com Proud to be one of FORTUNE's 100 Best Companies to Work For *Registered in: MN -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Steve Leyton Sent: Monday, December 02, 2013 6:20 PM To: [email protected] Subject: RE: Ice plug detection Chris: We know exactly where the principal plugs are and why. I am programming a remediation and upgrade to address the cause, which is flawed air supply design and installation. The client raised the issue today of assessing the entire installation and assuring it's free of all plugs that may have formed downstream of where the recurring problem is located. Work area is very cold, frozen food storage, can't introduce stuff that will dirty the air, booger up the environment, etc. Anyone know for sure if ultrasound equipment will work in -20°F? Steve -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Cahill, Christopher Sent: Monday, December 02, 2013 3:20 PM To: [email protected] Subject: RE: Ice plug detection Why do you think you have plugs? Attic system or freezer? They usually form at the transition from warm to cold. Should be within a few feet of that on the cold side. And I'm sure per NFPA 13, pick your edition, been there a very long time. 7.9.2* Spaces Maintained at Temperatures Below 32°F (0°C). 7.9.2.1 General. 7.9.2.1.1 Where sprinkler pipe passes through a wall or floor into the refrigerated space, a section of pipe arranged for removal shall be provided immediately inside the space. 7.9.2.1.2 The removable length of pipe required in 7.9.2.1.1shall be a minimum of 30 in. (762 mm). Chris Cahill, PE* Senior Fire Protection Engineer Burns & McDonnell 8201 Norman Center Drive Bloomington, MN 55437 Phone: 952.656.3652 Fax: 952.229.2923 [email protected] www.burnsmcd.com Proud to be one of FORTUNE's 100 Best Companies to Work For *Registered in: MN -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Steve Leyton Sent: Monday, December 02, 2013 5:13 PM To: [email protected] Subject: Ice plug detection Okay, slow day, I'll go first. So ... who's got suggestions about how to find ice plugs in existing systems without pulling everything apart or running a borescope down the piping? Steve Leyton PROTECTION DESIGN & CONSULTING 2851 Camino del Rio South, Suite 400 San Diego, CA 92108 ------------------------------------------------------------- Ph: 858.751.2930 - ext. 102 Fax: 858.751.2933 Cell: 619.972.5696 _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
