Brad, you are suggesting there is a problem with density. There may be room for improvement but first I think a real problem needs identification. "too high for low ceilings and too low for high ceilings"...Why would you say that? I realize the 20' step seems odd but that doesn't translate to too high/low? Not sure there can ever be too much (within reason). Do you have evidence systems with the current 'correct' density are failing at high ceilings? If not then it can't be low. Really by far the biggest failure problem is close valves. Develop a valve that can't be closed when there is a fire and you are on to something.
Is anyone aware of a 'correct' density that failed to control the fire. There has to be some but not many I suspect. I'm talking it was designed and installed fully correctly and still failed. Of course there is a whole other debate on what is a failure. Closed valve, pumps off, gopher homes in the UG is not related to a density that is too high or low. HPS plastics with OHII would NOT be a 'correct' density as an example, an office that fails with 0.1 and all the plastics in the furniture and computers would arguably be a 'correct' density. Even if you succeeded in make a change for a linear density vs. height why do you think linear is correct? Seems that would be too simple accounting for delays in activation due to height alone. Same fuel under a taller ceiling I'd think would need more than the same increase in density as height to get the same performance. All this though is beating around the same current evolution that has been going on for about 130+- years. The first revolution was run from the fire, then some caveman revolutionized fire suppression by peeing on the fire. A bucket was probably the next. Fire hose was probably the next, although might be argued just an evolution of the bucket. What's the sign in Backdraft 230 years unimpeded by progress? And the last revolution was some get the wet stuff on the red stuff automatically. Arguably the stick of dynamite under the water tank was not much more than we do today with fire sprinklers. We're just a little more elegant or so we believe. If you want to make a mark come up with the next revolution. Force fields, better water (and I don't mean foam or .x% additives to what is still basically water), robots (your VESDA system causes a fleet of cheap robots to spring into action), nanobot firefighters in everything made? Not sure tweaking the density on something that works very well and is considered cheap is going to get far. Remember when there was a place holder in NFPA 13 for ESFR type systems for ordinary type occupancies, like your office? Looks like that's gone due to not enough of a change to pursue as another example of an idea that went nowhere. Chris Cahill, PE* Senior Fire Protection Engineer, Aviation & Facilities Group 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 Brad Casterline Sent: Monday, June 04, 2012 3:32 PM To: [email protected] Subject: RE: 7psi Minimums for Fire Sprinklers :) Thanks George, I'll try to clarify briefly: This whole thread is simply a tweak to "my proposal", and it has been misunderstood by some due to my colorful miss-use of English. I want to tie density to sprinkler height and area to occupancy: Area LH=1000, OHI=1500, OHII=2000, density .008 gpm/s.f. times sprinkler height in feet. This is what I have come to realize from some limited modeling I've done so far, and it gets rid of the QR Reduction at 20' glitch. It is the reason I said I think the demands are too high for low ceilings and too low for high ceilings. I am not sure about the actual testing phase of the whole process, but I am not advocating any new products. (And when the head pops, we usually have far more than 7 psi Pt on it). Thanks again George, Brad -----Original Message----- From: George Church [mailto:[email protected]] Sent: Monday, June 04, 2012 3:10 PM To: [email protected] Subject: RE: 7psi Minimums for Fire Sprinklers You DO understand the cost of the path ahead of you, especially when you're trying to get fire tests done? There is a large item you may have missed: Economic feasibility Since I'd guess there is but a small number of these sprinklers that would be sold in a year. Various manufacturers have their own little "Edsels" that they invested R&D $ into, but aren't getting the return for them. Even when times are good, they are prudent about what they invest in, and I'm not certain that saving a couple PSI is one of them. If they have enough water to make the plumbing work, they've got 7 PSI up to a certain flow. But for the cost required to get the listing done and the sprinkler on the market, you'd prolly need a quantum change in the min EHP, not 2 PSI. It would look better as a % saved (save 28% of your EHP!) but when it comes right down to it, its 20% of what we generally leave as a throwaway cushion. I have had a lot of ideas I scrapped quickly because of the risk/reward economic viability measure. At one time, folks were putting up bar joists with the chords made of pipe so we could connect and use them as our sprinkler system, I believe in the 80's. Obviously, that idea's time hasn't come (yet). We see very few commercial multipurpose systems, despite what appears at first to be great cost savings. I keep a pad of paper and a pencil in the drawer of my nightstand. I don't remember the last time I awoke with an idea great enough to write down, but maybe I just sleep better than I used to. Or I've grown to appreciate rolling over and going back to sleep. George L. Church, Jr., CET Rowe Sprinkler Systems, Inc. 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