Just bantering with ya... 'But then ask him how many full scale tests have we run simulating light hazard scenarios.' I'd hope he'd answer about 6,000 per year. (extrapolating data from a city I used to be familiar with)
'then the rules must work!' For LH and OH that's a rather good argument. Not much to make better, re 6,000 test a year in LH. Although, there have been improvements, QR reduction, LH and OH 3 times rule exception, no o-rings, EC heads... I'm sure there are others. 'If there's one thing we are getting our hands around..it is storage' yep and why? I'd highly doubt it was because those in the field had some great foresight. I'd guess epic failures, 1,000+ in-racks being broken off a year (there's money to be made with a better mouse trap) and 500-1000 test a year with a significantly higher number of failures than the light hazard testing (there's money to be saved in Mr. Contractor/Insurance not buying new warehouses). These factors showed a lot of room for improvement THEN the industry started taking a closer look. 'when to stop looking below the deflector' regular old heads don't bother me as much as ESFR when it comes to that. 'That's the only reason the 4ft rule is has survived over 100 years.' Oh, say, it's reasonable for most situations and understandable for a layout tech and installer may not be the reason? Let's go back to 1895 don't ya think there needs to be some limit? You say 8' I say 2' we compromise at 4' and 100 years later I think there is no money to be made or saved by going to 6' and no history in 100,000's of test showing a problem needing to go to 3'. Why does the sun rise in the East? 'cuz orbital mechanic requiring it to come up someplace. Why 52,000, why 400 sq.ft., why 1-12" 'cuz it has to be something given the limited engineers available that can run FDS. 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 Steven Scandaliato Sent: Wednesday, October 09, 2013 4:08 PM To: [email protected] Subject: RE: Sprinklers Below Overhead Doors Folks, you are missing the picture here...no one said it was an AHJ who asked the question! Lets not make that jump, cause I have volumes of pictures from contractor installations that would make you change your name. The point here is that NFPA 13 does not say when to stop looking. 13 does not tell you after so many feet in the air you don't have to put them in even though it wasn't until the early to mid 90's that we were actively pursuing full scale testing above 45 feet and that was all storage testing at that. Why 45ft you say? cause that was the height of the roof deck at the testing lab! and on top of that we have no clue if heads in a mall with a ceiling height of 60ft is going to work...sure we can model it and make some safe assumptions and put a seal on it...but without burning it, we are guessing. Just like we were guessing with attic designs until we found out what was in the book for attics from the beginning actually burned down....three times. That doesn 't automatically mean we should stop putting them in...but we have to be realistic about how effective sprinklers will be at those heights given light hazards. Conversely, no where in 13 does it say when to stop looking below the deflector...in other words, after the golden zone of 18" at what point can we say...the pattern is developed. Take a look in chapter 8 at the minimum distances a sprinkler must perform for a listing at 7psi, I am traveling right now so don't have the reference but its the picture of a spray pattern that you have passed by hundreds of times while looking for something else.. somewhere around 8.5 I think. Digest that a minute. The point I am making is that this 4ft rule, which ole Joe Hankins shared with me years ago, had nothing to do with duct work or conference tables. Look at the diameter of the spray pattern at 18" down and then 4ft down. The fact is you can give James G at Tyco or any of his counterparts a storage configuration and he will be one of the few that has a chance at getting close to what will happen. But then ask him how many full scale tests have we run simulating light hazard scenarios. You will think your phone lost its signal. Do we really need to put sprinklers under a duct that is 49" wide and 24" off the ground? This is my point. We cannot claim ignorance at one group or another...it is the condition of prescriptive codes and standards that is at fault here. My first cycle I was on the committee we went to dinner one night and I got sat down next to Chet. As we talked he said something to me that stuck like pipe dope to my door handle...and that was in the world of prescriptive codes, once something makes it into the book, good luck ever taking it out (hence the difference in size from 1970 to now) because the measuring stick after it gets in their is that if people are not dying and buildings are not burning down...then the rules must work! That's the only reason the 4ft rule is ha s survived over 100 years. Just look at the difference between the storage chapters and the rest of the book. If theres one thing we are getting our hands around..it is storage. But light and ordinary are left guessing, hoping, modeling, wondering......the answer to the original question is still put a head under the door and omit it from the calcs....but ya gotta love how we get there!Whew...almost missed the plane! Ciao,Scan > From: [email protected] > Date: Wed, 9 Oct 2013 11:48:36 -0500 > Subject: RE: Sprinklers Below Overhead Doors > To: [email protected] > > Too many times, bottom line for owner's................Low bidder...... > > > David Autry > > Meininger Fire Protection Inc. > 2521 W L St. Suite No.4 > Lincoln, Ne 68522 > Voice (402) 466-2616 > Fax (402) 466-2617 > [email protected] > > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of > Todd > - Work > Sent: Wednesday, October 09, 2013 11:23 AM > To: [email protected] > Subject: Re: Sprinklers Below Overhead Doors > > Unfortunately, "experienced" and "responsible" are vague terms and > open to too much interpretation. It is incumbent on the property > owners not to hire bozos, unfortunately, that does not always happen > > Todd G Williams, PE > Fire Protection Design/Consulting > Stonington, CT > www.fpdc.com > > On Oct 9, 2013, at 11:59 AM, David Autry <[email protected]> wrote: > > > From my 1961 Edition: > > > > (in bold print no less) > > > > 1421. Sprinkler system layout and installation should be entrusted > > to none but fully experienced and responsible parties. Sprinkler > > system installation is a trade in itself. Inspectors cannot be > > expected to act as working superintendents or correct errors. > > > > > > David Autry > > > > Meininger Fire Protection Inc. > > 2521 W L St. Suite No.4 > > Lincoln, Ne 68522 > > Voice (402) 466-2616 > > Fax (402) 466-2617 > > [email protected] > > > > -----Original Message----- > > From: [email protected] > > [mailto:[email protected]] On Behalf Of > > Cahill, Christopher > > Sent: Wednesday, October 09, 2013 10:37 AM > > To: [email protected] > > Subject: RE: Sprinklers Below Overhead Doors > > > > I wish I could find my 1936 copy. That was in there. Well it went > > more like this...sprinklers are their own trade and shall be > > installed by only those trained and experienced. AHJ is not a field > > superintendent and is not expected to supervise the work. OK maybe > > yours improves with bringing AHJ into the knowledgeable. > > > > Chris Cahill, PE* > > Senior Fire Protection Engineer > > Burns & McDonnell > > 8201 Norman Center Drive > > Bloomington, MN 55437 > > Phone: 952.656.3652 > > Fax: 952.229.2923 > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkl > er.o > rg > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkl > er.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
