As gently as possible I have to say that the quoted text - "the more demanding design basis must extend 15 ft beyond its perimeter” pretty much tells us the answer. Having said that, you aren’t the first so the 2016 ed has a new Figure showing you go downhill for perimeters too. See Figure A.12.1.3.1.4
It isn’t the same FIRE hazard thus the change in discharge criteria The argument on its all the same hazard - aka high piled storage would mean we could treat Group A plastic the same as a Class 1 commodity. Roland Huggins, PE - VP Engineering American Fire Sprinkler Assn. --- Fire Sprinklers Saves Lives Dallas, TX http://www.firesprinkler.org <http://www.firesprinkler.org/> > On May 13, 2016, at 2:26 PM, [email protected] wrote: > > Forum, > > I apologize if this has been discussed already as I tried searching the > archives. All my hits were either not high piled storage, mix of high piled > storage vs other storage arrangements with a level ceiling, or two different > distinct roof heights. None of these match my scenario. So here we go…. > > For quick reference: > > NFPA 13 (2013) – 12.3 Adjacent Hazards or Design Methods. For buildings with > two or more adjacent hazards or design methods, the following shall apply: > 1) Where areas are not physically separated by a barrier or partition > capable of delaying heat from a fire in one area from fusing sprinklers in > the adjacent area, the required sprinkler protection for the more demanding > design basis shall extend 15ft beyond its perimeter. > 2) The requirements of 12.3(1) shall not apply where the areas are > separated by a barrier partition that is capable of preventing heat from a > fire in one area from fusing sprinklers in the adjacent area. > 3) The requirements of 12.3(1) shall not apply to the extension of more > demanding criteria from an upper ceiling level to beneath a lower ceiling > level where the difference in height between the ceiling levels is at least > 2ft. > > What is your opinion on this rule when you have a warehouse that is 45ft > tall, roof slope is ¼ in 12, rack storage of class IV commodity (no solid > shelves or open top containers), ESFR protection, at the 40ft roof elevation > you change k-factors, so below 40ft the system is designed for K17@52psi for > 35ft storage height @ 40ft roof, and above 40ft the system is designed for > K22@40psi for 40ft storage height @ 45ft roof. There is no floor to roof > barrier between areas. > > Do you think the K22 design can stop at the 40ft roof height? Or, should the > K22 design be extended 15ft further into the area where the roof height is > 40ft or less? > > I have heard both sides of the argument. > · No 15ft extension. It is the same hazard “high piled storage”. > The k-factor change is okay right at 40ft. > · 15ft foot extension should be applied. Going to a higher storage > height and higher roof height requires different design parameters that are > more stringent than the lower roof and storage height, so the higher design > requirements should be carried over. > · Both sides agree to keep K-factors on different sprinkler systems > so you don’t overflow either system respectively. > > Let me know your thoughts. > > Thanks, > Sean VG > > > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > <mailto:[email protected]> > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org > <http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org>
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