This all sounds like engineering overthink to me. It's an obstruction less than 48" in dimension in at least one direction of the horizontal plane(s) it describes. If the horizontal plane of the deflectors are the required distance above the upper horizontal plane of the obstruction (be it duct, catwalk, cantilever, cloud, soffitt, etc.) then sprinklers are not required below per the prescriptive code that applies in this case.
I once asked AFSA for an informal interpretation of the following scenario: A large room with 47" by the length of the room ductwork running in parallel, each 1" apart, that essentially covered the entire room. This meant an inch from the wall to a 47" wide duct, and then another inch to another 47" wide duct and so on all across the room. The rest of the scenario met deflector distances, et. al. per 13. The conclusion, penned by either Roland or Phil Brown, was that this was perfectly acceptable under the rules of 13 and did not require sprinklers below the ductwork. Now this is a very unlikely scenario (I'd say less the a fraction of 1% chance in my made up statistics toy box), nor do I think it would be good practice if someone was to actually build something to the scenario,but the point is no sprinklers required below. And then when we go to a hallway and storage in a hallway. My presumption is the lockers have doors and locks (hence storage locker) because people storing their goods there do not want other people taking said goods (I tend to put no longer wanted stuff out on the road with a sign that says: "Free. Or Best Offer." and it magically disappears, sometimes along with the sign, and that is irksome), so they're unlikely to leave their things in the hallway. And it's five feet wide. If a head goes off I'm pretty confident there's going to be more water than the average person wants and the 36 inches (I believe that was the width of the obstruction–the length is irrelevant per the rule) of furiously burning methylethyldeath stored down the center of the corridor would still be contained within the parameters of a design area (1500 sqft at three feet wide would be a corridor 500 feet long or 300 feet at five feet wide. On Fri, Aug 21, 2015 at 7:01 AM, IPA <[email protected]> wrote: > Width, per nfpa 13, is the shorter of the two dimensions. > > > On Thu, Aug 20, 2015 at 10:55 PM, å... .... <[email protected]> wrote: > > > Your self-storage building feature a hallway-cloud design with > financially > > inconvenient prescriptive sprinkler implications. > > > > What about the "width" as measured n the direction parallel with the > > hallway? The obstruction length in that direction exceeds 4 feet. > Though > > stored goods in quantity should not be in the hallway for substantial > > amounts of time, and if a fire were to occur in > > hallway-located-combustibles, the fire likely would not advance into the > > storage rooms (liquid fuels being the exception, but even then there are > > sprinklers in the storage rooms). If I were writing the specification > for > > bid on this project, I would have declared that sprinklers cover the > > 60-inich wide hallway at the lower cloud level before they covered the > > hallway at the obstructed ceiling level. > > > > > > Scot Deal > > Excelsior Fire/Risk Engineering > > _______________________________________________ > > 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 > -- Ron Greenman Instructor Fire Protection Engineering Technology Bates Technical College 1101 So. Yakima Ave. Tacoma, WA 98405 [email protected] http://www.bates.ctc.edu/fireprotection/ 253.680.7346 253.576.9700 (cell) Member: ASEE, SFPE, ASCET, NFPA, AFSA, NFSA, AFAA, NIBS, WSAFM, WFC, WFSC They are happy men whose natures sort with their vocations. -Francis Bacon, essayist, philosopher, and statesman (1561-1626) A problem well stated is a problem half solved. -Charles F. Kettering, inventor and engineer (1876-1958) _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
