This is an issue that has been lurking in the shadows for a while. The 24” is the maximum width of a flue. The 3.5 ft dimension is still in play but only for defining the type of rack. SO if you have too narrow an aisle, the fire will jump the aisle so the criteria for the individual rack type is expected to be inadequate for the larger overall assembly. For example, you have 2 single row racks (SRR) that are separated by a 30 inch aisle. The overall assembly is classified as a double row rack (DRR). So in attempting to apply the DDR criteria, where do you place the longitudinal in-rack sprinklers? The TC said this cycle that in-rack sprinklers shall be located only in flues so you can not place them in narrow aisles. Now lets say you have 5 DRR with 30” aisles. The overall assembly is a multiple row rack (MRR). The MRR criteria is typically equally spaced in-racks down the transverse flue (often at 10 ft). We know you must have an in-rack at the intersection of the longitudinal and transverse flues to have effective protection of a DRR. So WHERE do we place the in-rack sprinklers among these close DRR's that are called a MRR. Beats the dog foo out of me as did trying to get this addressed during this cycle. Pushing a 500 lb rock uphill can be easier than getting the majority of 30 people to see the problem much less fixing it. Yea I’m still a little frustrated.
Roland Huggins, PE - VP Engineering American Fire Sprinkler Assn. --- Fire Sprinklers Saves Lives Dallas, TX http://www.firesprinkler.org On Aug 6, 2014, at 4:27 AM, Martinez, Dewayne <[email protected]> wrote: > After checking the definition 3.9.3.7.1is 3.5ft the magic number? > > -----Original Message----- > From: Sprinklerforum > [mailto:[email protected]] On Behalf Of > Martinez, Dewayne > Sent: Wednesday, August 06, 2014 6:10 AM > To: [email protected] > Subject: rack flue space width > > NFPA 13 (07ed) > > Double row racks > > Is there a limit to how wide a flue space can be between double row > racks before you have to figure protection in each rack individually? > > > > I am figuring a job where 2 sets of double row racks have a 2' wide flue > space between them due to columns. > > > > Thanks, > > Dewayne > > > > > > > > _______________________________________________ > 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
