I haven't seen any rely to your question, so I'll take a stab. First, I'm not sure where the 30" obstruction width originated.
As I understand it, if your obstruction is more than 30" wide you would need a sprinkler under it, unless there was at least 18" of clearance from the deflector to the top of the obstruction, as illustrated in Figure A.8.6.5.1.2, which only came into play in the 2010 edition of NFPA 13. Possibly, if the obstruction isn't too deep, you can omit the sprinkler below if you can comply with Table 8.6.5.1.2 and Figure 8.6.5.1.2(a). Larry Keeping -----Original Message----- From: Sprinklerforum [mailto:sprinklerforum-boun...@lists.firesprinkler.org] On Behalf Of Brian Harris Sent: October-21-15 3:16 PM To: sprinklerforum@lists.firesprinkler.org Subject: Obstructions Against Walls Where does the maximum 30" dimension come from in figure 8.6.5.1.2(b) (2007)? What if you have the exact same scenario that's shown there but the width is say 36"? Per code I need to then apply 8.6.5.1.2 & 8.6.5.1.2(a) up to a width of 48" correct? After that heads would have to be installed under the obstruction right? Just for giggles 8.6.5.1.2(2) comes in handy but where do you draw the line with regard to how far the deflector is above the obstruction when you apply it? Would you use the 36" limit from 8.6.4.1.1.3 or is there no limit if heads are on both sides of the obstruction? Brian Harris, CET BVS Systems Inc. Sprinkler Division bvssystemsinc.com<http://bvssystemsinc.com/> Phone: 704.896.9989 Fax: 704.896.1935 _______________________________________________ Sprinklerforum mailing list Sprinklerforum@lists.firesprinkler.org http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list Sprinklerforum@lists.firesprinkler.org http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
