I don’t think Gregg is worried about the first 36” below sprinkler for spray pattern development. I think he is probably more concerned with the rules stating obstructions X wide need to be located Y distance horizontally from sprinkler. When a new tenant comes in, they like to run their new lights and ducts all over the place without a care in the world and a box checker comes in and says an ESFR sprinkler is obstructed even though the new light/duct is more than 10ft below the sprinkler and is only 30” wide (not a problem for CMDA sprinklers).
My personal opinion is if you follow the obstruction rules so the pattern can fully develop (aka first 36”). Then the other obstruction rules for ESFR shouldn’t apply in a light/ordinary hazard occupancy. With the exception that if the obstruction is over 4ft wide then sprinklers need to be under them. However, I do not believe this stance is explicitly stated in NFPA 13. But can any sane person really argue that a sprinkler that will dump more than 100gpm can’t “control” an OH fire where the CMDA sprinklers that max out at 23gpm can. I’ve heard the naysayers argument, “ESFR is 12 sprinklers over 1200sq.ft which is a fast response sprinkler over a smaller area to quickly extinguish a fire”. Okay then, my argument is I am installing large K-factor sprinklers 25K@7psi. I will calculate 5 per line (50ft > 46.5ft) over 3 lines (1500 sq.ft.). I will still flow less water than the original ESFR system was designed for and have a remote area equal to what is now required by LH/OH CMDA sprinkler design. Plus I am also putting at least 4x the amount of water on a fire to “control” it. That 30” duct doesn’t seem to be much of an issue to me anymore. Like I said before, my opinion only. I am only on the committee for “NFPA ? - Wondering Why This Wasn’t Implemented When The Allowance For The Other Associated Issue Was”. Thanks, Sean VG From: Sprinklerforum [mailto:[email protected]] On Behalf Of Matthew J Willis Sent: Wednesday, August 31, 2016 11:17 AM To: 321; [email protected] Subject: RE: ESFR - Ordinary Hazard Especially since Chapter 8 and rules are divided by the Sprinkler Type, not hazard. R/ Matt From: Sprinklerforum [mailto:[email protected]]<mailto:[mailto:[email protected]]> On Behalf Of 321 Sent: Wednesday, August 31, 2016 12:14 PM To: [email protected]<mailto:[email protected]> Subject: Re: ESFR - Ordinary Hazard I would think that the obstruction rules of NFPA 13 Ch 8 would apply to the ESFR (i.e. 36" clear below deflector) regardless of the hazard. ESFR's were developed and listed by U.L. with additional room below the head to allow for the "Discharge Umbrella" to develop. Just my opinion... John W. Farabee, On Wednesday, August 31, 2016 1:37 PM, Gregg Fontes <[email protected]<mailto:[email protected]>> wrote: 2016 NFPA 13 – 8.4.6.6 Occupancy and Hazard. (Handbook) In an existing warehouse building being converted to a non-storage use, the existing ESFR sprinklers can remain in place provided the new use is either light or ordinary hazard. My questions is if it is ordinary hazard occupancy, do the ESFR obstruction rule apply or due the obstruction rules for standard systems apply (i.e. conventional)? As an example, would 30” x 48” lights be allowed to hang below the ESFR sprinkler and not be considered an obstruction? Same with new duct work greater than 24”? Etc. Thanks, Gregg Fontes Cen-Cal Fire Systems, Inc. 209-334-9119 _______________________________________________ Sprinklerforum mailing list [email protected]<mailto:[email protected]> http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
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