Dane is correct. We get this question a lot through the Technical Review submissions, and the response is pretty cut and dry.
The three times rule does not apply to non structural members in light and ordinary hazard occupancies and because the deflector is located above the duct, water is able to spray on both sides, so it can be considered a noncontinuous obstruction. No additional protection is not required. -Kevin On Thu, Mar 9, 2023 at 5:08 PM Greg McGahan <g...@genesisfireservices.com> wrote: > With all due respect Dane - read the annex, it specifically addresses > that issue. > > On Thu, Mar 9, 2023 at 3:42 PM Dane Long <da...@bamfordfire.com> wrote: > >> Anthony, >> >> >> >> I feel there might be a few sections you need to look at regarding this >> question. >> >> >> >> For me I would start at *8.6.5.2 Obstructions to Sprinkler Discharge >> Pattern Development.* >> >> >> >> *8.6.5.2.1.1 *Continuous or noncontinuous obstructions less than or >> equal to 18 in. (457 mm) >> >> below the sprinkler deflector that prevent the pattern from fully >> developing shall comply with >> >> 8.6.5.2. >> >> >> >> The section above lays the ground work for the 18in requirement >> (8.6.5.2). Then I would look at *8.6.5.2.1.3* Minimum Distance from >> Obstructions.* >> >> >> >> *8.6.5.2.1.4* *For light and ordinary hazard occupancies, structural >> >> members only shall be considered when applying the requirements >> >> of 8.6.5.2.1.3. >> >> >> >> IMHO Because it specifically says “structural members only shall be >> considered” I believe the intent of this section is to allow for us to not >> provide sprinklers on both side to a reasonable degree, meaning we’re able >> to get water on both sides of the obstruction as long as its not a >> structural member. >> >> >> >> Thanks, >> >> >> >> >> >> >> >> >> >> *Dane Long, AET* >> *Engineering Technician *| *Bamford Fire Sprinkler Co., Inc.* >> P: *785.825.7710* >> F: *785.825.0667* >> A: *1383 W. North Street Salina, KS 67401* >> >> >> >> >> >> *From:* Anthony Johnson <mountainfirepr...@gmail.com> >> *Sent:* Thursday, March 9, 2023 2:26 PM >> *To:* Discussion list on issues relating to automatic fire sprinklers < >> sprinklerforum@lists.firesprinkler.org> >> *Subject:* [Sprinklerforum] Re: Duct obstruction criteria in LH attic >> >> >> >> The 3x rule is the only one we think would apply but it only applies to >> structural components. >> >> >> >> Best Regards, >> >> Anthony Johnson >> >> Mountain Fire Protection >> >> 'Saving Lives and Valuing Property' >> >> >> >> On Thu, Mar 9, 2023 at 12:58 PM Taylor Schumacher <tay...@sfsprinkler.com> >> wrote: >> >> When you cannot apply one of the obstruction rules, it does not mean that >> there isn’t an obstruction. >> >> >> >> If you think about this scenario the same way you would with sprinklers >> directly attached to a pipe, that’s where to start. Look at the 3x rule or >> sprinklers on each side. >> >> >> >> >> >> *Taylor Schumacher* >> >> Security Fire Sprinkler <http://www.j-berd.com/> >> >> 1 Industrial Blvd | Sauk Rapids, MN 56379 >> >> Office: 320.656.0847 | Direct: 320.640.7050 >> >> >> >> *From:* matthew.will...@ferguson.com <matthew.will...@ferguson.com> >> *Sent:* Thursday, March 09, 2023 12:37 PM >> *To:* sprinklerforum@lists.firesprinkler.org >> *Subject:* [Sprinklerforum] Re: Duct obstruction criteria in LH attic >> >> >> >> I believe however, the intent of the section must still be applied. Water >> on both sides. >> >> Not sure in the 13 edition the location, but in the 19 it is 10.2.7.1.2. >> >> We are referred back to it as applicable from the 3 times section. >> >> >> >> Sprinklers spaced on opposing sides, not to exceed the max half distance. >> >> >> >> R/ >> >> Matt >> >> >> >> *Please rate our customer service >> <https://survey.medallia.com/?emailsignature&fc=3539&bg=Fire%20and%20Fabrication>* >> >> >> >> *Matthew J. Willis, CWBSP, CET* >> >> *Engineering Designer IV* >> >> *FERGUSON FIRE DESIGN, LLC* >> >> *A Wholly Owned Subsidiary of Ferguson Fire & Fabrication, LLC* >> >> 401 N 5th Street >> >> Suite 448 >> >> Wausau, WI 54403 >> >> C: 307-236-8249 >> >> *matthew.will...@ferguson.com <matthew.will...@ferguson.com>* >> >> *www.FergusonFire.com <http://www.fergusonfire.com/>* >> >> >> >> *From:* Anthony Johnson <mountainfirepr...@gmail.com> >> *Sent:* Thursday, March 9, 2023 11:24 AM >> *To:* sprinklerforum@lists.firesprinkler.org >> *Subject:* [Sprinklerforum] Duct obstruction criteria in LH attic >> >> >> >> I have an elementary question but know there are varying opinions on the >> topic. The situation is a tight unused attic space in a LH occupancy. Our >> upright sprinkler deflector will be 3" above the ductwork. Evaluating all >> of the obstruction criteria presented in NFPA we've essentially came to the >> conclusion that the ductwork would not pose an obstruction but came to this >> conclusion mainly by process of elimination. The beam-rule would not apply >> since the ductwork is below the deflector. The 3X rule is only for >> structural components in light and ordinary hazards and the 'wide >> obstruction' rule would not apply since the ductwork is only 24" wide. >> That only leaves the 'suspended or floor mounted vertical obstructions' >> rule of 8.6.5.2.2 ('2013 ed) but it specifically mentions free standing >> partitions, privacy curtains and "similar obstructions". I don't think >> duct-work is a similar obstruction. I would like to have my ducks in a row >> if this design approach should be questioned but also want to make sure I >> have a sound design. Is our reasoning correct that essentially if the >> sprinkler deflector is above the duct water will spray on both sides and >> the duct would not pose as an obstruction? >> >> >> >> Best Regards, >> >> Anthony Johnson >> >> Mountain Fire Protection >> >> 'Saving Lives and Valuing Property' >> >> >> _________________________________________________________ >> SprinklerForum mailing list: >> >> https://lists.firesprinkler.org/list/sprinklerforum.lists.firesprinkler.org >> To unsubscribe send an email to >> sprinklerforum-le...@lists.firesprinkler.org >> >> >> _________________________________________________________ >> SprinklerForum mailing list: >> >> https://lists.firesprinkler.org/list/sprinklerforum.lists.firesprinkler.org >> To unsubscribe send an email to >> sprinklerforum-le...@lists.firesprinkler.org >> > > > -- > > Greg McGahan > > *Genesis Fire Services, LLC* > > *4912 Glover Lane. Milton, FL **32570* > > *P- 850-637-8535* > > *C- 850-712-9555* > > _________________________________________________________ > SprinklerForum mailing list: > https://lists.firesprinkler.org/list/sprinklerforum.lists.firesprinkler.org > To unsubscribe send an email to > sprinklerforum-le...@lists.firesprinkler.org -- Kevin Hall, M.Eng., P.E., ET, CWBSP, PMSFPE Sr. Manager, Engineering and Technical Services American Fire Sprinkler Association
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