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 <mailto: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 <mailto:matthew.will...@ferguson.com> <matthew.will...@ferguson.com <mailto:matthew.will...@ferguson.com> > Sent: Thursday, March 09, 2023 12:37 PM To: sprinklerforum@lists.firesprinkler.org <mailto: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 <mailto:matthew.will...@ferguson.com> www.FergusonFire.com <http://www.fergusonfire.com/> From: Anthony Johnson <mountainfirepr...@gmail.com <mailto:mountainfirepr...@gmail.com> > Sent: Thursday, March 9, 2023 11:24 AM To: sprinklerforum@lists.firesprinkler.org <mailto: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 <mailto:sprinklerforum-le...@lists.firesprinkler.org>
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