Kevin, That's true for most of the sprinklers in the diagram but look at figure A.3.3.206.6 (2019) - the farthest loop from the supply has sprinklers on it and it's connecting both loops - those sprinklers are receiving water from two mains. Likewise, per the definition of a main the only main in Ed's example is the center line. Everything else are looped branchlines per the definitions.
JH On Wed, Oct 27, 2021 at 9:09 AM Kevin Hall via Sprinklerforum < [email protected]> wrote: > The annex shows the branch lines fed by the cross main from two directions, > the sprinkler can still only receive water from one direction from the > branch line... that is the distinction in the definition. > > The above is my opinion and has not been processed as a formal > interpretation in accordance with the NFPA Regulations Governing Committee > Projects. This is provided with the understanding that the AFSA assumes no > liability for this opinion or actions taken on it and they are not to be > considered the official position of the NFPA or its technical committees. > AFSA cannot provide design or consulting engineering services, and this > opinion should therefore not be considered, nor relied upon, as such. > > > Kevin Hall, M.Eng., P.E., ET, CWBSP, PMSFPE > > Coordinator, Engineering and Technical Services > > American Fire Sprinkler Association > > [email protected] > > 214-349-5971 > > > On Wed, Oct 27, 2021 at 12:05 PM J H via Sprinklerforum < > [email protected]> wrote: > > > I have a problem with the simplified definition floated out here that a > > grid system is one that feeds a sprinkler from two directions because of > > the illustration of a looped system in the annex of '13 which shows > > sprinklers attached to the end portion of the loop resulting in those > > sprinklers receiving water from two directions. Technically the only > cross > > main is the center piping - everything else are looped branchlines. I > would > > be prepared for kickback from a knowledgeable AHJ. I would personally > avoid > > a design like this if at all possible to avoid the headache of hashing it > > out w/ an AHJ. But if it's the difference between a system like this and > a > > fire pump it might be worth the fight. > > > > JH > > > > On Wed, Oct 27, 2021 at 6:04 AM Sean Conlin via Sprinklerforum < > > [email protected]> wrote: > > > > > If you were to put caps on the left and right lines going north and > > south, > > > it resembles a compound gridded system and a sprinkler can receive > water > > > from both sides. > > > > > > The east and west lines are essentially the mains and so is the 4" in > the > > > middle. > > > > > > Yes is has a looped piping arrangement and is symmetrical but it is a > > > gridded system by NFPA-13 definition. If you were to not tie the lines > > > together, it would be a loop. > > > > > > Regards, > > > > > > Sean W. Conlin > > > E:[email protected] > > > > > > This message, including any attachments is considered confidential and > > for > > > use only by the intended recipient(s). > > > Any other distribution, copying or disclosure is strictly prohibited. > > > Please delete this communication and notify > > > Demand Sprinkler Design Inc. if you are not the intended recipient or > > have > > > received this message in error. Demand > > > Sprinkler Design Inc. accepts no responsibility or liability for any > loss > > > or damage from use, including damage from viruses. > > > > > > -----Original Message----- > > > From: Ed Kramer <[email protected]> > > > Sent: October 26, 2021 1:31 PM > > > To: [email protected] > > > Subject: Gridded dry system > > > > > > Is this sprinkler system a gridded system? I've avoided this type of > > > design in the past for dry systems because it 'kinda' a grid, but not > > > really. Now I'm questioning my questioning. What are your thoughts? > > > > > > > > > > > > Reference NFPA 13 (2019) sections 8.2.3.10 and 3.3.206.5. > > > > > > > > > > > > > https://www.dropbox.com/s/u2hw3cbvlga4fcq/Dry%20Attic%20System.pdf?dl=0 > > > > > > > > > > > > > > > > > > Ed Kramer > > > > > > > > > > > > > > > _______________________________________________ > > > 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 > _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
