To expand on what Todd and Ken said. With regards to Flex drops in the standard, I know NFPA 13 (2013) 9.2.1.3.3 calls them "Flexible Sprinkler Hose Fittings". It's an assembly. Two fittings on each end of a flexible hose. Which is used in lieu of hard pipe and fittings. The sprinkler attaches to one fitting which can be ignored per NFPA allowanced stated in this chain. Manufacturer gives you the equivalent pipe length of the flexible hose since you don't have hard pipe, this shall be included in calculations. The other fitting is a straight flow fitting which has no additional friction loss per NFPA. You shall account for the friction loss of the tee you tie into at the branchline.
My opinion since the standard is clear as mud. Thanks, Sean VG From: Sprinklerforum [mailto:[email protected]] On Behalf Of Todd Williams Sent: Thursday, October 27, 2016 9:35 AM To: [email protected] Subject: Re: Hydraulic losses when using a Mechanical Tee on Sprinkler Outlet [https://tr.cloudmagic.com/h/v6/emailtag/tag/1477586127/01c6e4fe7e8b46e8dfef813adf427213/ecdd64c309bb34b23eb65c654267bfff/2a1db83817de6e290e02216f5e252a4c/9efab2399c7c560b34de477b9aa0a465/ufo.gif] Ken, I think your term is correct and NFPA needs to adjust. A 6' long fitting is a bit of a misnomer. Todd G Williams, PE Fire Protection Design/Consulting Stonington, CT 860-608-4559 On Thu, Oct 27, 2016 at 11:54 AM, Parsley Consulting <[email protected]<mailto:[email protected]>> wrote: Todd, I agree completely with your thoughts. Perhaps my use of the other term was my old-school nature. One of the PI's submitted to change the requirements for seismic protection would make flexible fittings mandatory in areas where the Cp value is greater than 0.50. While there may be some information to suggest that is a valid approach, it isn't the only option to account for the seismic impact of a drop to supply a sprinkler through a ceiling. It is, however, the one which carries a significant cost increase (materials and installation), and has an equally expensive hydraulic impact. The ballots for chapter 9 (soon to 18) changes haven't been issued yet, however I would wager this one is going to draw significant objections from those of us in seismic country. sincerely, Ken Wagoner, SET Parsley Consulting 350 West 9th Avenue, Suite 206 Escondido, California 92025 Phone 760-745-6181 Visit our website<http://www.parsleyconsulting.com/> On 10/27/2016 8:08 AM, Todd Williams wrote: [https://tr.cloudmagic.com/h/v6/emailtag/tag/1477580928/01c6e4fe7e8b46e8dfef813adf427213/ecdd64c309bb34b23eb65c654267bfff/d8888a303655f69b6fdfcea0f001c45a/9efab2399c7c560b34de477b9aa0a465/ufo.gif] Ken, I brought that up because in NFPA 13, they are called "flexible fittings" not "flexible drops". My thinking is that FUBAR Fire Protection (or someone like them) is going to try to claim the since NFPA call them fittings that they won't have to include them in the calcs. Todd G Williams, PE Fire Protection Design/Consulting Stonington, CT 860-608-4559 On Thu, Oct 27, 2016 at 10:55 AM, Parsley Consulting <[email protected]><mailto:[email protected]> wrote: Russell, Mark and Todd are both correct. If the sprinkler is directly attached to the fitting, in this case the welded outlet or mechanical tee, the friction loss through that fitting is excluded from the hydraulic calculations, per NFPA 13, 23.4.4.7.1(9). I don't know that I've ever had a set of calculations sent back with a comment that I didn't include the friction loss equivalent for the welded outlet or mechanical tee which was directly attached to the sprinkler. Todd's comment is valid as well, however it's worth noting, I believe, that when you're designing a system with flexible drops you must account for the equivalent length of the device, using the manufacturer's data. My own experience has been that those values are substantial. sincerely, Ken Wagoner, SET Parsley Consulting 350 West 9th Avenue, Suite 206 Escondido, California 92025 Phone 760-745-6181 Visit our website<http://www.parsleyconsulting.com/> On 10/27/2016 1:30 AM, Russell & Carol Gregory wrote: I posted a message on this subject early this month but only received one reply(thanks Brad). This was surprising as I thought it was a serious problem if the full EQL for tee had to be added to calculations. Especially if the change was made on-site after design had been completed with welded outlets. So my query is as follows; When calculating a Range Pipe with welded threaded outlets for sprinklers it is not necessary to include a loss for the water leaving the range pipe and entering the sprinkler. The total pressure is assumed to apply to the sprinkler orfice. This means that a 80nb pipe with a 25nb outlet and a k36 sprinkler does not have an additional loss added for the outlet fitting. If I change my design and fabricate the 80nb range pipe with 80 x 25 Mechanical Tees for the Sprinkler outlet do I have to apply an additional loss factor for that fitting? The published EQL for Mech tees varies greatly between brands,( 0.8m up to 2.4m). This means a head pressure of 345kPa would need around 600kPa in the range if this additional loss is added. Questions; 1. Is it common practice in USA to use 80 x 25 clamp/mechanical tees for attaching large bore Storage Sprinklers directly to 80nb range pipes? 2. Is it common practice to add in an additional loss for the clamp tee, in the hydraulic calculation, where the sprinkler is directly fitted to the tee outlet? I would appreciate the Forum members advise as to what is the standard practice in the USA. Russell Gregory Christchurch New Zealand e-mail [email protected]<mailto:[email protected]> _______________________________________________ Sprinklerforum mailing list [email protected]<mailto:[email protected]> http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected]<mailto:[email protected]> http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
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