This is actually pretty dramatic Ron. In Russell's case, if the K25 head is in a 1" welded pipe-o-let the pressure required at the branch line is the same as at the head, where as if it is in a 1" mechanical tee the pressure required at the branch line is the same as if the head was on a 1" x 11'-0" sprig or drop!
Of course if the K for a K25 was established when it was in a 1" mech tee, it could rightly be excluded. Both welded outlets and mech tees have similar hole sizes, but I think the gaskets on mech tees reduce the AREA of the hole, which plays the biggest part of the ultimate Coefficient of Discharge, aka, K-Factor. Just my two no nonsense :) Brad On Oct 29, 2016 11:02 AM, "rongreenman ." <[email protected]> wrote: > Are we once again worrying about the difference between 0.003 psi and > 0.004 psi? > > If I recall the number we're trying to compare demand against supply is > based on a formulae with a constant (average), an average C-factor of > deterioration based on variable conditions over many years, a nominal > diameter, and a velocity pressure determined by holding a pitot in a stream > of water that's trying to rip the pitot out of your had while you take an > average reading from a bouncing gauge that has a +/– built in. Then we do > the math, round to the nearest 50 gpm, and apply it to a graph so small > that the width of the line has an effect. > > And as Brad said the fitting is calculated into the K factor of the > sprinkler. And as someone else noted the flexible drop is a drop, not a > fitting. It has a fitting the sprinkler screws into. It also has a friction > loss value that has to be an average as it doesn't take the curves into > account. And do we calculate the gain from the elevation change? > > On Fri, Oct 28, 2016 at 8:33 AM, Brad Casterline <[email protected]> > wrote: > >> Here is my original reply, for what it's worth... >> >> >> >> >> >> Russell, >> >> >> >> My understanding is we do not have to figure the loss for the fitting the >> >> sprinkler is in because when the K Factor was being established it was in >> a >> >> fitting. >> >> NFPA 13 (2016) 23.4.4.8.1 (9) confirms that. >> >> But it's a good question because we're supposed to use a manufacturer's >> >> published loss if they have one. >> >> So would it make sense to, if the published loss is greater, subtract the >> >> loss shown in 13, and include that difference? >> >> >> >> Brad >> >> >> >> >> ------------------------------ >> >> *From:* Sprinklerforum [mailto:sprinklerforum-bounces >> @lists.firesprinkler.org] *On Behalf Of *Brad Casterline >> *Sent:* Friday, October 28, 2016 10:19 AM >> *To:* [email protected] >> *Subject:* RE: Hydraulic losses when using a Mechanical Tee on Sprinkler >> Outlet >> >> >> >> Here is the e-mail I sent to our in-office guy whom submits questions to >> NFPA: >> >> >> >> >> >> ***** >> >> "From NFPA 13- 2016 >> >> >> >> >> >> *23.4.3.1.1 *Table 23.4.3.1.1 shall be used to determine the >> >> equivalent length of pipe for fittings and devices unless manufacturer’s >> >> test data indicate that other factors are appropriate. >> >> >> >> *23.4.4.8.1* >> >> (9) Friction loss shall be excluded for the fitting directly >> >> connected to a sprinkler. >> >> >> >> >> >> A 1" tee in the table is 5' equivalent length. >> >> A mechanical tee with 1" outlet is 11' equivalent length. >> >> >> >> If the sprinkler is directly attached to the mechanical tee do we still >> exclude it?" >> >> ***** >> >> >> >> >> >> When we got the recent response Gregory pasted, I asked the guy for the >> exact wording of the submitted question, but since submitting a question >> on-line 'disappears' once submitted, it was not available. He said he >> reworded mine a little, but thinks the last line (which is what this is all >> about) was clear. >> >> >> >> Personally, I like my original reply to Russell, but I'm just a Tech, so >> there's that :) >> >> >> >> Brad >> >> >> >> >> ------------------------------ >> >> *From:* Sprinklerforum [mailto:sprinklerforum-bounces >> @lists.firesprinkler.org] *On Behalf Of *Russell & Carol Gregory >> *Sent:* Thursday, October 27, 2016 10:01 PM >> *To:* [email protected] >> *Subject:* RE: Hydraulic losses when using a Mechanical Tee on Sprinkler >> Outlet >> >> >> >> Ken, and others, >> >> We have been excluding the loss for a welded outlet or a mech tee when a >> sprinkler is directly attached. If the outlet is to feed a pipe (regardless >> of length) then the standard loss for a branch on tee would be used, >> however if the Manufacturers Data Sheet states that the loss in a clamp tee >> is greater than the loss in Table 23.4.3.1.1 (NFPA 13 2016) for a side >> outlet of tee, THEN the ADDITIONAL LOSS shall be included. I think they >> should say the Higher EQL Loss should be used so you don’t use less than >> the Table Loss. >> >> >> >> Here is a recent NFPA Response to a similar question; >> >> >> >> Table 23.4.3.1.1 is required to be used to determine the equivalent length >> >> of pipe for fittings and devices unless manufacturers' test data indicate >> >> that other factors are appropriate. In your situation since the >> manufacturer >> >> specifies an equivalent length of 11 feet, you are required to use 11 feet >> >> for the equivalent length. >> >> >> >> In regards to Section 23.4.4.8(9) of the 2016 edition of NFPA 13, if an >> >> extension is used with a tee, that tee must be included in the hydraulic >> >> calculations. The allowance to use an extension is restricted to >> sprinklers >> >> with a relative low discharge volume. They will most likely be used for >> >> minor adjustments to interface with the ceiling. >> >> >> >> This answers some of the other Forum responses to my questions but does >> not answer my problem. >> >> >> >> What I would like to see is a practical flow test done with a K36 (us >> k25) head and see if there is a significant difference between welded >> outlet, threaded tee and clamp tee. Does anyone know if this has been >> done??? >> >> >> >> Our AHJ has asked for the full loss to be included and this will nearly >> double the pressure required at a K-36 sprinkler from 345kPa(50psi) to >> around 600kPa(90psi), if clamp tees are used. There is quite a variation >> between Brands for the stated EQL. >> >> Makes life difficult if site staff change from welded to mechanical >> fittings and then buy a variety of brands!!!!! >> >> >> >> Thanks for the responses. >> >> Russell Gregory >> >> >> >> >> >> *From:* Sprinklerforum [mailto:sprinklerforum-bounces >> @lists.firesprinkler.org] *On Behalf Of *Parsley Consulting >> *Sent:* Friday, 28 October 2016 3:56 AM >> *To:* [email protected] >> *Subject:* Re: Hydraulic losses when using a Mechanical Tee on Sprinkler >> Outlet >> >> >> >> 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 <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] >> >> >> >> >> >> _______________________________________________ >> >> 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 >> >> > > > -- > Ron Greenman > > 4110 Olson Dr., NW > Gig Harbor, WA 98335 > > [email protected] > > 253.576.9700 > > The Universe is monstrously indifferent to the presence of man. -Werner > Herzog, screenwriter, film director, author, actor and opera > director (1942-) > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler. > org > >
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