John, You are a TC member yourself. If, as it seems, the interp of NFPA is that we do indeed include the published equivalent length for a mech tee with a sprinkler installed directly in it, that we just deem it ridiculous, because Steve said so?
By the way, I know Steve did not say so. This is all about rules and interpretations, is it not? Brad On Oct 29, 2016 2:13 PM, "John Denhardt" <[email protected]> wrote: > I could not agree more with Steve. It is fine to look at the details but > do not go beyond ridiculous. > > John > > John August Denhardt, P.E. > Strickland Fire Protection > > On Oct 29, 2016, at 1:03 PM, Steve Leyton <[email protected]> > wrote: > > There's a saying in our business that we design systems with computers, > use lasers to measure pipe for fabrication, then mark with a paint pen and > cut it with a chop saw. In other words there are some weak links in the > chain of events that we take for granted every day. > > The hydraulic design method that we use, the number of sprinklers and > sizes of design areas that we include in our models, all provide for > conservative safety factors. So to the point of whether or not a rubber > gasket reduces the inside diameter compared to a weld-o-let or a threaded > fitting, my reaction to that is so what, who cares? > > All these formulas and algorithms and commentary amount to a whole lot of > over-analysis and here's why: if you were to actually account for that > hundredth or thousandth an inch, the impact would be an almost > indiscernibly higher starting pressure at the end sprinkler. Thereafter, > you would have an almost indiscernible lower net K-factor at each > successive sprinkler thus reducing overflow,making the system demand lower > by a fraction of a fraction of a PSI here and a GPM there. > > So if you want to spend an extra 3 or 4 hours per calc boilng down these > metrics, be my guest but as far as this discussion thread is concerned I'm > pretty sure the horse is dead and beyond resuscitation. > > > Steve > > > -------- Original message -------- > From: "rongreenman ." <[email protected]> > Date: 10/29/16 9:44 AM (GMT-08:00) > To: [email protected] > Subject: Re: Hydraulic losses when using a Mechanical Tee on Sprinkler > Outlet > > In y experience with mech tees I always used the type with the lip so the > hole size was substantially bigger for it than a elder outlet and the > rubber was well away from the hole. That aside dramatic is a pretty heady > word Brad (pun intended). The fitting the head is screwed into, including > welded outlets and mech tees, do not need to be calculated per NFPA. Ig the > listing requires it then that would trump the standard but to my knowledge > no head requires that fitting be included. Given all the slop in the model > we use, and that it is a model I'm always amazed that a bunch of > engineering types act like it is an actual and mathematically accurate > representation of what goes in each piece of the system in all cases. > > On Sat, Oct 29, 2016 at 9:23 AM, Brad Casterline <[email protected]> > wrote: > >> 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-f >>>> iresprinkler.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-f >>> iresprinkler.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 > > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler. > org > >
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