My 2 cents. . .

Question #1: If a space is built with no finishes and the intent is for that 
space to be finished at a later time, then I believe 8.15.20.1 is applicable.  

 

Question #2: I believe it’s prudent to include the tee in the calc.  When the 
space is finished and the ceiling is added, we try not to run/submit new 
calculations.  But when we do, the tee at the top of the new drop has to be 
included.  There may or may not also be an offset and a couple elbows on the 
new drop.  Typically we gain a few psi from the lower elevation of the new 
sprink, but lose psi in friction loss in the offset/drop/elbows.  Ultimately, 
as long as the hazard hasn’t increased, I don’t think we should design/install 
a system that has to be beefed-up in some way in order to make new 
tenant-finish calcs work.

 

OK, that was closer to 3 cents.

 

Ed Kramer

Bamford Fire

 

From: Sprinklerforum [mailto:sprinklerforum-boun...@lists.firesprinkler.org] On 
Behalf Of Kyle.Montgomery via Sprinklerforum
Sent: Wednesday, February 05, 2020 10:07 AM
To: sprinklerforum@lists.firesprinkler.org
Cc: Kyle.Montgomery <kmontgom...@aerofire.com>; Bruce Verhei 
<bver...@comcast.net>
Subject: RE: [EXTERNAL] Re: Shell Spaces and Bushed Outlets

 

Yeah, for the first part of my question about 8.15.20, I agree. 

 

But I realize that the easy answer there is that the tee probably makes little 
difference, so why not just include it in the calc. So I figured I would spice 
it up since we actually do run into this type of scenario from time to time.

 

So it’s really two questions that can be considered independently:

 

1.      Does NFPA 13 require minimum 1” outlets in shell spaces?

2.      If I have a sprinkler installed in a bushed outlet, do I need to 
include the equivalent length for that tee in my calculations.

 

-Kyle M

 

From: Sprinklerforum [mailto:sprinklerforum-boun...@lists.firesprinkler.org] On 
Behalf Of Bruce Verhei via Sprinklerforum
Sent: Wednesday, February 5, 2020 9:01 AM
To: sprinklerforum@lists.firesprinkler.org 
<mailto:sprinklerforum@lists.firesprinkler.org> 
Cc: Bruce Verhei <bver...@comcast.net <mailto:bver...@comcast.net> >
Subject: Re: [EXTERNAL] Re: Shell Spaces and Bushed Outlets

 

K-17. That’s a little different than I expect. I always thought more like parts 
of a strip mall building that might end up OH-2.

 

Best.


On Feb 5, 2020, at 07:58, Kyle.Montgomery via Sprinklerforum 
<sprinklerforum@lists.firesprinkler.org 
<mailto:sprinklerforum@lists.firesprinkler.org> > wrote:

That’s the crux of my question. A literal interpretation could say that the 
sprinkler is no longer connected directly to the tee, so you have to include 
the equivalent length for the tee in the calculations. But is that really the 
intent in this scenario? Is the bushing really creating an impact to the 
hydraulics? It seems strange to me that the type of fitting the sprinkler is 
connected to (welded outlet, threaded tee, threaded elbow) is of no concern to 
the hydraulics, unless the fitting has a bushed outlet. Does a threaded tee 
with a bushing really create more friction loss than, say a saddle tee 
(mechanical tee)?

 

In a lot of cases it doesn’t make much of a difference, but every once in a 
while you run into a scenario where you’re upgrading an area that had 1” 
outlets to something that needs a large orifice sprinkler (like a K17) and if 
you have to add the friction loss for a 1” tee into your calc it really does 
have an impact.

 

-Kyle M

 

From: Sprinklerforum [mailto:sprinklerforum-boun...@lists.firesprinkler.org] On 
Behalf Of J H via Sprinklerforum
Sent: Tuesday, February 4, 2020 3:41 PM
To: sprinklerforum@lists.firesprinkler.org 
<mailto:sprinklerforum@lists.firesprinkler.org> 
Cc: J H <design.azfire...@gmail.com <mailto:design.azfire...@gmail.com> >
Subject: [EXTERNAL] Re: Shell Spaces and Bushed Outlets

 

That doesn't sound legit - I would keep the tee in the calculations. A bushing 
isn't really recognized as a fitting per table 23.4.3.1.1 - more like a 
transient fitting.

 

On Tue, Feb 4, 2020 at 1:22 PM Kyle.Montgomery via Sprinklerforum 
<sprinklerforum@lists.firesprinkler.org 
<mailto:sprinklerforum@lists.firesprinkler.org> > wrote:

Esteemed members of the fire sprinkler community,

 

NFPA 13 (2016 Edition) section 8.15.20 is basically telling us to provide 
bushed 1” outlets for sprinklers in shell spaces, right?

 

Section 23.4.4.8.1(9) tells us that friction loss can be excluded for the 
fitting directly connected to a sprinkler.

 

In your opinion(s), is it the intent of the standard that you have to add the 
friction loss for a tee into your hydraulic calculation if using bushings, 
since the sprinkler is no longer directly connected to the tee? Or is it 
acceptable to consider a tee with a bushing as one fitting for the purpose of 
hydraulic calculations.

 

Kyle Montgomery

 <image001.png>

Aero Automatic Sprinkler Co.

21605 N. Central Ave.

Phoenix, AZ 85024

Direct: 623.580.7820

Cell: 602.763.4736

kmontgom...@aerofire.com <mailto:kmontgom...@aerofire.com> 

 

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