I don't have a standard available, I'm on a road trip, but I believe somewhere 
in 13 under hydraulic calculation methods is a paragraph which states that it 
is not necessary to include the fitting into which the sprinkler head is 
installed in the hydraulic friction loss calculation.

Mark at Aero
602 820-7894

Sent from my iPhone

On Oct 27, 2016, at 3:31 AM, Russell & Carol Gregory 
<[email protected]<mailto:[email protected]>> 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]>

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