Steve, I have been doing sprinkler design for over 50years and our NZ Standard/Rules have been based on FOC/UK rules for most of that time. Only in recent years have we adopted FM/NFPA for some of our Extra High Hazard.
Hence I think of Mains (usually 65 - 200+mm nominal bore) as feed pipes and Ranges (usually 25 - 50mm nb) as pipes which have sprinklers attached either directly or by droppers/risers. Of course Storage/ESFR sprinklers have now made us use 65 and 80mm nb pipes with sprinklers directly attached. Cheers, Russell Gregory From: Sprinklerforum [mailto:[email protected]] On Behalf Of Steve Leyton Sent: Friday, 28 October 2016 6:13 AM To: [email protected] Subject: RE: Hydraulic losses when using a Mechanical Tee on Sprinkler Outlet Russell: What does the term "range pipe" refer to? Steve Leyton -------- Original message -------- From: Russell & Carol Gregory <[email protected]> Date: 10/27/16 1:31 AM (GMT-08:00) To: [email protected] Subject: Hydraulic losses when using a Mechanical Tee on Sprinkler Outlet 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
