If it weren't allowed there would be no equivalent lengths for backflows, meters, etc. where a straight flow is reduced and incurs a pressure penalty. Or how about a proportioner? Water just goes faster through the little piece, loses more pressure due to extra velocity at that point and you calc to se if it's too much. What would he say if the two inch had worked for the whole thing? You can't go small for six inches even though the calcs work but you can for umpty feet because the calcs work. Time for the discussion about regulators that don't understand what the regulated know but are the ones making the decisions? Or do we just sigh and hope for a brighter future?
On Thu, Nov 11, 2010 at 9:33 AM, Bamford Inc. <[email protected]> wrote: > This is similar to what they are doing at Bomgaars in Central City. > Installing a 6:" off of a 4" > > Thanks > > Roger > ----- Original Message ----- From: "George Church" <[email protected]> > To: <[email protected]> > Sent: Thursday, November 11, 2010 8:09 AM > Subject: RE: reduce then increase pipe sizes > > >> We've got a project where we need 8" UG for the calcs, and the main in the >> street is 6". 6x6 tap, increase to 8, we're on our way. The water purveyor >> is not going to replace a block or two of existing UG. >> And look at 13D systems- certainly not unusual to have a 3/4 UG supply >> increased to 1" for the sprinkler riser after the tee. >> >> glc >> >> -----Original Message----- >> From: [email protected] >> [mailto:[email protected]] On Behalf Of Cliff >> Whitfield >> Sent: Thursday, November 11, 2010 8:59 AM >> To: [email protected] >> Subject: RE: reduce then increase pipe sizes >> >> Todd, >> >> I've seen this done in the past. In fact, there are a lot of times when >> it's done by the water purveyors during a tap on the main underground >> line. >> Not sure of a specific code reference. If common sense is an option you >> can >> point to NFPA 20 that allows a smaller size supply to feed a fire pump (ie >> 6" line feeding an 8" pump) if you go a certain number of feet (in pipe >> diameters) back and increase the pipe at that point. >> >> I believe the whole basis for hydraulic calculations is that if you can >> prove it works within the boundaries set forth in the standards then it is >> acceptable. You can reduce pipe sizes to balance a system when you are >> working with foam. I don't think this is really any different. >> >> Cliff >> >> -----Original Message----- >> From: [email protected] >> [mailto:[email protected]] On Behalf Of Todd >> Williams >> Sent: Thursday, November 11, 2010 7:51 AM >> To: [email protected] >> Subject: reduce then increase pipe sizes >> >> I am working on an existing system where we have to tie in a new 2-1/2" >> main >> into an existing 3". Since they do not make a 3x2-1/2 mechanical tee, that >> option is out. My proposal is to utilize an existing plugged 2" outlet, >> install a 2 x 0-6 TxG nipple and then increase to 2-1/2". It works >> hydraulically with 18+ psi left over (reducing the 2-1/2" main not an >> option >> hydraulically). >> >> I don't see anything in the Code that states that it is not allowed. >> However, the AHJ says it isn't. Before I argue the point, am I missing >> something? >> >> Todd G. Williams, PE >> Fire Protection Design/Consulting >> Stonington, CT >> 860.535.2080 >> www.fpdc.com >> >> _______________________________________________ >> Sprinklerforum mailing list >> [email protected] >> http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum >> >> For Technical Assistance, send an email to: [email protected] >> >> To Unsubscribe, send an email to:[email protected] >> (Put the word unsubscribe in the subject field) >> >> _______________________________________________ >> Sprinklerforum mailing list >> [email protected] >> http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum >> >> For Technical Assistance, send an email to: [email protected] >> >> To Unsubscribe, send an email to:[email protected] >> (Put the word unsubscribe in the subject field) >> >> _______________________________________________ >> Sprinklerforum mailing list >> [email protected] >> http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum >> >> For Technical Assistance, send an email to: [email protected] >> >> To Unsubscribe, send an email to:[email protected] >> (Put the word unsubscribe in the subject field) >> > > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > For Technical Assistance, send an email to: [email protected] > > To Unsubscribe, send an email to:[email protected] > (Put the word unsubscribe in the subject field) > -- Ron Greenman Instructor Fire Protection Engineering Technology Bates Technical College 1101 So. Yakima Ave. Tacoma, WA 98405 [email protected] http://www.bates.ctc.edu/fireprotection/ 253.680.7346 253.576.9700 (cell) Member: AFSA, SFPE, ASCET, NFPA, NFSA, AFAA, ASEE, NIBS, WSAFM, WFC They are happy men whose natures sort with their vocations. -Francis Bacon, essayist, philosopher, and statesman (1561-1626) _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
