Greg: A RPZ has NO (0) ability to relieve pressure on the discharge side (system side) after the #2 check valve. The only way for the intermediate relief chamber to relieve pressure from the other side of the #2 check (The discharge or system side) is if that check valve is leaking back into the intermediate chamber. That is not the normal operating situation. With expansion occurring on the discharge side of the #2 check, (In the AF system) the backflow should not relieve it, it will simply increase the system side pressure, further sealing the #2 check against backflow.
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Greg McGahan Sent: Friday, April 01, 2011 8:51 AM To: [email protected] Subject: Re: figure 7.6.3.4 - antifreeze loop with relief valve Ron, 2010 edition, you are correct it doesn't show in the previous versions. I respectfully disagree with both of your points on the RPZ in lieu of a relief valve. The purpose of the expansion chamber or as allowed in 2010 for systems less than 40 gal capacity, a relief valve is to prevent excess pressure build up in the AF Loop. The RPZ will release pressure if the pressure in the loop rises above that of the system pressure. Which serves exactly the same purpose with exactly the same results of the Pressure relief valve, meaning the pressure will go down and fresh water will fill the void. It isn't allowed and we are not doing it, but I think we should be able to. As to the height questions from earlier, the nice CE provided us a document from the air force - AF132-1066 that says that either the backflow is less then 5' high or a permanent platform is built to allow for testing and maintenance. Greg On Fri, Apr 1, 2011 at 9:08 AM, Ron Greenman <[email protected]> wrote: > The usual Greg. 7.6.3.4 of what edition? Now somebody will take the > time to figure it out and reply but I have every edition of 13 going > back to 1978 and I'm not the oldest guy out here, and I'd like to look > at the figure you refer to and see what you're talking about. Or I > could pull out my '78 and say it doesn't exist. The answer to your > second question is: > > Machine: The relief port is between the first and second checks and is > a low pressure relief, not high. > > Practical: Just using a relief dumps the expensive anti-freeze > solution which is then diluted when the pressure goes down and more > fresh water is introduced. > > On Fri, Apr 1, 2011 at 6:05 AM, Greg McGahan <[email protected]> > wrote: > > Does anyone know why if you use figure 7.6.3.4 with a relief valve, why > do > > you have to incorporate the loop instead of going straight like you can > if > > you have an expansion tank? > > > > And, if the backflow preventer is an RPZ, wouldn't it serve as the relief > > valve? > > > > Thanks, > > Greg > > > > -- > > Greg McGahan > > Living Water Fire Protection, LLC <http://www.livingwaterfp.com> > > 1160 McKenzie Road > > Cantonment, FL 32533 > > 850-937-1850 > > fax 850-937-1852 > > _______________________________________________ > > 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: > ASEE, SFPE, ASCET, NFPA, AFSA, NFSA, AFAA, 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) > -- Greg McGahan Living Water Fire Protection, LLC <http://www.livingwaterfp.com> 1160 McKenzie Road Cantonment, FL 32533 850-937-1850 fax 850-937-1852 _______________________________________________ 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)
