Yes, but every time a piece of pipe is changed the computer recalculates a new end head pressure. It's kind of like playing whack-a-mole. Guess I prefer the old way to make sure.
Ron Fletcher Aero Automatic Phoenix, AZ -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Trevor Spain Sent: Wednesday, April 20, 2011 8:33 AM To: [email protected] Subject: Re: Balancing Rack Calc's I haven't used every hydraulic calculation program on the market but I assume all of them will let a designer examine Pt and q for every head. Assuming a designer knows what they've typed in, detecting a large imbalance should be easy to detect from examining this information and reported system demand flow. I certainly can see a lazy designer failing to do this, though ... after all, the computer is infallible, right? Trevor Spain Igneus Incorporated On 4/20/2011 10:23 AM, Ronl.Fletcher wrote: > Yes but when the computer hashes it out you can't tell how much of an > imbalance you have. The computer adjusts the end head pressure so things > balance at the connection causing overflow in one system or the other, unless > you get really lucky. I would always calc each system, make sure they balance > at the connection then let the computer hash it out. I've seen rack systems > that require 420 gpm minimum use over 600 gpm and the designer says "well > it's balanced at the base of riser". > > Ron Fletcher > Aero Automatic > Phoenix, AZ > > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Matt Grise > Sent: Wednesday, April 20, 2011 7:33 AM > To: '[email protected]' > Subject: RE: Balancing Rack Calc's > > Brian, > > I have seen that it matters which has the higher pressure for exactly the > reason you are describing (when adding racks to an overhead system). If one > requires too high a pressure, it may overflow the other enough to blow the > calc. > > I agree with the others though... if you can, just build the entire system > into one model and let the computer hash it out. > > Matt Grisé PE*, LEED AP > Sales Engineer > Alliance Fire Protection > 130 w 9th Ave. > North Kansas City, MO 64116 > > *Licensed in KS& MO > > 913.888.0647 ph > 913.888.0618 f > 913.927.0222 cell > www. AFPsprink.com > > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of > [email protected] > Sent: Wednesday, April 20, 2011 9:25 AM > To: [email protected] > Subject: RE: Balancing Rack Calc's > > Brian, > > If this is a new system with roof& rack systems,then calc them as 1 > system,adjust pipe size to give the required demand at each area and no > other balancing is needed.It's when you are adding a rack system to an > existing roof system riser that balancing is required.I was told by F.M. > years ago that if the 2 systems were within 1 PSI of each other,they > would not ask for a seperate balancing calc.Good luck. > > Lamar Vaughn,SET > > > On Wed, Apr 20, 2011 at 10:12 AM, Brian Harris wrote: > >> Travis- >> I'm using HydraCalc >> >> Brian Harris >> FDFP Inc. >> >> -----Original Message----- >> From: [email protected] >> [mailto:[email protected]] On Behalf Of Travis >> Mack, >> SET >> Sent: Wednesday, April 20, 2011 10:10 AM >> To: [email protected] >> Subject: Re: Balancing Rack Calc's >> >> What calc program are you using? Just put both the rack and overhead >> system >> in the calc file and let the computer balance. >> It has been over a decade since I did a 'separate' calc for each. >> Travis Mack, SET >> MFP Design, LLC >> www.mfpdesign.com >> >> Sent on the SprintR Now Network from my BlackBerryR >> >> -----Original Message----- >> From: "Brian Harris"<[email protected]> >> Sender: [email protected]: Wed, 20 Apr 2011 >> 10:06:42 To:<[email protected]> >> Reply-To: [email protected] >> Subject: Balancing Rack Calc's >> >> I knew sooner or later my luck would run out and I'd have a job with >> racks, >> yes ladies and gentlemen this is the first time I've had to do an in >> rack >> system. I've searched through code, searched past archives, and still >> am not >> all warm and fuzzy with my conclusion, if someone would be so kind as >> to >> either give me either an amen or send me to the corner with a dunce >> cap I >> would greatly appreciate it. >> >> >> I have done my overhead calc's, done my rack calc's, they are balanced >> to >> within .5 psi of each other at a common point on the riser. My >> question is >> this: does it matter which calc has the higher of the two pressures? >> The >> reason I ask is when it comes to the combined calc and you balance the >> flow >> at the common point on the riser I have tried two scenarios, if the >> higher >> pressure is on the rack system and you plug in the "balance" formula I >> get >> 981 gallons I need to add to the rack system which will work. If I >> tweak a >> couple things and the overhead system is the higher pressure and plug >> that >> into the "balance" formula I get 181 gallons that I need to add to the >> overhead system and that will not work. What is the consensus of the >> forum? >> >> >> Brian Harris >> >> First Defense Fire Protection >> >> 11957 Ramah Church Road >> >> Huntersville, NC 28078 >> >> Phone: 704.948.3506 >> >> Fax: 704.948.3507 >> >> Nicet # 128476 >> >> >> >> >> >> >> ======= >> Email scanned by PC Tools - No viruses or spyware found. >> (Email Guard: 7.0.0.21, Virus/Spyware Database: 6.17320) >> http://www.pctools.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) >> >> >> >> >> >> ======= >> Email scanned by PC Tools - No viruses or spyware found. >> (Email Guard: 7.0.0.21, Virus/Spyware Database: 6.17320) >> http://www.pctools.com/ >> ======= >> >> >> >> >> >> ======= >> Email scanned by PC Tools - No viruses or spyware found. >> (Email Guard: 7.0.0.21, Virus/Spyware Database: 6.17320) >> http://www.pctools.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) > > _______________________________________________ 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)
