Brian, I use HydraCalc also and find it the easiest to run separate calcs for each system that have a common calc point in both. Get each calc close to 1 PSI of each other at that common point and then use "cut and paste" to add the rack to the overhead calc. I can then run a combined calc that is fairly close to being balanced. When I try to run a combined calc right from the start I find it much harder to balance it. Dewayne
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Brian Harris Sent: Wednesday, April 20, 2011 9:07 AM 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)
