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)

Reply via email to