Remember we're talking about elevated water storage tanks, not a slab mounted 
bolted or welded steel tank.  

The 140ft we've been talking about is from the base of the storage tank to the 
ground below, 8" vertical riser from bottom of tank down to ground.


Craig L. Prahl, CET   
Fire Protection Specialist
Mechanical Department
CH2MHILL
Lockwood Greene
1500 International Drive
PO Box 491, Spartanburg, SC  29304-0491
Direct - 864.599.4102
Fax - 864.599.8439
[email protected]
http://www.ch2m.com 


-----Original Message-----
From: [email protected] 
[mailto:[email protected]] On Behalf Of 
[email protected]
Sent: Friday, August 07, 2009 7:20 AM
To: [email protected]
Subject: RE: water storage tank

This puts the hydrant outlet at least 10 feet below the base of the tank.  
Otherwise the residual pressure would not be possible?

Bill Brooks

 William N. Brooks, P.E.
 Brooks Fire Protection Engineering Inc.
 372 Wilett Drive
 Severna Park, MD 21146
 410-544-3620 Phone
 410-544-3032 FAX
 412-400-6528 Cell

   -------- Original Message --------
 Subject: RE: water storage tank
 From: <[email protected]>
 Date: Thu, August 06, 2009 4:04 pm
 To: <[email protected]>

 FWIW:

 I was digging through some old project data where we had some flow information 
from a similar arrangement.

 The 250,000 gallon elevated tank, B.O.T. was 140ft, with a 10" riser serving a 
10" underground fire main. Residual flow at the hydrant nearest the tank 
revealed approximately 2100 gpm at 65 psi.

 Loss through the 10" riser using HW would indicate about a 1.7 psi loss for 
the 140 ft.

 And BTW, the risers are usually steel not DI. So different C-factor, makes a 
little difference in the loss.

 Craig L. Prahl, CET
 Fire Protection Specialist
 Mechanical Department
 CH2MHILL
 Lockwood Greene
 1500 International Drive
 PO Box 491, Spartanburg, SC 29304-0491
 Direct - 864.599.4102
 Fax - 864.599.8439
 [email protected]
 http://www.ch2m.com


 -----Original Message-----
 From: [email protected]
[mailto:[email protected]] On Behalf Of Mark Sornsin
 Sent: Thursday, August 06, 2009 3:36 PM
 To: '[email protected]'
 Subject: RE: water storage tank

 The correct calculation is 0.156 x 14 not 140 (the formula given earlier was 
0.156 psi/10 ft.).

 So your loss through 140 ft. of cement lined ductile iron would be 2.2 psi at 
1,560 gpm.

 [that loss per foot of DI pipe seems a little high to me, but its prolly good 
enough for these purposes]

 Mark A. Sornsin, PE
 Fire Protection Engineer
 Ulteig Engineers, Inc.
 Fargo, ND
 Direct: 701. 280.8591
 [email protected]



 -----Original Message-----
 From: [email protected]
[mailto:[email protected]] On Behalf Of Greg McGahan
 Sent: Thursday, August 06, 2009 1:37 PM
 To: [email protected]
 Subject: RE: water storage tank

 You are correct....the answer I got was "we don't know"........from the 
horse's mouth. Thanks for all of your help, I will let you know how it works 
out in a few hours.

 Greg McGahan
 Operations Manager

 Living Water Fire Protection
 1160 McKenzie Road
 P.O. Box 877
 Cantonment, Florida 32533
 (850) 937.1850 | Fax (850) 937.1852 | Cell (850) 554.3231 
[email protected]



 -----Original Message-----
 From: [email protected]
[mailto:[email protected]] On Behalf Of Todd Williams
 Sent: Thursday, August 06, 2009 11:04 AM
 To: [email protected]
 Subject: RE: water storage tank

 Someone designed a water tank and they can't tell you the output? Who sold 
that design contract?


 At 11:18 AM 8/6/2009, you wrote:
 >I am getting info piecemeal from the engineering firm that is in charge  >of 
 >the tower. They say they don't Know what the residual pressure and  >flow 
 >will be when the tower is completed. We have a sprinkler system  >going in 
 >"next door" to the tower using the existing water from the old  >system. 
 >However, they have installed a 4" pipe with a hydrant instead  >of 6" (many 
 >years ago)and nobody knew until we dug it up.
 >
 >Now we are flowing 600 gpm through a 4" pipe to our source and the  >calcs 
 >are too close for comfort. We are looking for a "guesstimate"
 >of the available water at the base of the tower without any fittings or  
 >>valves. I can add them in the 8" line from the base to the new tie in  
 >>point where the systems tie together. We are talking about needing to  >pick 
 >up 5 to 10 psi not 20 or 30, so as long as we are close we should  >be good.
 >
 >This really should fall on the EOR, but as is often the case in this  
 >>region, if we want to finish the job on time, we have to get an answer  
 >>immediately.
 >
 >So I can say that I should reasonably be able to expect .156 x 140'
 >= 22 lbs of loss from the tank to the bottom w/o fittings....therefore  >if 
 >we say we should reasonably expect 1,500 gpm at 35 psi?
 >
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