Re: Pump, Tank, 1000 ft suction line.....

lamarvaughn Wed, 08 Jun 2011 20:44:09 -0700

No matter how you look at it or calc it,you either forget about the 6"suction pipe size or move the pump & tank closer together.Maybe that'swhy #20 normally illustrates a pump house near a tank.It's not just tofit it on the page,it may just be the power of suggestion.

LV



On Wed, Jun 8, 2011 at 7:12 PM, IPA wrote:

George, what did you mean by "Don't think you'd have a need to provide

positive suction head at 150%." Doesn't NFPA #20 5.14.3.2 require itto stay

above 0 (or -3 for tanks) while flowing 150%?

On Tue, Jun 7, 2011 at 10:43 AM, George Church<[email protected]>wrote:

It may- its been 10 years+ since they let me run HydraCAD back there.
Did you call NH and ask em?

One of the strengths they offer is someone who understands theprogram

answering your call.

You could pretend the tank is a piece of UG and is the incomingsupply- set

your flow test up to be 10,000 GPM at .5 PSI or 0 PSI
Run it thru the UG including the slop you need to get positive head
exceeding the friction loss in the supply piping
Ignore the warning of low suction-

Check result for positive pressure to the fire pump at system demand.Don't

think you'd have a need to provide positive suction head at 150%.


George L.  Church, Jr., CET
Rowe Sprinkler Systems, Inc.
PO Box 407, Middleburg, PA 17842
877-324-ROWE       570-837-6335 fax
[email protected]



-----Original Message-----
From: [email protected] [mailto:

[email protected]] On Behalf Of RalphyHenderson

Sent: Tuesday, June 07, 2011 1:00 PM
To: [email protected]
Subject: RE: Pump, Tank, 1000 ft suction line.....

No, I don't need a PC to do the calc but I'd like for hydra calc toshowall this w/o an additional set. Things like that tend to confuse theAHJ's -especially hand written things. You would think a multi thousanddollarprogram would be able to take the calc from a tank to the pump and tothe

system in one report - but it looks like that's not the case.







--- On Tue, 6/7/11, George Church <[email protected]> wrote:

From: George Church <[email protected]>
Subject: RE: Pump, Tank, 1000 ft suction line.....

To: "[email protected]"<[email protected]>

Date: Tuesday, June 7, 2011, 4:47 PM

Why not take a piece of paper, write down the length of the run,multiply

it by the FL/ft, and use a calculator to multiply the two and get the
friction loss?
Then correct for any dif in elevation by multiplying the dif x .433.

It really isn't that hard and you really don't need a pc to run asimple

supply calc.

Ok, maybe I should say you SHOULDn'T need a pc....


George L.  Church, Jr., CET
Rowe Sprinkler Systems, Inc.
PO Box 407, Middleburg, PA 17842
877-324-ROWE       570-837-6335 fax
[email protected]



-----Original Message-----
From: [email protected] [mailto:

[email protected]] On Behalf Of RalphyHenderson

Sent: Tuesday, June 07, 2011 12:29 PM
To: [email protected]; [email protected]
Subject: RE: Pump, Tank, 1000 ft suction line.....

Bob,

That's kind of what I was getting at. I'll probably just have tosubmit aseparate calc showing the 150% pump rating through the pump to thetank toprove the losses are acceptable. Does anyone know if there is a wayto do

this in a single calc in hydracalc? I can put in an additional water

'source' but then would have to enter in a static, res, and flow forthetank to get it to run through the program and these numbers areunknown

(except for static).

Thanks,

RB


--- On Mon, 6/6/11, Bob <[email protected]> wrote:

From: Bob <[email protected]>
Subject: RE: Pump, Tank, 1000 ft suction line.....
To: [email protected]
Date: Monday, June 6, 2011, 11:05 PM

Ralph,
Looking at this I'm coming up with 20.3 psi loss in 1000' of pipe not
counting fittings and valves.

(4.52*1000.00^1.85)/(140^1.85*6.4^4.85) = .0203 .0203 * 1000 =20.3. 6.4"is ID of 6" Tyton Joint Pipe DI. Fittings and valves will increaseyourlosses. At 1500 gpm you will have .43 psi / ft loss. These numberswillvary depending on pipe type and ID. As far as how to do it; I thinkI wouldsimply run the numbers through the calculation back to the tank. Orbetteryet, if there are hydrants fed off of the tank have a flow testperformed

and calc back to that point of connection.

Bob Knight, CET III
208-318-3057
www.firebyknight.com


-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Vince
Sabolik
Sent: Monday, June 06, 2011 4:37 PM
To: [email protected]; [email protected]
Subject: Re: Pump, Tank, 1000 ft suction line.....

Ralph -

My rough calcs say about 16 psi loss at 100% flow and 34 psi loss at150%

flow.

Unless this is an elevated tank, or your source is uphill from thepump,

this won't work.

At 06:32 PM 6/6/2011, you wrote:

at 1000 gpm, you are going to lose about 2 psi per 100' of 6"
ductile iron pipe.  At 1500 gpm, you are going to lose about 5 psi /
100' of DI pipe.  You need to have enough elevation between the tank
and pump to provide a positive pressure at the suction flange.

On 6/6/2011 3:28 PM, Ralphy Henderson wrote:

Hi All,

Can someone explain to me how one would go about calculating a fire
pump being fed solely from a water storage tank but with a 6" x
1,000 ft suction line? I've calculated fire pumps off of tanks that

had a small 10 ft. suction lines directly off the tank but neverone

with this amount of underground line and I'm concerned about making
sure friction losses in the suction are properly accounted for. The
pump is 75 psi @ 1000 gpm.

We use hydracalc, and typically when a fire pump and tank scenario
comes up we have only one 'source', the pump, being specified.
Would this change in this instance? I guess the main thing I'm

concerned about is coming up with a negative pressure at thesuction

flange due to such a long run.

Any help?

-RB

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Vince Sabolik
Christi Fire Protection, Inc.
11351 Pearl Road
Strongsville, Ohio 44136

T 440 572-7730  F 440 572-7719  Email:
<mailto:[email protected]>[email protected]

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