Fire pump for irrigation use?

[Southside]

So for the fire fighters on here, will a 1250 GPM fire pump work well as an irrigation pump?  Have a chance to pick one up and I was thinking of connecting it to a Cummins 6BT since it has a 1800 RPM rating and making a stand alone unit with it for summer irrigation - at some point I fear all of this rain we have been getting will shut off like a faucet.  This would free up a tractor and towed 540 RPM pump I use.  

Are they designed for continuous duty?  Will they draw water or do they need a positive pressure input?  Do they need filtration of some kind beyond normal irrigation screens?  Would it be realistic to expect 1250 GPM at 100 PSI output say 2000' away at a 2" gun nozzle?  We use both 100 size portable guns and 200 size gun on a big reel, all fed by a 6" main.  Sure would be sweet to be able to run them all at the same time.   

[Old Greenhorn]

Wow, SS you have a LOT of questions in there, I will try to hit what I can. The pump should do what you want. I expect with the difference in RPM's it will be a bit louder. Most of these portable pumps are made with 2-3/4 or 3' lines in mind. Is the one you are looking at set up for 6"? The pump will draw a suction for priming (takes one to five or more minutes depending on lift height) but then should hold the prime if you have no air leaks on the suction side.
 To calculate the output pressure, you will need to know the input, the line size, and the length, nozzle bore also plays into this (the GPM rating on the nozzle). These formula's are easily found. Google for "fire hose friction loss" there is also some loss (or gain) as the elevation changes.
 Your gun nozzle term confuses me. Is it a 2"straight bore (round opening) or is it some kind of spray nozzle? To give a good answer, I would have to go back through my pump operators textbooks and do the calculations, but I would need a little more detail about that nozzle first. ^" inch line is pretty big stuff, a gallon of water and 9 pounds per foot. It would take 2000 gallons to fill that line before one drop comes out the other end.
 As far as filtration goes, keep fish, frogs and sand out of the line if you can. The fish and frogs cut your flow down, the sand will eventually kill the impeller on the pump. SO the answer you want is pull clean water and use at least some kind of filter screens to keep out large stuff. The water does not have to be crystal clear, just free of foreign material that would hurt the pump (shale is VERY bad, don't ask me how I know this).
 Does that help you at all?

[A-z farmer]

South side logger
I do not know about fire pumps but are parts availed for the one you want to use .Here in New York anything fire related is very expensive to fix.i am sure it is because of regulations .
We do not use our irrigation every year and only use it for sweet corn .We used to use the 100 rain birds but now we use the 2 inch guns with solid set .i know this does not answer your question but we have three irrigation units and can still get parts for them 
Zeke

[Bandmill Bandit]

There are pumps that can be and are used for both applications AND pumps that are specific to each application. 

What is the brand and model of the pump you are considering? That will be the quickest way to get you a meaningful answer and can probably be had from the pumps manufacturer quite easily. 

[Southside]

Bandit - the sellers "representative"  : didn't have much info but was going to get me the tag info on Monday.  They are a split case design from the photos and he said they were installed in a large, commercial building for fire suppression but were too big for the water source so they had to downsize, that is all I know at the moment, except they are painted red.

OG - looks like a 4" in and out from the photos, my PTO pump has a 4" in and a out with a coupler to a 6" run from there, the suction line has a stainless screen around it with probably 1/4" holes.  It does take a few minutes to purge the system when first firing it up, have to watch the pressure gauge and you can tell when the air is out and then gradually raise the pressure via the RPM's.  The pump feeds 6" aluminum pipe with 3" risers where you want them that the stationary guns mount to, they have a 7/8" wide open hole (100 size guns) that the water squeezes through at the end of the nozzle, just a stream coming out for 100' or so, they do have a big, weighted "wacker" that breaks the stream and causes the gun to shift so you get a circular pattern.  Those each can take about 300 GPM.  The reel is a Rain Star, has an additional 900' of 4" hard hose on it that you stretch out at the beginning of a run and it pulls itself back in while it irrigates using some of the water.  That one has a 1.5" wide open hole at the very end (200 size gun) and makes up to a 500' diameter spray pattern and would take all 1200 GMP alone if I wanted.   

I was thinking if I used a love-joy to hook the pump to the Cummins then it would turn the pump at  1800 RPM and be in it's power band, allowing me to basically water 30 or so acres at a turn by only having to roll out the reel twice - sure would be a time saver.   We water the pasture and rotate the cows so the water delivery source needs to be able to move easily.  

[Bandmill Bandit]

One of the more common split case pumps in this area that got used for irrigation and fire obligations was Paco. Good pump but they were known to be cheap on the acquisition side and rather costly to keep running for continuous use in irrigation. We referred to them as a disposable mostly because the replacement parts were not the same quality as OEM. for Fire applications they did well because they did not get real heavy continuous heavy. 

BUT I did a quick search and discovered that Paco is now merged/owned by GrundFos (as of 2006) so they will be good pump since that happened.


      

[florida]

I had a 5 story building I maintained about 10 years ago. It had a fire pump on the first floor that we had to test once a month. It was so loud people on the 5th floor would leave while we ran it.  We used earmuffs to go into the fire control room to turn it on and off and even with the muffs the noise was terrible. I asked our fire maintenance people about it  and they said it was normal. 

[Southside]

So the pump is an AP Aurora, Pentair  Pump Group, says it has not been run in 8 or 9 years and that was for only a couple hours then. Tag says 231 ft of head at 1250 GPM, single stage, had a 60 HP 3 phase hooked to it.

Any thoughts? 

[yukon cornelius]

A 60 hp electric motor is the equivalent to a 120 hp gas. I dont have much experience with electric fire pumps but I do know a bit about fire trucks. A lot of trucks were built with pressure and a volume mode. Our old 1965 was the first i knew of it. A good pump will pull 15 feet of suction elevation. You will need hard suction tubing for the inlet for pulling from a reservoir or any time there is not pressure coming to the pump. Good gaskets in the connections. There are floating suction strainers to keep it from pulling debris from the bottom. Other methods are to tie a float onto the end. Your suction should be as large as the main inlet. I know of several fire trucks used for irrigation and I think they would be great for it.

[Southside]

Thanks Yukon,

I am going to take a look at it on Wednesday.  I have a spare 6 BT Cummins, 175 ish HP, that I figure I would love joy it to as a power plant.