Relay Pumping CAFS

[SBLG]

Does anyone have experience relay pumping CAFS?
We are taking delevery of a new CAFS pumper tanker in Aug-Sep in the units second due area we are wondering if it could act as a nurse tanker supplying CAFS to the first in unit.
My specific questions are:

1.) will the air in the cafs line cause the recieving pump to cavitate ? If so even at a idle ? At a idle can we just use it as a maifold.

2.) Will running the CAFS through the second impeller destroy the bubble structure reducing the effect of the CAFS?

Thanks Chris

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[This message has been edited by SBLG (edited May 31, 2000).]

[Romania]

You can't relay pump finished cafs, you'll have major problems with them forward pumpers pump. As for using the forward pumper as a manifold, you would have the same problems as with the using a fog nozzle, all your bubbles would break up. You can pump foam solution to you forward pumper and than have that engine inject the solution with air to make cafs.

So the answers to both your questions is yes. I would either have the CAFS rig become the first out rig, refit you first out with CAFS, or think about using Horz. Standpipes if your new engine can't make it to remote/restricted access locations. You can even have a smaller engine/mini-pumper lay a 2-1/2" up to the fire to save time and effort.

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Alan Romania, CEP
romania@uswest.net
IAFF Local 3449

My Opinions do not reflect the opnions of the IAFF or Local 3449.

[neiowa]

To revive a really old thread. Only thread I find on the subject. Is this correct info?

If can't relay from supply pumper (with CAFS) to the attack pumper (nonCAFS) then how far can you realistically pump CAFS thru a handline (1.75" or 2.5")? What friction loss table should you use?

[RFDACM02]

To revive a really old thread. Only thread I find on the subject. Is this correct info?

If can't relay from supply pumper (with CAFS) to the attack pumper (nonCAFS) then how far can you realistically pump CAFS thru a handline (1.75" or 2.5")? What friction loss table should you use?

It seems the issue is that the pumped CAF is in its finished state and needs to be as smooth a transition from the pump to the nozzle to remain bubbly? As descibed the excessive turns and valves would strip the air bubbles from the finished foam. In a hose lay there will be some stripping of bubbles, but I'd think far less without the numerous elbows, never mind passing through the impellors of a pump!

[npfd801]

I would think no matter what, all that air in the CAFS solution coming into another pump would be no different than when you cavitate the thing, which we all know is not good for your pump...

[Bones42]

There was a guy on here, i think by the name of Cafsfire or something like that, who claimed to have pumped CAFS through 1 3/4" hose for up to a mile. I want to say he was located somewhere in Texas.

[GreggGeske]

I have never tried or had a need to relay pump CAFS. You could in theory pump CAFS through a pump, but I would leave the pump dis-engaged, truly using it as a manifold. I do not know of any charts that show friction loss for CAFS. I believe there virtually is no friction loss until you get out to 4000 feet. There are minimum hose lengths that must be used when a static mixer is not used to get good quality mixed foam. All my first line engines now have CAFS so I would never need to relay, but we might have to try it just for the sake of discussion.

[BCFarmer]

We pumped CAFS through our Engine, but the pump was not engaged and was used as a manifold. The pump and plumbing stripped some of the bubbles from the hose stream, but it did make fairly good CAFS.

[Fire304]

Any air introduced into the pump will cause cavitation. Pumping CAFS will cause problems in the pump.

I have personally pumped a 2 1/2 line over 2000 feet long which split into two 1000 foot handlines at a brush fire and the nozzle men were asking me to gate it back, I was at idle. I hope someone from out West can verify this, but I've heard of forestry lays well in the thousands of feet as routine.

You may use your downstream truck as a manifold, as long as you have enough hose down stream from that truck to recombine the foam (see min hose length distances). You would be better off using a large gated manifold.

Better practice is to relay water, as CAFS is usually used where low volumes are required (frankly, in a structural fire anything more than 2 handlines and you should think about going to water). If you're pumping water and things go to hell in a hand basket, its very easy to switch to big water quickly. If you're pumping CAFS then you'd need to flow out what's in your supply line.