Mini/quick attack Pumpers, are they worth it?

[Fire304]

That's an interesting thought cfire, but I don't know if class A foam will suds up in salt water. The only type of dish soap that will make good suds in salt water in lemon Joy, everything else just fizzels out, since Class A is mostly really strong soap it might not be compatible with the high mineral content of the water (think of ocean water as really really hard water). Non the less, you're right, you could make some really dry foam and fill compartments with it and not effect stability as much as with straight water (note, you will still effect stability, especially if the fire is above the water line, but you're right it is about 1/2 the weight of water). The only problem with it is that if you have a very hot fire it might consume the water content faster than you can apply it, often a problem with ship board fires (hence the really big guns). A better solution to ship board fires is a prepiped very high pressure water mist system which atomizes the water into a fine fog to cool the compartment and smother the fire.

Ah, if only my old shipping buddy drkblam was around to get into this conversation!

If you visit www.snuffer.com you'll see there is a small rescue boat that is equiped with a Snuffer CAFS unit in service.

resq14, been to their site lately? Several nice new rigs been delivered.

peon30, if I am not mistaken there is at least one major airport that has a Snuffer pickup for just that purpose.

[cfire3]

[QUOTE]Originally posted by Fire304
[B]That's an interesting thought cfire, but I don't know if class A foam will suds up in salt water.

Most of the clas A foams have advertisment that they are salt water compatable. I have used dawn at .5 % in Gulf salt water and we used Chemguard A plus in the Virgin Islands to fight a cargo boat fire.
I call the detergents in the class A's soap, too. Real soap is not so good in hard water. Big "bathtub ring" problems.



Non the less, you're right, you could make some really dry foam and fill compartments with it and not effect stability as much as with straight water (note, you will still effect stability, especially if the fire is above the water line, but you're right it is about 1/2 the weight of water).

At twenty to one expansion ratio, the foam is twenty times lighter than water and it fills twenty times more space.



The only problem with it is that if you have a very hot fire it might consume the water content faster than you can apply it, often a problem with ship board fires (hence the really big guns).

CAFS is NOT like water applications where you have to absorb heat faster than it's being created, the foam hits the fuel and sticks to it, sealing in the flamable vapors and that stops the source of the heat. Takes far less foam than water to do this, in fact water won't do it at all.


A better solution to ship board fires is a prepiped very high pressure water mist system which atomizes the water into a fine fog to cool the compartment and smother the fire.

Very high pressure systems are very dangerous to people near them and there was a series of scientic studies done a few years ago that showed the misting systems using tiny water droppets of water, which is made of hydrogen (an explosive gas) and molecules of oxygen (which makes hydrogen explosive) breaks down into its elements in supper heat and FEEDS THE FIRE. Which is why the huge volumes are needed.

[cfire3]

Oh! and CAFS will work with any of the class B foams as well.

AFFF and protein concentrates can be generated to look as thick as shaving creme and you can adjust the density anywhere in between running slurry to stackable foam. It works with the polar solvent type agents too, but flush the injectors after you use the polar foam, it dries into a crust but will rehydrate if you have time to wait.

[Fire304]

Thanks for the info on the compatibility of Class A foam and salt water, its nice to know that is a feasible back up if we ever get into that situation.

I was thinking 2:1 foam (typical CAFS foam for structural work is 2:1 or 3:1).

As far as CAFS not being like water in that it does a better job of sealing the fire you're right, but if the fire is producing more heat than the water can absorb before reaching the seat of the fire it will evaporate and not put a dent in the fire. Resq14 found this out first hand last Thursday night as he tried to enter a structure that was really too far-gone for a single CAFS line. CAFS is amazing stuff but its no magic bullet, you still need water to put fire out, and it still works primarily by absorbing the heat. This is why you "paint the room" as you enter a burning structure with CAFS, all that foam stuck to the walls and ceiling will suck up heat and cool the room down reducing the volume of fire you face. High expansion 20:1 foam has a further problem in that being so light it might just be sucked up by the updraft of the fire and blown out the vent.

In the confined space of ship fires often grow to intensities seldom seen ashore outside of industrial facilities. Metal walls reflect a good deal of the radiant heat back in towards fire in the incipient stage leading to flash over conditions in a fraction of the time an ordinary structure fire would take. Once at that stage the metal bulkheads and decking will conduct the heat into adjoining spaces creating exposures on all 6 sides of the fire compartment.

As a result, in the modern age of ship board firefighting we have trended away from handlines and interior attack to fixed systems which usually work by smothering the fire, such as Halon (now banned thanks to the Montreal Protocol), CO2, and AFFF or protein based foam deluge systems in high fire risk compartments.

Recently however, as Halon has been steadily disappearing from inventory water mist has become the standard replacement for fixed systems, especially in areas which would suffer massive damage from other water based suppression systems. Water mist is now the standard in all new US Navy engine and machinery rooms, and is also quite common on cruise ships where massive generators power the ship.

Water mist is not dangerous to occupants provided they are not within 3 feet of the discharge heads (usually located along the overhead and spray like a commercial pressure washer in a broad fan), and provided there are no toxic components to the fire, being in the compartment during discharge and suppression are no more dangerous than standing deck watch in a dense fog.

Spaces protected by water mist may be reentered immediately after activation without SCBA (again with the warning about toxic gases). Water mist does not cause severe corrosion in electrical components that some Halon replacements do.

Hydrogen shearing only occurs in extremely hot fires where the fire can overwhelm the water flow and can occur with any water application. All water mist systems should be installed with automated activation systems which detect and suppress fires very early on, other wise (as with any fixed system short of compartmental flooding with water) the fire can exceed the mist's ability to extinguish it.

We are starting to see water mist ashore now, the computer industry has seized on it, as has the cooking industry (both for its ability to rapidly contain and extinguish as well as its complete lack of harmful components). Many new Class K extinguishers are actually self contained water mist applicators.

Ships with high risk cargoes tend to have fixed systems in the cargo holds, but many other ships don't, as a result if a fire breaks out in the hold it can be quite some time before a meaningful suppression effort can begin. A prepiped system rigged to the fire mains would allow instant attack to all sections of the ship without the risk of harming the ship or compromising the stability.

[dmleblanc]

i dont know if this has been sugested yet or not, but how about using them to respond to car fires in parking garages?

I don't know about in your area, but by the time we get a parking garage in our area I'm sure the automaton cyborg firefighters can fly up to the appropriate level in their E-One HoverEngine and knock it out with their plasma extinguishers...

[SamsonFCDES]

Originally posted by dmleblanc


I don't know about in your area, but by the time we get a parking garage in our area I'm sure the automaton cyborg firefighters can fly up to the appropriate level in their E-One HoverEngine and knock it out with their plasma extinguishers...

Never gonna happen...

The Union will freak about robot FFs!!!

[dmleblanc]

Ah, but Samson, you forget about NFPA. Before too long they will come to the conclusion that certain types of emergencies (Structure fires, vehicle fires, industrial fires, any fires, any smoke, any call that involves actually leaving the fire station) are simply too dangerous for human beings to be involved in. In the future, in order to be NFPA compliant, all fire apparatus will have to come equipped with the aforementioned robotic firefighters.

Of course, some concessions will have to be made to tradition....the HoverEngine will be red, naturally, and have a "Q" siren mounted on the front. The android firepersons will be fitted with leather helmets, even though the standard titanium model is much cheaper and more effective.

And we still won't have a parking garage.....

[cfire3]

[QUOTE]Originally posted by Fire304
[B]

I was thinking 2:1 foam (typical CAFS foam for structural work is 2:1 or 3:1).

I think D. Colletti was the guy that started this confusion about how much air was in CAFS foam. It gets pretty confusing when you try to combine pneumatic (air) and hydraulic (water) formulas. I usually convert the foams cfm to gpm to get a better comparison. I use the multiplier 7.48 X c.f. to get how many gallons in a cubic foot of air. Then 3:1 comes out to 22.44 gallons of foam for each gallon of water, hence, = approx. 20:1 expansion ratio.




CAFS is amazing stuff but its no magic bullet, you still need water to put fire out, and it still works primarily by absorbing the heat. This is why you "paint the room" as you enter a burning structure with CAFS, all that foam stuck to the walls and ceiling will suck up heat and cool the room down reducing the volume of fire you face. High expansion 20:1 foam has a further problem in that being so light it might just be sucked up by the updraft of the fire and blown out the vent.

CAFS gets a little complicated and difficult to explain but I would like to try and see if this makes any sense. The old style of foam generator or foam nozzle or tube were engineered to produce a fixed expansion ratio or fixed amount of water through a sized venturi to suck in a fixed amount of air then agitate the mixture into foam with any velocity that's left. A 6:1 expansion was considered the max for tis type of foam maker. THe bubbles were large and very fragile so it required a lot of foam concentrate to make the bubble last about 5 minutes before they drained .25% of the water. If you designed a nozzle that made a bigger bubble like the high expansion devices, the bubbles were so fragile a match would burst a room full of the stuff, (exageration of course) but a good example. CAFS on the otherhand is made from the friction inside ordinary hose and pipes, this friction cause a high velocity core to agitate the solution and the bubbles that are formed by this intense agitation are VERY small compared to the other type of foam making equipment. The very small bubble are many times more durable simply because of their size and require about 300% less foam concentrate to keep them stable. That's why CAFS works with dish soap and about anything else that will foam at very low percentages. I use the concentrate ratios to adjust how fast I want the foam bubbles to release the water. I can make CAFS foam last for minutes to DAYS depending on the need.

Lets compare a mist drop with a tiny foam bubble. A mist drop is solid water with a radius exposed to heat, it absorbs heat until it explodes into steam or into elements. Lets not debate the hydrogen yet. The same amout of water will make a dozen CAFS bubbles each with a radius exposed to the heat. The bubbles are hollow and will heat faster than a solid drop. There is another aspect to complicate the comparison of a water drop and a foam bubble, it's the fire gases from the combustion that are water repellent, the smoke reppels water. If you smoke a piece of paper on both sides and dunk it into water it will not get wet. If you add soap to the water the soap molecule has an electromagnectic attraction to the carbon in the smoke. The smoked paper instantly gets wet. The CAFS foam has these soap molecule in the bubbles, they are attracted to the smoke and actually mix with it. So there is a whole lot more going on with CAFS bubbles than with the plain water they contain.

Botton line is when you paint a room with CAFS foam, you are cooling the SOARCE of the heat thatplain water has to absorb.


Water mist is now the standard in all new US Navy engine and machinery rooms, and is also quite common on cruise ships where massive generators power the ship.

Water mist depends on getting the fire while it's very small.
If the fire starts big, like a fuel leak and explosion ytour gonna cook your goose, right? And it a high pressure mist pipe breaks the high pressure stream could put an eye out, lol

Water mist is not dangerous to occupants provided they are not within 3 feet of the discharge heads (usually located along the overhead and spray like a commercial pressure washer in a broad fan), and provided there are no toxic components to the fire, being in the compartment during discharge and suppression are no more dangerous than standing deck watch in a dense fog.


We are starting to see water mist ashore now, the computer industry has seized on it, as has the cooking industry (both for its ability to rapidly contain and extinguish as well as its complete lack of harmful components). Many new Class K extinguishers are actually self contained water mist applicators.

The fire causes CO2 as a by-product of combustion, when CO2 mixes with water mist it makes carbolic acid that rusts metal?

It happens with the foam too.

[cfire3]

[QUOTE]Originally posted by cfire3
[B]

Originally posted by Fire304
The fire causes CO2 as a by-product of combustion, when CO2 mixes with water mist it makes carbolic acid that rusts metal?

It happens with the foam too.

I believe that's carbonic acid? dern! I hate I can't spell.

Well, it's an acid that causes metal to rust.

[Fire304]

The link below is to a US Navy test of an engine room water mist system aboard the USS Shadwell. The fire is a high pressure fuel line rupture, about the most violent and large fire a ship can expect to see not caused by ordinance.

http://chemistry.nrl.navy.mil/6180/6...s/JOHNFARL.MOV

It takes a little while for the fire to go out, but compaired to other fixed systems (halon or CO2) it is very fast and much safer for the crew.

The fire mains are not normally pressurized to full pressure (about 1000psi) so an accidental rupture would not lead to a hazardous discharge. Lower pressure mist systems also exist (about 400psi). Also, due to the extremely high pressure the system carries it is much more stoutly built that a normal sprinkler system (which just sink the ship when they break).

Carbonic acid, well you got me on that one, I suppose there must be some in the water, but compaired to the likes of dry chemical extinguishers it is extremely non corrosive, and I imagine that once the fire is out the mist suspended in the air probably washes a lot of the acid away.

[Resq14]

Originally posted by Fire304
As far as CAFS not being like water in that it does a better job of sealing the fire you're right, but if the fire is producing more heat than the water can absorb before reaching the seat of the fire it will evaporate and not put a dent in the fire. Resq14 found this out first hand last Thursday night as he tried to enter a structure that was really too far-gone for a single CAFS line. CAFS is amazing stuff but its no magic bullet, you still need water to put fire out, and it still works primarily by absorbing the heat. This is why you "paint the room" as you enter a burning structure with CAFS, all that foam stuck to the walls and ceiling will suck up heat and cool the room down reducing the volume of fire you face.

Even with a great response time for us (I think it was six minutes), we were well behind the eight ball on that one. Given our staffing and the extent of fire, I deemed it unsafe for our crew to progress further than the kitchen area. We had heavy fire in the front and rear portion of the residence, and were unable to advance in either direction. The fire was through the roof (2 story residence, fire on first floor) in a couple of minutes shortly after we backed out. Luckily all people had made it out prior to our arrival... they were very, very lucky. It seemed to light up like a blowtorch.

I'm starting to feel as though I prefer ditching the 1.75" line in favor of the 2.5"... I mean, with CAF, a CAF 2.5" line is easier to maneuver than a water 1.75" line, so there's really little excuse not to. I think that would've been able to achieve faster knock down. Also, better placement of the 2.5" CAF blitzfire line -- that thing ended up filling half the unburned portion of the house with bubbles. In reality, I would've liked to have had the blitzfire in the doorway with me.

[CaptainS]

quote:
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i dont know if this has been sugested yet or not, but how about using them to respond to car fires in parking garages?
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http://www.vrs-sales.com/Images/airport2.jpg

This is used by Albany International in the parking garages.

[FiftyOnePride]

We are currently working on a Quick Attack, we are doing so because we have a rather large size of our district that is up on a steep hill. We all know what large trucks have problems doing, and getting up a steep hill is one of them. This quick attack will get up there faster and get a head start before the larger trucks will be able to. It is basically going to be used for just what it is known for: a quick attack.