Thread: Offensive foam?
03-23-2000, 12:29 PM #1chiefjay4Firehouse.com Guest
Call me old-fashioned but I'm not sold on class A foam as an "effective" tool for bread and butter structure fires. At a well involved structure(commercial or residential) I feel that it is better to go with the theory, Big fire/Big water. I just cant see a 1 3/4" line flowing 95 gpm with class A foam being as effective as a 2 1/2 or 3" flowing 300 gpm. In the recent Fire Engineering, the article "little drops of water" part 2, stated that studies have shown that class A foam is barely more effective than plain water. What has your expierence with this?
03-23-2000, 01:12 PM #2KEAFirehouse.com Guest
>class A foam is barely more effective than plain water.>
I think you will find that most statements whether in an article or on this forum must first be disected to ensure the reader understands where you are coming from.
What I do know is that Class A foam will assist in the prevention of a rekindle because of the reduction of the water surface tension and does so much better than plain water.
Is it as good for initial fire Knock down?
I think it will be best for me to not voice my opinion on this one becasue no sooner than I do the battle will start
I have found that your question is best answered by those who are not in any way in the money stream from sales, whether its foam eductors, proportioners, nozzles, or foam. I'm not saying that those sources do not have good information. I'm only suggesting that a non-interested party would be far more objecitve with the topic.
Just my thoughts which were not intended to attack, degrade or promote any specific product or method of fire fighting
PS: It sucks to have to keep writing disclaimers
First Strike Technologies, Inc
03-23-2000, 10:23 PM #3Dalmatian90Firehouse.com Guest
Still go with the big GPMs for knocking down the flame...once the flames are gone though, Class A kicks butt since the flames don't come back.
We flow foam...unless it's the fire is so large all the water's effectively going up in steam. Then we knock down with plain water and switch to foam soon as the flaming fire has gone bye bye.
It may be antecdotal (sp?), but we are consistently seeing outbuilding fires like garages that we are handling with a single 1200 gallon tank through to extinguishment, that experience says it used to take us 3-4000 gallons to completely extinguish. Yeah, a little foam goes up in steam...but then the other foam keeps the fire from reigniting, helps to trap gases being given off by the hot fuels, and helps the water soak in and cool the fuels faster.
I don't think the foam helps the 'flames'...but once the water has knocked down the flames, the Class A foam keeps the materials from reigniting.
Little drops was a good article. And NYC does some great fire fighting. But there isn't neccesarily one best "set of tactics." Lloyd Laymen & fog attacks still work exceptionally well -- no, you don't use them with aggressive interior searches and VES like NYC does, cause you steam people. In rural areas, maximizing water effectiveness is often the bigger consideration -- and fog and foam works well.
03-24-2000, 06:29 PM #4ChiefDogFirehouse.com Guest
Just a quick bit of input. We have an A/B system on our new engine. When the foam system company representative came to give us a class, he said flow the Class A, but figure the needed fire flow the same as you always did before. We responded to a mutual aid barn fire a few weeks ago and the foam line worked well until we ran out of water. (tanker shuttle) we have not had a lot of experience yet, but we have see the fires once out, stay out with class A.
03-25-2000, 10:28 PM #5STBURNEFirehouse.com Guest
NIST recently did tests and found that knockdown time was the same when using CAFS, Class A or plain water. Overhaul was dramatically reduced when using class A however.
04-08-2000, 10:25 AM #6FirehoseFirehouse.com Guest
You stated that in the teest the knockdown time was the same, but did the test report the amount of water or water/foam that was used in each? The CAFS attack sould have used much less water.
04-10-2000, 10:01 AM #7chiefjay4Firehouse.com Guest
I guess the real question is are we jeopardizing ourselves in thinking that a 95gpm foam line is going to knockdown fire as well as a 300 gpm 2 1/2" handline? The 300 gpm handline knocks down three times more fire than the 95gpm. Does using class a foam compensate for the 205 gpm difference in the two lines? I havent seen it yet.
04-10-2000, 10:10 AM #8Dalmatian90Firehouse.com Guest
Maybe yes, maybe no.
Depends on the fire.
But in the end, run Class A through your 2.5" and it will still be more effective than plain water.
We run it standard on a 200gpm 1.75"
04-15-2000, 12:06 PM #9SYSIPHUSFirehouse.com Guest
My department is taking delivery of a new Engine/ Rescue unit and it will have class a foam piped in to all outputs. (adjustable @ valve) Have seen video on effectiveness and it absolutely makes your water go farther(@ 3x) but it also looks like less water means more heat.... interior crews observed that using class a foam knocked fire out as fast or faster than h2o and prevented rekindle but temps were noticeably hotter. Also looks like a great resource for wildland crews... more coverage w/ less h2o and appears to make on heck of a fireline.
Any comment from current class a system users would be greatly apprecieated.
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