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#1
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?? Chemistry of fire retardant??
I read in a recent Av Leak that the stuff fire-bombers drop is a
mixture of phosphate fertilizer and water. Can anyone tell me how the phosphate functions as a fire retardant? Is it ammonium phosphate, sodium phosphate, or what? Thanks. vince norris |
#2
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As my local firebomber base a block up the street told me, it is either an
ammonium nitrate or ammonium phosphate base with water, colorant, and something to make it "sticky". Nitrate or phosphate base is a function of the supplier of the goo. Don't get it on you, it is a bitch to wipe off. Jim vincent p. norris shared these priceless pearls of wisdom: -I read in a recent Av Leak that the stuff fire-bombers drop is a -mixture of phosphate fertilizer and water. Jim Weir (A&P/IA, CFI, & other good alphabet soup) VP Eng RST Pres. Cyberchapter EAA Tech. Counselor http://www.rst-engr.com |
#3
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As my local firebomber base a block up the street told me, it is either an
ammonium nitrate or ammonium phosphate base with water, colorant, and something to make it "sticky". Nitrate or phosphate base is a function of the supplier of the goo. Thanks, Jim, but what I meant by "function" is, what does the phosphate (or nitrate) DO? Isn't ammonium nitrate the stuff used to make car bombs? If so, why would it be dropped onto a fire? "Ammonium" is loaded with hydrogen and "-ate" means lots of oxygen. Neither would seem to ideal for quenching a fire. vince norris |
#4
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vincent p. norris wrote:
Thanks, Jim, but what I meant by "function" is, what does the phosphate (or nitrate) DO? Isn't ammonium nitrate the stuff used to make car bombs? If so, why would it be dropped onto a fire? "Ammonium" is loaded with hydrogen and "-ate" means lots of oxygen. Neither would seem to ideal for quenching a fire. vince norris Ammonium nitrate, by itself, is not a hazard. Growing up on a farm, I regularly hauled 8-ton loads of the stuff without any problems. Ammonium nitrate, when mixed with a fuel such as a hydrocarbon, is a great oxidizer. The combination is what makes the truck bombs (I don't know if they use it for car bombs) go boom. You also don't need terrorists to set it off - do a search of the Texas City disaster (or the Grand Camp - the ship that set it off) to see an industrial example. As for why it's used in arial drop flame retardants, I don't know if there's any fire related reasons. Maybe it helps modify the water's viscosity or something. However, I suspect that the fact that it's a good fertilizer is at least part of the equation. You don't want something that's toxic (save the trees from fire only to kill them slower with a poison), and this will help (a) the fire damaged trees in their recovery process, and (b) the re-vegetation process. Rich Lemert |
#5
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"vincent p. norris" wrote in message ... As my local firebomber base a block up the street told me, it is either an ammonium nitrate or ammonium phosphate base with water, colorant, and something to make it "sticky". Nitrate or phosphate base is a function of the supplier of the goo. Thanks, Jim, but what I meant by "function" is, what does the phosphate (or nitrate) DO? Phosphates make suds, like detergent in the 1960's. |
#6
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On 2003-11-16 16:21:37 -0800, vincent p. norris said
"Ammonium" is loaded with hydrogen and "-ate" means lots of oxygen Neither would seem to ideal for quenching a fire One would not think that applying a substance that was two-thirds hydrogen (great fuel) and one-third oxygen (oxidizer) to a fire would be helpful either, and yet somehow it is |
#7
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It does make a mess. A news reporter at a TV station I worked for had
one of our video redorders dumped on while covering a forest fire. It never worked again. -- Gene Seibel Hangar 131 - http://pad39a.com/gene/plane.html Because I fly, I envy no one. Nitrate or phosphate base is a function of the supplier of the goo. Don't get it on you, it is a bitch to wipe off. Jim vincent p. norris shared these priceless pearls of wisdom: -I read in a recent Av Leak that the stuff fire-bombers drop is a -mixture of phosphate fertilizer and water. Jim Weir (A&P/IA, CFI, & other good alphabet soup) VP Eng RST Pres. Cyberchapter EAA Tech. Counselor http://www.rst-engr.com |
#8
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One would not think that applying a substance that was two-thirds hydrogen (great fuel)
and one-third oxygen (oxidizer) to a fire would be helpful either, and yet somehow it is! Good point, Larry, but isn't water 1/9th hydrogen and 16/18ths oxygen? vince norris |
#10
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"Larry Fransson" wrote in message news:2003111700124016807%newsgroups@larryandjenny. net... On 2003-11-16 16:21:37 -0800, vincent p. norris said: "Ammonium" is loaded with hydrogen and "-ate" means lots of oxygen. Neither would seem to ideal for quenching a fire. One would not think that applying a substance that was two-thirds hydrogen (great fuel) and one-third oxygen (oxidizer) to a fire would be helpful either, and yet somehow it is! Hold it. The percent of the weight of the atoms in a molecule has nothing to do with the chemical properties of the molecule. These atoms are bound together. It is not a simple mixture. Another example: Salt is sodium and chlorine, but does not have the properties of either. |
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