TechStuff Classic: The Tech of Firefighting

technology of firefighting. This episode originally published on July two thousand eleven. I hope you guys enjoy Chris polettin myself going through the entirety of all tech associated with firefighting. As of enjoy, we wanted to talk about firefighting technology. We actually had a request come over Facebook for this and we wanted to. Uh. I thought that was a good request, you know, it's an interesting concept. We also, I think I got an email about it as well.

So we've had some some people enquire about the technology used in firefighting and there's a wide range of tech that we can talk about. Some of it is stuff that is based off of technology that's been around for more than a century and some of it is really like space age type stuff. So, um, I thought I thought i'd start with one of the most um iconic images when you think about firefighting, which of course, is

the fire engine or fire truck. So, uh, I actually live not too far from a fire station, and by not too far, I mean adjacent, and uh so I get to see fire trucks a lot. As it turns out, they're pretty cool things. And of course, you know, the main uh, I think the main feature on a fire truck has to be the water tank that that it holds, you know, and and the water tanks. Depending on the size of the truck, the water tank can be a

different size as well. Like you know, it's not unusual to find a fire truck that can hold a thousand gallons of water on its own. And of course that's important because there's no guarantee that wherever the fire is is going to be close to either a pool of water or a fire hydrant. Um So a fire truck has to be able to carry its own portable water supply. But having water on a truck is not enough. You have to have a way of getting that water out right,

So you would need some kind of pump. Yes, and UH and fire engines have pumps. They have an impeller water pumps, and an impeller water pump is a diesel powered pump. So it's got its own independent diesel engine and it has a rotor like device that's got some curved blades on it that spin in the water tank. Now, this actually slings the water around starts to move it in a circular fashion. It builds water pressure, and you relieve that water pressure by allowing the water to escape

through water lines also known as hoses. So they have to go through a valve and then it goes through the hose and at the whatever is burning thing, whatever is burning thing, Yeah, that's a technical term in the fire fighting trade. So the whatever is burning thing gets deluged with water. And there's actually some interesting controls on this. There's a series of controls. There's a pump panel that allows you to either manually control the pumps or some

of them are automated. They have like a Mastermind control system that actually does this automatically. But a typical pump panel will have levers on it that allow you to direct where the water is going to go through like which lines it's gonna go through, and of course that's all going to depend upon which lines have been connected to the truck. And there are lots of different kinds of water lines also. And again when I say water

lines there, those are essentially the fire hose is right. Yeah, These are a lot different from your garden variety hoses, Yes, because they can handle a whole lot more pressure and deliver a whole lot more water. As Jonathan was saying just a moment ago, you can't be certain that you're going to be right next to a fire hydrant where the fire is and the fire truck is going to

park on the street. Now, if the building, let's say it's the building is burning and it's away from the street, you've got to have enough water pressure to get to the fire itself. So the hoses are long, they're there, Uh, they've got some diameter on them, so you can really carry the a good amount of water and they've got

to be able to withstand a lot of pressure. Yeah, and they're also they tend to be treated for a mildew resistance as well, because one of the big problems with fire hoses before the mildew resistant um film was developed was that you had to dry them out after you use them, because otherwise you would have mildew develop. It would start to rot the hoses, and then the hoses would not be stable. You could have a hose rupture while you're trying to fight a fire because it's

been weakened by mildew. So uh, yeah, there's a lot of elements that go into creating these these hoses, and I've got a few different types I can talk about. Um, there's usually there's a booster line, which is only about an inch diameter, and it's usually used for small fires like uh, a minor fire inside a building or something like that, or a minor brush fire even. Um, then you've got the cross lay hoses. These are the main hoses.

These are like the workhorses of a fire engine. They're located below the pump panel and they can pump up to gallons of water per minute. Uh. They tend to be about two feet long and they've got a diameter of an inch and a half. So then you've got the preconnect lines. So, like I said, you know, you've got all these valves that are attached to the fire engine and they're on all the different sides of the fire engine, because you never know where you're gonna be

able to orient the engine in station to the fire. Normally, there is UH there are at least three lines that are pre connected when an engine rolls out of the station, so that way the fire fighters have a chance to immediately jump out of the truck and start fighting the fire without having to fuss with unloading hose, connecting it to the right valve, and then engaging the valve and

fighting the fire that way. So preconnect lines tend to be between an inch and a half to two inches in diameter, and they tend to be able to pump out around two fifty gallons of water per minute. UH. You've got hoses that are designed specifically to hook up to hydrants fire hydrants. Those are five inches in diameter, and a fire engine may carry up to a thousand feet of this hose, but it's in one foot segments. But there are also other shorter segments called curb jumper hoses.

So let's say that the building that you need to get about a hundred and fifty feet of hose UH to get to the fire at whatever location you're at, and you're hooking it up to a hydrant. You might not want to grab two lengths of the hydrant hose that's two feet and you know you don't only need a hundred and fifty um that that means you're gonna have an extra fifty feet of hose that you're gonna

have to maneuver around. Well, these curb jumper hose segments are typically in links between twenty ft lengths and fifty foot lengths, so that way it's easier just to grab a smaller section so that you have enough length of hose to get to where you're going without having excess. Then you've got your hose pack, which is a lighter hose, usually a smaller diameter, and this is what is used by firefighters if they have to go into a building and climb up levels. That has to be more portable.

You've got the ladder line. You know, most of these fire engines have a really long ladder that's on the back of them. Well, there's a there's a line that is part of that ladder. It's actually it's it's uh a direct connection to the ladder. It's actually built in. Yeah, it's built in, and there is a nozzle at the top of the ladder that can shoot out well, it's it's usually around three hundred gallons per minute, so it's a pretty powerful hose. And then you've got your deluge

gun or deck gun. That's what's mounted on the top of the pump panel. That's the one that you know that if you ever look at the fire engine, you see something that looks like a turret that's on the fire engine. That's the thing I'm talking about. All right, So we've been talking about hoses that can shoot out between gallons and three gallons of water. The day lug gun is no joke. We're talking a thousand gallons a minute. Yeah.

And you may say, well, if you've got a thousand gallons at the tank, does that mean that after a minute you've completely exhausted your water supply? And the answers, well, yeah, that's what you're if you were just using the water in the tank. But you can also hook up a a line to a a pool or acre pond and use that water to pump into the the various lines that you're using now. For that, they use a uh,

a strainer. It's a it's called a barrel strainer and that's what is used to filter out debris in ponds and pools and that kind of thing in order to be able to use that water to fight fires. Because of course, if you get debris caught in the line, then you've fouled the line. You are you know, in danger of losing the fight against the fire. But plus I imagine it would do quite a bit of costly damage to the equipment as well. Sure, yes, all of that is is uh, you know, an important thing to

remember when you are trying to to fight fires. And then there's also they tend to trucks tend to also carry foam, and there's different kinds of foam UH that are that's used for different types of fires. Usually a fire engine may only carry one type of film, especially if it's if it's in an area where UH fires are typically one type versus another. For example, a Class A foam is a kind of foam that's used to soak down an area after you've put out a fire

to prevent reignition. It's kind of a flame retardant. And then you've got like Class B foam that's the stuff that you use to fight flammable liquid fires. So like a car fire, you might want to use that because of the gasoline problem. So uh. And then the other part about fire engines, they are like mobile tool kits. So that's where all the fire fighting tools are are mounted in that and you may have some pretty low

tech stuff in there. I mean things like hooks and pikes that are used to tear down walls so that you can get at the places where the fire is to put the fire out. There's not a lot of tech there. But then you may have something like a chainsaw, you know chainsaws have that there's this there's some tech there that's just pretty simple tech. It's usually you know, a diesel engine that turns turns the chaine that you

can cut through stuff. But then there's also the uh a pretty famous tool I would say that you typically will find on a fire engine. Yeah, and I think I know where you're going with this since you just mentioned it a moment ago, but I think, uh, it's important to remember before while you're trying to guess what this famous tool is that firefighters, um these days often do a lot more than fighting fires. They're also responsible for,

uh doing some paramedic work. Um, you know, their first responders. So if someone is injured, they often call the the firefighters out um on the possibility that in addition to medical care, there might be um a fire related to it, and they might need to do both things. Like for example, as Jonathan was just pointing out, if you had a car wreck and uh, there's a possibility that gasoline might

spill and catch fire. So you have someone trapped in a car, Um, there's a possibility that there might be a fire. So who better to send than of fire writers who are trained in medical care. But the trick is getting them out of the car before something bad happened. Yes, and that's where that's where this uh, this tool comes in. It's called the Jaws of Life. And really the Jaws of Life is actually a series of tools, is not

a single tool. Um. There's a company that makes uh these tools, and the company is known as the Jaws of Life. Company actually has a full name. But it escapes my mind out tope of my head. But let's say, not that kind. You still haven't seen that movie, have you? I have not, we had someone asked us earlier. Um, no he has not seen Jaws. So Jaws of life, Jaws of Life. It's a hydraulic lee powered tool and by that we mean it uses a fluid to create

uh pressure and move heavy duty tool elements. And uh, let's I guess a little digression on hydraulic fluid would be a good idea here. So, hydraulic fluid is a fluid that is typically it's it's not compressible. It's incompressible, and by that, I mean you cannot squish it right right, Like most things that we think about, there's a little

squish factor. But hydraulic fluid is supposed to be incompressible and that means that the fluids that maximum density, you cannot cram them the the molecules of that fluid any tighter than it already is. So if the foot pressure on it, it's going to push. Yeah. Like if you have a a cylinder filled with hydraulic fluid and uh, you're you're trying to push a press, a piston into

the cylinder. At the point where everything is connected. You have a you know, the solid cylinder at one end, and then there the piston starts to push on it. There's a point at which the piston is not going to be able to push anymore because it is it is compressed as far as it can go and it will not compress any further. And you can use that to do work. Ye, and there are plenty of tools that do use this and the jaws of life to use a phosphate esther fluid. A lot of hydraulic fluid

systems will use an oil based fluid. As you can imagine, oil based fluids are not necessarily the best thing to have in firefighting equipment. Yeah, So phosphate esther is non flammable and non conductive. So the these hydraulic tools, the jaws of life, there are actually, like I said, a line of them, and the ones that are typically used in firefighting are cutters, which do what they sound like

they do. They are designed to cut through stuff, so, for example, the body of a car, because the hydraulic pressure is such that it will cause the the pinch, the the cutting edges of this device to close. It's such a force that metal just crumbles. And then you've got spreaders. Spreaders are kind of like, you know, imagine a pair of pliers and you open them. That's kind

of what spreaders are are doing. They fires in reverse. Yeah, you shove shove it into a gap, and then you start the hydraulic motor and or actually start the diesel motor, and that starts the hydraulic fluid. Uh. It pushes hydrug fluid through and makes it do work, and that's what causes the pincers to open and then you pop open whatever it is you were trying to open, or it tears apart one one or the other. And then hydraulic rams. So those are the three that are used the most

frequently in firefighting UH scenarios. So uh yeah, it's kind of We actually have an article on how the jaws of Life work and it goes into detail on each of those tools. So if you want to learn more about it, I do recommend that it's a very useful resource. And then also I guess I should mention what we're talking about hydraulics. The ladder on the fire trucks, those

are operated through hydraulics as well. There's a piston that is uh has got especially two different hoses connected to it, and the hydraulic fluid will either cause the letter to extend upward or to come back down. So those are that's your basic fire engine from from front to back. I mean there's There's a lot more we can talk about, but there's so much more firefighting technology. I didn't want

to just have this all be about fire engines. I hope you guys are enjoying this classic episode of tech stuff so far. We're going to take a quick break and thank our sponsor. So what do you want to talk about next? Well, most of what I got is sort of high tech, cutting edge type stuff. UM. One thing that that we should talk about, probably UM to some extent, or maybe we could cover it later if you want to go with all the high tech stuff now is the stuff that the firefight is actually wear

on their person themselves. Sure, yeah, let's talk about that. Because we just thought about fire engines, we should talk about the fire gear that the the firefighters are wearing. UM. This is they wear a lot, Yes, they do. UM. Of course they have to try to stay protected from um, the heat that's you know, it depends on what's burning, of course. Uh. Some some different types of materials will

burn hotter than other materials. UM. And you certainly don't want to have a firefighter go inside to rescue a person or to get at the source of a fire and have them uh pass out. From the heat or to to be overcome by heat and smoke inhalation. UM. So you have to you know, protect them externally and and make sure that they uh they can breathe, make sure that they could see and and you know, keep them as cool as possible. UM. One one jacket that

I read about that was really cool. It's actually called turnout gear UM, which is a basically the the heavy duty jacket that you might see them where. It's actually from a company called Viking UM. But it's got thermal

sensors built into the jacket itself. Now not now that this is sort of again sort of cutting edge, but this, uh, this different thing has sensors on the outside which change depending on There's an LED display UM on the jacket, and it will tell you at you know, at what point it is going to be a serious issue that he is going to be a serious he is going to be too hot for the suit's integrity. Yeah, and

and the firefighter will be a danger. Yeah. Well. The thing is that it monitors what's going on outside and inside. So by looking at the firefighter, you know, another firefighter could say, look, you know, he's in danger right now, being where he is and needs to get out of there because he may not be able to tell uh what's going on. He may be so focused on fighting the fire he may be ignoring a potentially dangerous situation

for himself in the heat of the moment. Yes, Apparently, when the outer temperature of where the fire is gets to about four two degrees fahrenheit um, the display, the LED display starts to flash, and it's six d sixty two degrees fahrenheit um, it will start flashing very fast. I can't imagine being in anything that hot. It's interesting because well, first of all, I got to know, you know,

paper burns at farehne. Yes, but I was gonna I was gonna say, you know, it's kind of interesting because if you look at the history of the heat resistant materials that firefighters have worn, the go to material for quite some time was called nomex, Yeah, which is a

fire resistant material. It's similar to nylon. It's kind of the same sort of a feel of nylon, but it can withstand really intense heat as a type of meta aramid fiber, which really you just need to know that's a heat resistance anthetic fiber that was developed in the lab and um it's actually kind of, uh, sort of a distant relative to kevlar um, which is a much more resilient, not necessarily heat resistant, but physically resilient material. So no mix was the standard for a really long time.

Back in the Houston Fire Department partnered with NASA to develop a Originally it was just to develop a new helmet for firefighters, but then eventually, through this partnership, NASA suggested that perhaps they could completely redesign the fire fighter suit, and they started to create suits that would circulate liquids within the suits lining in order to remove heat so that it would protect the firefighter longer in intense heat conditions.

Because before that point, the Houston firefighters were really only rated to go into areas that were three degrees fahrenheit or cooler. Afterward, they could go into areas that were

five hundred degrees fahrenheight or cooler. And now you're talking about a system where you know, it warns you at four two, which is right around that you know, that five hundred degree range that was just talking about, but it goes all the way up to six, suggesting that this material is even more resilient than the stuff that

was made back in NASA. One of the other cool things that they added in that that same project where they were redesigning the helmet, they created an improved two way radio link ups in the helmets themselves, and they also created a infrared camera system so that you can so that the firefighter could switch to a thermal view and see hot spots in the house and also help firefighters identify if any victims were UH in the area, so that they you know, they could see the heat

from a person, then they would know that they needed to UH to. You know, you might not be able to see because the smoke might be so thick. And actually, infrared cameras play a really big role in firefighting technology across the board, not just in personal firefighter gear, but for example, a helicopter flying over a wildfire might be equipped.

In fact, most of them are equipped with infrared cameras and infrared lenses so that they can so the pilot or the watch's not really the pilot, but a firefighter aboard the helicopter can look through and see the hot spots and see the flames even if the smoke is so thick that you couldn't see anything, you know, just through a regular view to the ground. I'm sorry that was a big digression, but you were going back to

the cutting edge gear. Yeah. Actually, uh we we can keep going with that because I was reading an article on Popular Mechanics about some of the different cutting edge firefighting tools UM some firefighters for for things like, uh, scenarios like that, you're talking about a fire in the in the wilderness, UM are using unmanned aircraft. Yeah, it's a monitor areas and using UM infrared technology to identify places where uh, you know, you can really concentrate on

on fighting the fire. The thing is, UM, we have really talked about yet. It's on our list of things to do. But these unmanned aerial vehicles can stay in the air far longer than UH piloted human piloted aircraft. They can stay in the air for well. The ones that they use in them the military can use stay in the air for almost a day I think maybe

even longer. And they can fly through thick smoke that a pilot, depending on the type of aircraft, may not be able to fly through because you know, smaller aircraft, which is often what's being used to fight fires, uses a lot of line of sight UH navigational UH techniques rather than flying by instruments. So if you're gonna fly into an area that's that's got to really low visibility, that's very dangerous for the pilot. So it's much more

safe to use a pilotless drone. I mean you've got the person who's controlling it is controlling it from a a workstation as opposed to in a cockpit. Um. Yeah, did you come across the the I'm probably gonna butcher this name because my Native American languages are non existent

uh Icona, Yes, I did? I k h A in A. Yeah, it's a it's a predator be drone that NASA has UM that is specifically designed to to fly through areas that are either threatened by wildfires, are actually currently in experiencing wildfire, And it's got a lot of sensors on it that allow it to UH to detect exactly the

intensity and location of a fire to help firefighting strategies. Yeah, you don't typically think of NASA as being a firefighting agency, but they have been partnering with in the United States Forest Service in developing this technology and working on ways to keep forest fires from getting out of control UM. There's also moderate resolution imaging spector radiometer or modus UM, and basically that's a there are two satellites in orbit

around the Earth UM. They're using instrumentation that can detect electromagnetic radiation UM. And so basically, over the course of a day or two, UH motus is keeping an eye on on the Earth to look for radiation that would

indicate where where there's smoke and there's fire UM. And you can look at things like uh you can sort of overlay this with areas of population density, areas of vegetation, things that might UM indicate that there is a serious imminent danger of say a fire spreading if it's going to get to a grassland or you know, coming close enough to an area of population density where you need

to start evacuating people to keep them out of the way. UM. You know it's using satellite imaging is a very sophisticated way of fighting fires because you can get uh uh feel pardon the well worn expression, and a big picture of view of what's really going on. And in a fire of a size like that, of course, that's a much bigger fire than the ones we were starting out the podcast talking about Yeah. Yeah, I mean NASA has done a lot of work with satellites and fire detection.

I mean back at two thousand three, that's when they started to to develop a software that would scan for for fires and then uh, if a fire was detected, then NASA could direct a more powerful satellite to look at that area specifically. There's also the lands at seven satellite, which is designed to detect moisture levels and and forceded areas to determine likely spots where wildfires could form because of course, the wildfire is more likely to form in

a very dry area. Those conditions are our prime for a wildfire because you've got a lot of dry fuel and then if there's any wind then that's going to spread that fire around very quickly in that area. So that's that's or the purpose of lance at seven. It's just a kind of identify potential spots where a wildfire could develop with the right conditions. I mean, obviously you're gonna have to have something that's gonna spark the fire. Guys, I know this is a super hot topic right now.

We're gonna take a quick break and thank our sponsor. Also write about in um in popular mechanics about some software developed by the Canadian inter Agency Forest Fire Center UM called Prometheus. Yeah, the Bringer of Fire, Yes, exactly. In this case, it's actually designed to identify the likelihood of fire before it actually starts to burn. Very very cool idea basically using it's sort of like if you

think about it's sort of like a meteorological models. They're taking environmental factors into account, um ecological factors and and looking at those to get an idea of the likelihood of a forest fire starting and spreading, so they can kind of keep an eye on on that before it

even really at conflagration starts. Uh. Speaking of meteorological equipment, actually a lot of well fire stations tend to have a lot of meteorological equipment actually on the station, mounted on the station because you know, firefighters need to know this information. If if humidity is high, then they know that the fire is going to spread more slowly than if it were a dry day. Um. They need to know what the wind speed and direction is because that's

going to affect how they attack a fire. It also will affect how a fire might spread. So a lot of weather equipment is uh, you know you'll find a lot of weather equipment attached to your typical fire station, and you know that way they have the most up to date information available before they go out to uh to fight a fire. Um, you want to hear about a couple other cutting edge tools. I ran into. The two I've got that I wanted to talk about are

kind of future potential applications. Yes, did you run across the controlled impact rescue impact rescue tool? Uh? This is something if you've heard of the company at raytheon, you probably associate them with defense technology and microwave offense. UM, but among other things, many many other things. Uh, but

the this is sort of high end weapons grade firefighting technology. UM. If you're looking at a concrete wall and you need to get inside because there's a fire on the other side, and you've you've absolutely got to do this getting through, that's going to take you a long time using conventional tools. So, UM, this is a prototypical tool, or at least it was in at the time. This the article I'm used as

as sources written. Um, it uses blank ammunition cartridges and fires those into the wall to make the wall crumble just from the shock waves of firing the blanks. Into the wall. UM. The equipment waste about a hundred pounds, which means that you've got to have to firefighters carrying the equipment up there. But it doesn't require any electricity.

You know, it's it's essentially a gun, um. But you can use the device to basically pound your way through a thick concrete wall a lot faster than you could if you were trying to use a jackhammer or electric saw. I can easily see a fictionalized version of that weapon being used in video games from here on out. UM. And then, uh, did you read anything about using electricity to fight fires? Yes? Yes, Uh, that is one of the ones that I wanted to talk about. Over in

Harvard University, some researchers discovered something interesting. They found that you know, it's been known that that flames will react

to an electric field for quite some time. But what the the researchers at Harvard University found was that by using a variable electric field, which means they were using alternating current uh to go to travel across a wire, UM, they would create this variable electric field, they would direct it toward a flame, and they discovered that it would snuff a flame out and the the What was at work here was that the the variable electric field was

actually exerting force un charged particles within the flame itself, probably probably carbon particles from what I read. Yeah, and it and it's pushing those particles away from the fuel source. So it's literally pushing the flame off the fuel, so it snuffs it out, you know, in the fuel. The rest of the fuel remains unburned. But this is, um, this is just a small kind of laboratory setting, uh that you know, it's not a it's not a like

a field test. And moreover, this sort of application is really going to be useful for small, confined in spaces. So any place where a fire might break out in a tiny area like let's say it's a compartment in a ship like a navy vessel. It's down below decks and you have a fire breakout, well, this could be a good way to contain that fire, to snuff out

that fire quickly. Um. And you you know that you've got to again a pretty confined space in that when you're working with that, if you're talking about something like a house fire or a wildfire, this approach is not necessarily going to be very effective. So it's not like, we can just make a massive electric wand pointed at California and say you're done, no more fires for you. It's not gonna happen that way. Plus a lot of people are gonna be mad that their tiki torches just

went out. Nice, thank you. But yeah, you could use it to uh um to escape a fire if you were in a situation that that's a good point. Yeah, you can make a lane um. Yeah. The article i read on it basically said if you were a firefire inside of building, and there were a wall of fire in front of you, you could you know, create an escape route for yourself by using this on a on a small area enough to to get through and to

the other side. Sercially, yeah, you wouldn't be able to necessarily put out the fire, but you could at least create an avenue to get out of that situation. Or it could be used as a sort of augment a sprinkler system um mounted on the ceiling, so that you could, you know, use that on a small area within a building, which would be kind of interesting. I don't know. It would sort of depend on the type of equipment the that you were working with, and if you had something

like electronic equipment. Yeah, and we go that you're generating electronic electric field. You're not shooting lightning out the end of something. So that's something to remember. It's not like you're blasting stuff of lightning and then the fire goes out. That's that's that'd be cool, but it's not what's happening. Did you read about using acoustic waves to put out flames? No?

I didn't. All right, So this is another one of those things where it's an idea that could have potential but uh, but it's going to take some more tests and some more uh experimentation to really find out if it's if it's a worthwhile pursuit. The idea is that you use acoustic waves, so sound to snuff out flames.

And there were some early experiments done mostly by students, really like science students in college level and even lower where they would use a really sort of a low frequency sound like we're talking about in the forty hurts frequency range and boost it up really powerfully and you and when brought close to a flame, the flame would go out. And the idea is that we might be able to use this kind of technology in areas where

there's UH zero gravity, for example, a space station. So if a fire broke out in a space station that would be at astrophic. It's also really unusual because you know, flames behave in our in a really odd way in outer space, and it's because of the lack of gravity. So instead of a you know, a tear dropped shaped flame that you might see one on a candle here on Earth, in space, it's round because there's no up and there's no down. There's no you know, the heat

doesn't go up. The heat just stays where it is and it gets hotter and hotter and hotter, and it doesn't But yeah, heat doesn't travel, it doesn't go outward. There's no it's which is kind of hard to get your head around. But uh, it's also in the outer space. In in a place like the space station, using water is not terribly effective either. Um, it doesn't behave the same way in a zero G environment. Using foam is really messy and dangerous potentially dangerous as well. So that's

why they're looking at various alternatives to using a physical substance. Um, what really the basis of of fighting fire is up to this point has been chemical. You're you're you're aiming at the fuel and you're trying to put out the flame that way. Um, this is more of a physical way of fighting fire. You're physically finding a way to remove the flame from the fuel and thus snuff it out, And both the electric field and the acoustic wave methods

fall into that category. Well, that wraps up another classic episode of tech Stuff. I hope you guys enjoyed listening to that one. If you have any suggestions for future episodes of tech stuff, brand new topics that I haven't covered before, send me an email. The address is tech stuff at how stuff works dot com, or draw me a line on Facebook or Twitter. The handle at both of those is text stuff H s W. Don't forget. You can find hot, hot hot merchandise over at t

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