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As I had a fire today the wind was blowing the fire and some smoke away from me , Yet the heat radiation you feel it no matter how much wind you have to your back .
So it made me wonder the word - heat radiation - Have i fooled myself as some others may have that keeping your back to the wind keeps toxins out of you path.
Can the toxins - radiate as heat does - and follow the path of heat ?
It would depend on the amount of force (energy) with which the toxin is released. For instance, if it's confined within a container or coating, as the heat builds to melt the container the toxin particles (atoms) will also expand. When the container is breached (and the toxins released with explosive force), the toxins will go in all directions - even against a wind of any speed. On the other hand, if the toxin is not confined (think of a carpet pad thrown on a fire), a slight wind will easily blow the toxin particles. That's not to say you can stand next to a burning carpet pad with a 5MPH wind, though.
In your illustration, the fire is the result of explosive release of energy (from wood?). The smoke is the result of energy released without confinement.
I wont burn some thing that will ultimately explode, But say you melt lead the wind is at you back you still feel the heat . wile toxins do flow with the wind do some also flow with the heat , Heat is the result of some thing reacting . But heat can also be the result of a toxic mix. SO is that heat from a nasty source a killer -
I guess radiation - like nuclear waste might have no wind boundary - if it was mixed with heat.
Any way its just a thought
There are three ways heat is generally transferred:
Conduction, Convection and Radiation
Conduction heat transfers occurs inside materials, like solid materials. The heat from the fire is passed from molecule to molecule through the material. The fire will generally follow the heat or sometimes the heat from conduction may cause a new fire to ignite elsewhere.
Convection heat transfer occurs only in liquids and gases (like air). The heat from the fire can heat the air, to a very hot temperature. Hot air will always rise, which draws air into the fire and feeds it. If you were for example standing in front of a fire that was raging, the hot air would rise so fast that it would suck air from lower levels, and feed the fire with more oxygen, flaming the fire. This air would then be coming from behind you, if you were facing the fire, but as it did, it could also be carrying some of the heat from the hot air that rose, and you might even feel some heat on your back, this heat would also cause the fire to burn even hotter.
Radiation heat transfer does not travel through a material like conduction nor does it flow through air or liquid currents like convection. It simply travels in rays similar to sunrays, in straight lines away from the fire. The heat from the rays can be absorbed by combustible materials which causes them to heat up and perhaps ignite. The main principle of radiation is: the closer the material is to the fire the more radiated heat it will receive.
Because any toxins, or smoke created is not heat, it will follow the direction of the wind. However, as with convection, if the heat is rising, it will draw the toxins upward, and if the fire is hot enough, and sucking in air that was displaced by the rising air, fast enough, it could cause a vortex effect, or act like a convection oven, specially in an enclosed space, so those same toxins that are being carried away by the wind, or hot air, could be now blowing on your back.
So far as toxins traveling on radiation, it doesn't. But it can travel on convection, and more likely than not does exactly that.
Scott
Let the physics lessons continue - anyone else?
an ruin the class? Not from me..LOL.
I swear..this forum is one of the best blessings to ever come my way.
Sirscrapalot - Not at the head of the class, but moving up to it!
Well what is clear to me now is , if the fire is strong and questionable in whats being burned , stay clear as the pull for air could pull toxins back towards the fire
That's right, and because many toxins tend to not be included in the smoke, you probably don't see them either.Quote:
Originally Posted by Copper Head
Places that carry an incineration license, and incinerate things that contain toxins, are required to scrub the exhaust so that the air expelled is cleaner than the air that went in.
If you want to see the wrong way to incinerate, watch this video. This is happening in several places in the world today.
http://www.youtube.com/watch?v=pr1zQrXM_7s
Pay special attention to what is said about the workers health.
Scott