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Author Topic: Halotron Fire Extinguishers  (Read 1752 times)
KB4QAA
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Posts: 2382




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« Reply #15 on: November 02, 2007, 08:00:40 AM »

- I stated "Halotron I is not inherently toxic".   Perhaps I should have more correctly said "Halotron I is not immediately deadly".    Per the product literature, Halotron I requires four (4) hours of exposure at +3% concentration to reach LC50 (lethal concentration at which 50% may die), due to heart arrythmia effects.   A five minute exposure to fight a fire amounts to only 2% of the time required to reach lethal exposure.  Sounds reasonable to me.

- The FAA has never banned Halon fire extinguishers.  You can check the AD's (Airworthiness Directives) for yourself.  I'm sorry your trusted IA mislead you.:   http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/MainFrame?OpenFrameSet    

- Aviation Halon fire extinguishers are are still commercially available from companies like H3R Aviation, Safecraft and carried by Aircraft Spruce and Supply:   http://www.aircraftspruce.com/catalog/pspages/safecraftext.php      

- The Specific Weight of air at standard atmospheric conditions is:  7.492 10^-2 lb/ft^3 at 70F

- Check out the Halotron I product information:   http://www.halotron-inc.com/halotron1.php

- I apologize if my previous bluntness offended anyone.
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KB4QAA
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Posts: 2382




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« Reply #16 on: November 02, 2007, 10:00:45 AM »

-  This study for NASA exposed human subjects to Halon 1301 for 24 hours without significant ill effects.  Halon 1301 is the fire fighting system installed on the space shuttle. http://toxsci.oxfordjournals.org/cgi/content/abstract/20/2/231

- Halon & Halotron I interefere with the chemical reaction of an open flame and do not react the same way within the human body.

- Anaesthetic effect is NOT due to oxygen deprivation.  If that were the case, surgeons before the time of the Greeks would have merely clamped off the jugular arteries to some degree and be able to operate with the patient partially awake.  Chemical anaesthetics would never have been developed after the Civil War.   Anaesthetics are generally thought to work at the nerve and subcellular level and involve complex chemical interactions not involving circulatory oxygen levels.   Despite decades of use, modern medicine often has a poor understanding of their exact method of action.

- Regarding why simply breathing Halotron I or Halon does NOT cause suffocation:   The action of these fire inhibitors is believed to result from the chemicals binding with free hydrogen, H-, and hydroxyl, OH+ groups, preventing continued combustion.    In the human body oxygen, O2, binds to the Hemoglobin molecule at the Iron, Fe++ site.   Basic high school chemistry shows that the valences are opposite and unequal between the two processes, therefore the clean fire fighting agents cannot suffocate one by chemical reaction.
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W5ONV
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« Reply #17 on: November 02, 2007, 03:25:48 PM »

KB4QAA,
 Thanks for the info,sounds like you know what you are talking about relating to Halon.  73, Jim
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PD2R
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Posts: 131




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« Reply #18 on: November 02, 2007, 07:02:37 PM »

I don't want to offend anybody but if you don't know what it is that you are talking about, please keep yourself from replying to this post. This forum is called a Elmers forum a reason.
As a new bee HAM I spend a lot of time on this forum reading all the subjects that I find interesting. I do not reply to any of the technical questions because most of the time I don't have a clue.
This topic however is different, this is right up my alley.
As an instructor at the Royal Netherlands Air Force Fire and Rescue Training Center I should know a thing or two about fire extinguishers.
Halon gasses are one of the best, if not THE best agents to extinguish fires. It has a negative catalytic effect on the fire and you don't need much of it to kill a fire. Small amounts of it posses little danger for your health and it does not do any further damage to whatever you try to extinguish.
That is why it is especially used in airplanes!

CO2 is a liquefied gas (just as halon) and it works by displacing oxygen. When such a liquid wants to change into a gas it needs heat to do so which it will derive from the surrounding air. That sounds good but it is a well known fact that a gases are very good insulators so they aren't really capable of lowering the core temperature of the fire. That isn't a problem with liquid fuel of gas fires, but with solid flammable materials it doesn't do much.
If you want to compare halon with CO2, halon is far better and therefore you need much less of it.
So, why doesn't everybody use Halon? Answer: It burns a hole in the ozone layer. That is why the use of halon is strictly regulated. We, as a fire and rescue service aren't even aloud to use it anymore (since 2002/2003). In fact, one of the few places where you can still find halon is in an aircraft. For almost every other purpose it has been banned.

What would I recommend for your shack: use a fire blanket. They are cheap, reusable, you can use them on a person and do not have to be serviced every year or so. If you really want to have a extinguisher, Halotron is good. It isn't as good as Halon but it doesn't wreck the ozone layer.
CO2 is also a very fine extinguisher for your shack but keep in mind that it works by displacing oxygen and that you need oxygen to stay alive as well. If you ventilate the room after you have extinguished the fire you should be fine.

What you shouldn't use: Dry chemical fire extinguishers. They work in the same way as halon does but it can cause extensive damage to you sensitive electronic equipment.

Finally, everyone should have one or more smoke detectors in his of her house. They may not protect your shack, but they could make the difference between life and death for you and your family.

73, Maarten
PD2R

P.s. I could go on about this subject and explain what a flashover or a backdraft is and how they occur but this still is a HAM radio forum so I won't ;-)
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