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How does a wet cloth really help (scientifically) to survive an airplane crash?



 
 
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  #11  
Old May 16th 14, 05:33 AM posted to alt.home.repair,sci.electronics.design,rec.aviation.piloting
Ann Marie Brest
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Posts: 35
Default How does a wet cloth really help (scientifically) to survive anairplane crash?

On Fri, 16 May 2014 05:19:33 +0200, nestork wrote:

I agree with BobF; the wet cloth acts like a filter for both smoke
particles and fumes that would be soluble in water.


Until I read the referenced articles, I would also have believed that
filtering the smoke itself might have been a key safety issue.

But, we don't have any proof yet that smoke particles are anything
we care about from an inhalation standpoint during a cabin fire.

In fact, this detailed article about all the negative effects of
a fire mainly discuss "smoke density" as a visual impairment factor,
and not as a critical inhalent (see page 39 of 47):

"Compilation of Data on the Sublethal Effects of Fire Effluent"
http://fire.nist.gov/bfrlpubs/fire09/PDF/f09033.pdf

What we seem to care about is hydrogen cyanide, which is soluble
in water. So the web towel apparently absorbs the HCN before you do.

On page 19 of 47, there is a table of the results of experiments
of HCN gases on a variety of mammals, since they say only one
human study was ever done. However, it's hard for me to
extrapolate that table to what happens in a real cabin fire.

So, what we really need is the key datapoint:
a. What is the concentration of HCN in a typical aircraft fire?





  #12  
Old May 16th 14, 05:46 AM posted to alt.home.repair,sci.electronics.design,rec.aviation.piloting
Bob F
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Default How does a wet cloth really help (scientifically) to survive an airplane crash?

Ann Marie Brest wrote:
On Fri, 16 May 2014 05:19:33 +0200, nestork wrote:

I agree with BobF; the wet cloth acts like a filter for both smoke
particles and fumes that would be soluble in water.


Until I read the referenced articles, I would also have believed that
filtering the smoke itself might have been a key safety issue.

But, we don't have any proof yet that smoke particles are anything
we care about from an inhalation standpoint during a cabin fire.


A friend of mine was hospitalized for smole inhalation. They would come in
regularly and pound the hell out of his chest to break loose the crud in his
lungs so the body could try to eliminate it. Inhaled particulate matter can
without a doubt do significant damage.


  #13  
Old May 16th 14, 11:59 AM posted to alt.home.repair,sci.electronics.design,rec.aviation.piloting
Ann Marie Brest
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Posts: 35
Default How does a wet cloth really help (scientifically) to survive anairplane crash?

On Thu, 15 May 2014 21:46:22 -0700, Bob F wrote:

Inhaled particulate matter can without a doubt do significant damage.


I would tend to wish to agree, since we've all heard about firefighters
being treated for "smoke inhalation".

However, if particulates were a thread to life, why wouldn't the FAA
and the other cabin fire articles previously posted mention smoke
particles as anything more than an irritant?

Science, being what science is, doesn't always agree with our gut
feelings.

  #14  
Old May 16th 14, 12:24 PM posted to alt.home.repair,sci.electronics.design,rec.aviation.piloting
micky
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Default How does a wet cloth really help (scientifically) to survive an airplane crash?

On Thu, 15 May 2014 16:46:21 -0700, Ann Marie Brest
wrote:

I'm not sure WHERE to ask this, but, how does a wet cloth
work in an airplane crash anyway?


Why do they always boil water when a baby is coming?

Do babies drink coffee?

(on TV)

In step 3 at 45 seconds into this video shows it in use:
http://www.youtube.com/watch?v=RXaTt...etailpage#t=49

What's the wet cloth (scientifically) doing?


  #15  
Old May 16th 14, 12:34 PM posted to alt.home.repair,sci.electronics.design,rec.aviation.piloting
micky
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Posts: 18
Default How does a wet cloth really help (scientifically) to survive an airplane crash?

On Fri, 16 May 2014 03:26:21 +0000 (UTC), Ann Marie Brest
wrote:

On Thu, 15 May 2014 20:16:19 -0400, Frank wrote:

What's the wet cloth (scientifically) doing?

http://www.faa.gov/pilots/safety/pil.../Smoke_Web.pdf


That nicely summarized FAA article explains:
- Smoke is a complex of particulate matter, invisible combustion gases & vapors suspended in the fire atmosphere.
- Inhalation of toxic gases in smoke is the primary cause of fatalities
- Carbon monoxide & hydrogen cyanide are the principal toxic combustion gases
- Carbon monoxide combines with the hemoglobin in blood and interferes with the oxygen supply to tissues
- Hydrogen cyanide inhibits oxygen utilization at the cellular level.
- Carbon dioxide is a relatively innocuous fire gas, increases respiration rate causing an increase in the uptake of other combustion gases
- Irritant gases, such as hydrogen chloride and acrolein, are generated from burning wire insulation
- Generally, carbon dioxide levels increase while oxygen concentrations decrease during fires.

And then finally, the article suggests:
- Cloth held over the nose and mouth will provide protection from smoke particulates;
- If the cloth is wet, it will also absorb most of the water-soluble gases (i.e., hydrogen cyanide & hydrogen chloride).


Wow. That's good to have suggested. I certainly don't need any HCn or
HCl.

What's interesting is that the entire article doesn't discuss any dangers
of breathing smoke particulates, so, why it bothers to mention a dry cloth
is perplexing since we can safely assume that filtering out particulates is
merely a convenience,


How can we safely assume that? I'd assume the opposite.

and not a safety issue.


I think what you have is a 3-page** article where they decided to be
brief and not emphasize every problem. It's meant as advice and not a
scientific paper, so they've taken a short, clear-cut approach.

**Less than 3, given the pictures and the line spacing.

So, now we're left with the a WET cloth absorbing water-soluble gases.
Of the two water-soluble gases, only hydrogen cyanide was listed in
the article as being a safety issue (the other water-soluble gas was
merely an irritant).


Irritants irritate me. Anyhow, when HCl mixes with water it turns
into hydrocholoric acid, one of the stronger acids. I don't want that
in my lungs.


So, I guess we finally have the answer to "why the wet cloth?".

The WET CLOTH filters out (water soluble) hydrogen cyanide:
"Hydrogen cyanide poisoning signs & symptoms are weakness, dizziness, headache,
nausea, vomiting, coma, convulsions, & death. Death results from respiratory arrest.
Hydrogen cyanide gas acts rapidly. Symptoms & death can both occur quickly."


Yes, that's how they kill people in the gas chamber.
  #16  
Old May 16th 14, 12:48 PM posted to alt.home.repair,sci.electronics.design,rec.aviation.piloting
micky
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Posts: 18
Default How does a wet cloth really help (scientifically) to survive an airplane crash?

On Fri, 16 May 2014 04:33:21 +0000 (UTC), Ann Marie Brest
wrote:

On Fri, 16 May 2014 05:19:33 +0200, nestork wrote:

I agree with BobF; the wet cloth acts like a filter for both smoke
particles and fumes that would be soluble in water.


Until I read the referenced articles, I would also have believed that
filtering the smoke itself might have been a key safety issue.

But, we don't have any proof yet that smoke particles are anything
we care about from an inhalation standpoint during a cabin fire.


I think we're allowed to take judicial notice of everything else we've
learned in our lives.

It is frequenty reported that someone dies of smoke inhalation. That's
certainly something to care about. It may take longer than dying from
cynanide, but it's still bad.

I'm pretty sure the amount of cyanide varies widely from one airplane
fire to another, but there is no time to measure it.

In fact, this detailed article about all the negative effects of
a fire mainly discuss "smoke density" as a visual impairment factor,
and not as a critical inhalent (see page 39 of 47):

"Compilation of Data on the Sublethal Effects of Fire Effluent"
http://fire.nist.gov/bfrlpubs/fire09/PDF/f09033.pdf

What we seem to care about is hydrogen cyanide, which is soluble
in water. So the web towel apparently absorbs the HCN before you do.

On page 19 of 47, there is a table of the results of experiments
of HCN gases on a variety of mammals, since they say only one
human study was ever done. However, it's hard for me to
extrapolate that table to what happens in a real cabin fire.

So, what we really need is the key datapoint:
a. What is the concentration of HCN in a typical aircraft fire?


Who says there is a typical aircraft fire wrt HCN?

  #17  
Old May 16th 14, 12:58 PM posted to alt.home.repair,sci.electronics.design,rec.aviation.piloting
micky
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Posts: 18
Default How does a wet cloth really help (scientifically) to survive an airplane crash?

On Fri, 16 May 2014 04:00:28 +0000 (UTC), Ann Marie Brest
wrote:

On Fri, 16 May 2014 03:52:45 +0000, Ann Marie Brest wrote:

Armed with the new keywords "wet cloth hydrogen cyanide", I find more
on the toxicity of HCN over he


This flight safety PDF titled "Guarding the airways", is of interest:
http://flightsafety.org/download_fil...t06_p28-30.pdf

It mentions only that the "wet cloth" prevents irritation, which we're
not concerned with in this discussion.


Speak for yourself, John.
  #18  
Old May 16th 14, 01:50 PM posted to alt.home.repair,sci.electronics.design,rec.aviation.piloting
RobertMacy
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Posts: 7
Default How does a wet cloth really help (scientifically) to survive anairplane crash?

On Fri, 16 May 2014 04:24:46 -0700, micky wrote:

..snip....

Why do they always boil water when a baby is coming?

Do babies drink coffee?

(on TV)

...snip...


LOL! just popped out for a spot of tea?

However the heat from the hot water and towels dilates the cervix really
fast, but does increase the risk of infection.

Years ago, newspapers were used too, because they were steam press rolled
and sterilized, but not today.
  #19  
Old May 16th 14, 02:51 PM posted to alt.home.repair,sci.electronics.design,rec.aviation.piloting
Ann Marie Brest
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Posts: 35
Default How does a wet cloth really help (scientifically) to survive anairplane crash?

On Fri, 16 May 2014 07:34:02 -0400, micky wrote:

we can safely assume that filtering out particulates is
merely a convenience,


How can we safely assume that? I'd assume the opposite.


I also would have assumed the opposite, had I not read the
articles, which prove our assumptions invalid.

The other articles on cabin fires went into nice detail
as to how hydrogen cyanide acts as a cellular asphyxiant by
binding to mitochondrial cytochrome oxidase.

They explicitly stated that smoke particles are not
deadly in an airplane crash.

So, what you, or I, would have assumed about smoke itself
being deadly, is apparently wrong.

If you still think your (and my) initial assumption is right,
then what we need is an article about cabin fires which says
both that the smoke particles are deadly, and, that a wet
cloth reduces them.

Otherwise, we're just making non-scientific assumptions.

  #20  
Old May 16th 14, 03:00 PM posted to alt.home.repair,sci.electronics.design,rec.aviation.piloting
Ann Marie Brest
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Posts: 35
Default How does a wet cloth really help (scientifically) to survive anairplane crash?

On Fri, 16 May 2014 05:46:19 -0700, trader_4 wrote:

Just because someone writing a brief article doesn't specifically
mention something, doesn't constitute science.


Science isn't what you are I guess.
Science is what can be tested & proven.

I'd be glad if you can find a tested/proven article on airplane fires
which says that smoke particles, in and of themselves, constitute a
life-threatening danger in the time it takes to exit a burning airplane.

We found more than a half dozen sources, including scientific papers,
none of which said that the smoke particles were the immediate danger in
cabin fires - nor did we find anything that said a wet cloth filters them
out.

If we are to assume smoke particles are a life-threatening danger, we'd
have to find at least one scientific article that said that the
particulate matter itself could kill us in the time of a cabin fire.

Even then, we'd have to know that a wet towel would filter out those
particles.

I looked for papers backing up our (apparently erroneous) assumptions.
I can't find any.
 




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