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

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

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

If nobody can show *any* reasonable evidence of what they're
supposing (i.e., guessing), what does *that* constitute?

On Fri, 16 May 2014 10:48:00 -0700 (PDT), trader_4 wrote:

Just because some basic guides on what to do in a fire,
don't specifically say something one way or the other,
you can't "safely assume" anything.
Yet you keep doing it.

You appear to have completely misread my actions, so I must
not have been clear enough in the purpose of this thread.

I apologize.

The question is one of survivability science.

It's about how a wet cloth helps someone *survive* during
the time it takes to get out of an airplane during a cabin
fire.

I started with zero assumptions.

The only assumptions "I" have made during this thread are
those that are stated in the aforementioned flight safety
references.

Other people made a whole bunch of assumptions, some of
which are supported in the references, but some are not
supported in *any* of the references.

If someone makes a supposition that is actually supported
by a reasonable reference that they provide, I'd be *glad*
to listen to their assumption and to read their reference!

That's the whole reason for asking the question in the
first place!

On Fri, 16 May 2014 07:23:47 -0700, Bob F wrote:

Wood, cellulose, cotton, silk, wool, etc., were bad decades ago,
but they were nowhere near as toxic as the chemically-manufactured
materials of today.

This article lumps all the toxic gases and particulates plus
the irritant gases into a single word "smoke", but it also
lists at what temperature some of these synthetics melt at:
http://www.survival-expert.com/aircrash.html

Nylon melts at 265°C (510°F) and burns at 485°C (905°F).
Polyester melts at 254°C (490°F) and burns at 488°C (910°F).

On 17/05/14 05:01, wrote:

Something to keep the father occupied and out of the way.


Bingo

On 17/05/14 05:00, Frank wrote:

If I'm in a burning about to crash plane, I think the last thing I would
worry about would be the smoke


As the airspeed would 'fan' the fires it would also take all the smoke
away for the few seconds you'd have to live

On 5/16/2014 12:42 PM, Ann Marie Brest wrote:
On Fri, 16 May 2014 08:05:39 -0700, RobertMacy wrote:

For certain, a wet cloth over the head
would help shield. To see the potential shielding just envision sticking
your head into a barbecue pit with, and without, the wet towel. The air
into your lungs gets cooled so won't sear as much and at least your
corneas should remain intact.

I used to think that jumping up into the air when an elevator
crashes to the ground, would stop me from crashing along with
it. It's not supported by the facts.

Neither is the theory that the wet cloth is there to protect
us from the heat of the air during a cabin fire supported by
*any* of the flight-safety references we have so far been able
to find.

Sounds good. I'd believe it myself, if I was just guessing.

But, there's *nothing* in those flight-safety PDFs that says
that the wet cloth protects against heat in a cabin fire.

Now that's not to say that a cabin fire isn't *hot*.
For example, this previously listed PDF shows the temperatures
that can be reached in the cabin during a fuel-fed fire are
extremely *HOT!*.

http://wenku.baidu.com/view/8abb4621...fcc220e6f.html
"In an aircraft accident that involves a fuel-fed fire, cabin air
temperatures could be expected to reach 662 degrees F (350 degrees C)
and higher. During inhalation, the air temperature might be
reduced to between 360 degrees F and 302 degrees F
(182 degrees C and 150 degrees C [respectively]) by the time
the air reached the larynx"

That article mentions that the wet cloth might filter out
smoke particles (which don't seem to be an immediate danger),
but it doesn't even hint at that wet cloth cooling down the
air.

So, unless someone comes up with a good reference, I think we
can safely say that the *assumption* that the wet cloth is
there to cool down the air breathed in a cabin fire is a false
assumption (however good it seems to "sound" to most of us).


Well, as soon as (or maybe before) the water in the towel
evaporates/boils/steams, it will become impossible to survive.

On 5/16/2014 12:00 PM, Frank wrote:
On 5/15/2014 11:26 PM, 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).

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, and not a safety issue.

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).

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."


If I'm in a burning about to crash plane, I think the last thing I would
worry about would be the smoke

If you are the driver and can't see through the smoke, would you worry
about the smoke then or relax and resign yourself to your fate?

On 17/05/14 08:28, John S wrote:
On 5/16/2014 12:00 PM, Frank wrote:
On 5/15/2014 11:26 PM, 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).

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, and not a safety issue.

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).

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."


If I'm in a burning about to crash plane, I think the last thing I would
worry about would be the smoke

If you are the driver and can't see through the smoke, would you worry
about the smoke then or relax and resign yourself to your fate?

I believe you meant to type 'pilot' and I'd be doing everything within
my power to fly the aircraft and survive

On Fri, 16 May 2014 03:30:48 +0000 (UTC), Ann Marie Brest
wrote:

On Thu, 15 May 2014 18:22:53 -0700, Bob F wrote:

My guess would be that the wet cloth catches many of the smoke particles,
and the water will cool the air you inhale.

Based on the one referenced FAA article, the dry cloth does nothing for
safety, but a wet cloth reduces the water-soluble hydrogen cyanide gases.

In WWI, early in the gas warfare stage before there were gas masks,
soldiers wet cloth with urine, which apparently absorbed chlorine and
phosgene and stuff pretty well. It's better than dying, I suppose.


--

John Larkin Highland Technology, Inc

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

On Fri, 16 May 2014 15:25:35 -0500, John S wrote:

Well, as soon as (or maybe before) the water in the towel
evaporates/boils/steams, it will become impossible to survive.

It seems, from the references, that 90 seconds is the golden
time period you need to get *out* of the burning aircraft.

So, all it has to do is stay wet for a few minutes to do
the intended job of helping to dissolve HCN gases.