Explosive Decompression - Emergency Breathing Techniques

[justanotherflyer]

In the absence of sufficient cabin altitude, and failure of supplemental oxygen, is there any case to be made for emergency breathing techniques?

Perhaps adapting those used by mountaineers ("grunt breathing", etc. See this article (http://www.immunesupport.com/library/showarticle.cfm/ID/3214/e/1/T/CFIDS_FM/), or this one (http://www.appearfirst.com/recreation/sports_6.html) for instance.

Is any such training given in current civil or military operations

[tall and tasty]

Emergency Breathing Techniques

best one is find an available young man and make sure you make a tight seal around his lips and help him breath

what a way to go if you are going to draw a last breathe

TnT ;) :p ;)

[justanotherflyer]

How very amusing. Some serious replies would also be welcome.

Note to moderator: didn't intend this for Jet Blast, perhaps you could move it to an appropriate forum.

[TheOddOne]

If you're at a cabin altitude of FL250 or above, then all the breathing techniques in the world aren't going to prevent you losing consciousness in around 30 seconds. The only training for this situation is to get on to an oxygen supply within that 30 secs. The other part of the training is to ensure that you have that supply available, before embarking on the flight.

Cheers,
The Odd One

[SASless]

Well's...let's considere it is minus 50 degrees or there about...the air is as about as thin as my wallet....and the airplane remains at cruise altitude until it runs out of fuel....

Just what are you going to grunt breathe at 34,000 feet?:uhoh:

[TheOddOne]

Just before this gets moved to a more sensible forum, TnT has a point, 'cept of course that I'd MUCH prefer to change the genders around in my case, or it would be definitely NOT the way I'd like to go!!!!!

The Odd One

ps why do these ladies always seek after a young chap to draw their last breath with? Who's going to look after us old'uns??

Oh, I see, no-one...

[Ozzy]

I guess holding one's breath for a minute while you liberate an oxygen supply is out of the question

Ozzy

[waldopepper42]

I think I read somewhere (senility kicking in chaps, help me out) that Everest has been conquered without the use of oxygen. The trick, I believe was to very slowly acclimatise yourself to the high altitude by spending time at several increasingly higher levels.

Therefore, you have the answer: spend 6 months gradually ascending the Himalayas before each flight! :E :E

[tony draper]

A sudden lung full of even very thin air at -40 degree can't do much good either.
:uhoh:

[Darth Nigel]

Been reading Jon Krakauer's book "Into Thin Air" about a major problem on an Everest expedition.

As I recall, even after acclimitization to the altitude, above some level (26,000' I think), your body starts consuming itself because of the low oxygen levels -- you start losing fat and muscle tissue and other stuff. Sounds like a whole bunch of no-fun.

Not to be morbid, but a sudden decompression might not be a bad way to go out -- a moment or two of panic, a realization that all the pretty women are now attached to men other than yourself, and then lights out.

Then you wake up in the line at the Pearly Gates, and St. Peter says, "go away, mate, your name is on Draper's list"

[Onan the Clumsy]

You should carry a turky roasting bag with you on each flight.

This is by far the most effective and cheapest flight safety and egress equipment you can possibly carry.

[Rupert S]

And let's not even talking about trying to hold your breath before the decompression has completed. Sounds messy.

[Solid Rust Twotter]

You could always hold your breath if you have advance warning.




...Of course, this may lead to a Mr Creosote impression you certainly won't enjoy.:E



You with the penguin.....! Yes, you!....... Why are you stalking me?:E :ok:

[White Bear]

From a currant thread in the Questions Forum:

Oxygen vs Altitude
My question relates to the emergency oxygen facility of an airliner (or any high altitude pressurised aircraft). My understanding so far, is that as altitude increases, pressure reduces, but the level of oxygen in the air remains the same. Therefore, because of the reduction in pressure, our bodies cannot absorb oxygen very well and thus we can get hypoxia.

So, when the oxygen masks are deployed (in an emergency) with a supply of oxygen, how can this help us to breathe if the outside pressure is still too low? Does it have something to do with the pressure of the oxygen chamber which goes over your mouth?

Thanks pruners,

Maz


But:
If oxygen remains at the same level (20%) as altitude increases then why do I have to lean my piston engine to correct the air fuel ratio? I mean as altitude increases, the engine breathes less air, because it is less dense, and as the carburetor dispenses fuel based upon the mass of airflow, then because the mass flow is lower it will dispense less fuel, automatically correcting the air fuel ratio.
Or am I being very dense myself…
Regards,
White Bear.

Oxygen vs Altitude

[mystic_meg]

In the absence of sufficient cabin altitude, and failure of supplemental oxygen, is there any case to be made for emergency breathing techniques?

.....and exactly what are you going to breathe, pray tell?

...as someone who has (deliberately) come off oxygen at 25,000 cabin altitude in an aircraft - momentarily - let me tell you that the first thing you will do is cough uncontrollably like a 200 a day addict....

....emergency breathing techniques? Don't think so....

[innuendo]

Drapes,
"A sudden lung full of even very thin air at -40 degree can't do much good either."
I'd agree about the "Thin" but the -40, although bracing, actualy seems not to have too much permanent effect as any one who has spent time in the far frozen North of Canada can tell you, through experience. Just don't freeze any of your bits.

[SyllogismCheck]

[Sorry, off topic post.]

White Bear,

There are many other variables caused by changes in air density with altitude, and hence its compressibility and other factors in the inlet tract, but, in very rough terms, the carburetor does not so much read air mass as air velocity.
The pressure drop this velocity creates as it passes through a venturi in the inlet tract serves to siphon fuel from the float chamber into the inlet air stream.
Obviously the element in the air required in combustion is oxygen, which decreases in abundance, for any given volume of air through that signal venturi, with altitude.
The volume of air, more a less, being a constant of the pumping efficiency of the engine maintains a more linear siphon effect on the fuel than is required resulting in the mixture becoming over rich, hence you lean the mixture to compensate.

By no means the best example, as it's more concerned with design inefficiencies than principle, but take a look here (http://www.aeronautics.ws/blunder5.html) (some way down the page) for a little more insight. (Sorry, only made a very brief search for an example and this certainly isn't the best, previous or subsequent pages may be more relevant possibly.)

Edit to add: Here's a better link. (http://www.aerotraining.com/reference/AC%2061-23C_Chapter_2.pdf) Scroll down a good way to a section sub-headed 'Mixture Control'.

[LEM]

Chatting with a colleague today he said your blood will start to boil at 34000ft, so even if you wear an oxygen mask you won't survive the sudden decompression.
I told him this is not true, at worst you'll feel some bends...

Anybody able to confirm?

[LEM]

Yeah... I told him that was BS, but his point was that the rapidity of the pressure loss makes your blood boil... :rolleyes:

[Smoketoomuch]

"...he said your blood will start to boil at 34000ft"

From memory, I think it's 72,000 ft. Well, water boils at 37C at that height.

[GlueBall]

I heard that blood boils at 67,000' at ISA....can any of you astronauts confirm this...?

[Milt]

At or just above 55,000 ft your blood begins to boil so take care!

Pressure suit an absolute essential - otherwise prepare to scatter the ashes.

[Sheep Guts]

I suppose rather than a lung full of -40 degree air Id say your lungs would be exhaling the cabin pressure. I wonder if this rapid exhale is any good for the lungs.
while your are exhaling, one would be doning masks, switch mike audio to mask, activate the "rubber jungle" if it allready hasnt deployed simultaneoulsy emergency descent off the airway and advising ATC your actions, then a cabin announcement after that.All with that one exhaled breath! :):p
Nah only kidding. But the name of the game is to get DOWN ASAP and NOT deal with super chilled Oxygen difficient air.

My 2 cents worth.

Sheep.

P.S used to FLY unpressurised B90 King Airs on long hikes across the Gulf of Mexico and Carribean sea. Its lovely stuff Oxy,makes your mouth dry, and very hard to swallow cake and drink tea. But once you take of the mask off at say 22-26000 ft, the initial symtoms of hypoxia dont take long to develope, tunnel vision etc. From experience its pretty bad stuFF not recommended, only incontrolled decompression chamber conditions.

[Old Smokey]

Emergency breathing techniques? Don't even think about it. As indicated on another currently running forum, it's the Oxygen partial pressure (or lack of it) that's the killer. With certain breathing techniques you may be able to increase the air pressure SLIGHTLY, but to nowhere near the degree necessary.

Holding your breath? At 40,000 feet depressurised, to maintain Sea Level pressure inside your lungs would be a 12.0 PSI pressure differential. That's enough to burst any aircraft pressure hull.

Oxygen is the ONLY answer, and at higher levels, at 100% and under pressure.

Regards,

Old Smokey

[LEM]

Just to confirm my colleague was wrong...:E

Is there a difference between climbing at very high altitudes in an unpressurized plane, breathing oxygen, and being at the same high altitude in a pressurized plane, experiencing a sudden decompression?
(like suddenly opening a bottle of coke).
That was his point...

Does the second case make the blood boil, at least for a few seconds?

[NinerVictor]

The phenomena of blood boiling at high altitude is a fact. It is due to gas (Boyle's) laws. At about 62,000 feet, air comes out of solution (blood). This altitude is also known as the Armstrong's Line. This is why pilots who fly the U-2 and SR-71 high altitude a/c has to wear a full pressure suit, to avoid this unpleasant event. Colonel Joseph Kittinger, the man who did the world's highest altitude parachute jump at 102,800 feet also had to wear a pressure suit when he leaped off from the balloon!

[Blip]

So that scene in the movie "2001 A Space Odyssey" where Dave has to spend some 20 seconds or so in the vacuum of space without a space suit helmet while getting back into the mother ship is BS? Even HAL didn't think he could do it!

http://www.palantir.net/2001/sounds.html
"You're going to find that rather difficult."

[SR71]

William H Rankin, famous as The Man Who Rode Thunder, ejected from a F8U at in excess of 47000ft and M=0.82 and took 40 mins to get to the ground.

He was wearing no protective gear at the time although he was on oxygen at the time of the ejection.

You can read the story in Wild Blue, Pg 38-61.

[PAXboy]

scene in the movie "2001 A Space Odyssey" where Dave has to spend some 20 seconds or so in the vacuum of space without a space suit helmet I have always thought that! It was one of the resons I have always marked the film down. It was so patently not possibly for a human being to be in a total vacuum for 20 seconds and live.

Unless I mis-remember, this mistake was also made in one of the Alien series.
--------------------
"I tell you, we are here on Earth to fart around, and don't let anybody tell you any different." Kurt Vonnegut, Jr.

[Old Smokey]

It's appropriate that a discussion regarding the usefulness of "Emergency Breathing Techniques" at high altitude should have drifted into the realm of science fiction, because that's what it is - PURE FICTION.

To LEM's question - "Does the second case make the blood boil, at least for a few seconds?", the answer is YES. And the end result of a few seconds of blood boiling is about the same as the micro-second that it takes for a bullet to pass through your heart - You're Dead!

Emergency / Rapid breathing techniques at Medium altitude will lead to hyperventilation, unconsciousness, and death.

Regards,

Old Smokey

[LEM]

So now I'm really puzzled!...

Old Smokey, you mean a SUDDEN decompression at level 400 is fatal anyway?

It can't be! The whole aviation business would have to stop!

:confused: :confused: :confused:

[Old Smokey]

Not even remotely LEM, the "blood boiling" syndrome does not occur until well above 40000 ft, various sources differ, but in the vicinity of 60000 to 82000 feet.

Regards,

Old Smokey