Where to air up with NITROGEN... ?

Great way to insult probably the most informative source of engine build info on NAGTROC, yourgirlznext. You are quite a classy fellow. You could have phrased your reply much less 12 year old-ish.

I did humor you, because I didn't know about nitrogen asphyxiation , and did a Google search for "nitrogen deaths". Here is info from the first link. Where does it indicate "one deep breath of N2 can kill you".

A typical human breathes between 12 and 20 times per minute at a rate primarily influenced by carbon dioxide concentration, and thus pH, in the blood. With each breath, a volume of about 0.6 liters is exchanged from an active lung volume (tidal volume + functional residual capacity) of about 3 liters. Normal Earth atmosphere is about 78 percent nitrogen, 21 percent oxygen, and 1 percent argon, carbon dioxide, and other gases. After just two or three breaths of nitrogen, the oxygen concentration in the lungs would be low enough for some oxygen already in the bloodstream to exchange back to the lungs and be eliminated by exhalation. Crude simulation of oxygen transport through the lungs and blood stream suggests that the partial pressure of oxygen in arterial blood would be about 50 percent of saturation 1 minute after switching gases and would reach zero within 3 minutes.
Unconsciousness in cases of accidental asphyxia can occur within 1 minute. Loss of consciousness results from critical hypoxia, when arterial oxygen saturation is less than 60% (Fisher n.d.). "At oxygen concentrations [in air] of 4 to 6%, there is loss of consciousness in 40 seconds and death within a few minutes" (DiMaio & DiMaio 2001:231). As this procedure provides an atmosphere completely devoid of oxygen, the sequence of effects should be expected to occur even more quickly. At an altitude greater than 43,000 ft (13,000 m), where the ambient oxygen concentration is equivalent to 3.6% at sea level, an average individual is able to perform flying duties efficiently for only 9 to 12 seconds without oxygen supplementation (Fisher n.d.). The US Air Force trains air crews to recognize their individual subjective signs of approaching hypoxia. Some individuals experience headache, dizziness, fatigue, nausea, or euphoria, but some become unconscious without warning (Fisher n.d.). Equivalent training is unlikely for a condemned individual, making unconsciousness without warning probable, although as much as a 30 second warning is possible.
Loss of consciousness may be accompanied by convulsions (Fisher n.d.) and is followed by cyanosis and cardiac arrest. About 7 minutes of oxygen deprivation causes death of the cerebral cortex and presumably the medulla oblongata, which controls breathing and heart action.

drjpwaldo said:

+1

Funny, though, how a lot of things which are harmless in everyday situations can become deadly when we are just a little careless. A little knowledge and training goes a long way. I agree with the spirit of yougirlznext's warning. Things just got a little weird after that!

John P Waldo, MD A.B.R.

Click to expand...

Agreed, but a TAD exaggerated. It's this kind of stuff that I have to "de-educate" patients about. Lots of old wives tales, and "common knowledge" and "safety training" just --- "isn't". Isn't correct, isn't safe, and often isn't even near the truth. This particular one -- N2 isn't any more dangerous than helium. How many goofballs (including the entire host cast of "Top Gear") have you seen FULLY inhale total lungfulls of basically pure non-oxygenated gasses? My own personal eyes have witnessed numbers in the hundreds, including a friend of mine and his wife (both doctors) who got married with the entire speaking cast of the wedding talking only with helium.

How many bad outcomes? One. Guy passed out backwards. He was just fine when his sleep respiratory center took over because he was holding his breath. Still a friend of mine from high school on Facebook. Doesn't seem like any permanent damage (but he didn't really start out totally "RIGHT" anyway).

There are THOUSANDS of ways to get killed working on cars. This one is about as likely as getting hit from a piece of space debris falling from the sky. Not impossible, just REALLY unlikely. Exploding tires from overinflation, cars falling off jacks, wheels falling off from incorrectly torqued wheels, springs flying acrosss rooms from suspension work, neckties and necklaces caught in fan blades bending over engine bays while the engine is still running (how many of us have tempted fate with THAT little poorly considered idea?) are just SO much more likely, but how many of us chime in with the "one time you get under a car supported improperly could be your last?". Not often.

This seemed a TAD excessive. Given, the response was also a TAD excessive. But, running around a car forum with heart on your sleeve is just kinda silly. I understood the spirit of the warning, but it's in the same ballpark as rolls of duct tape saving you from terrorist attack.

Shawn