New Fine Woodworking magazin almost made me ill

"IIRC"? That is a big IF!

You are partially right. If increase the normal air nitrogen content from 78% to 90% or 95%, there is precious little room for oxygen. But I suspect you would experience shortness of breath.

Maybe you were thinking of carbon monoxide?

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Reply to
alexy
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I found this on the internet, it has to be true...

From

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best Earthly comparison is what happens to people who walk into a room containing a pure-nitrogen atmosphere. The analogy is fairly good; to a first approximation, when there's no oxygen present, it doesn't matter whether something else is there or not. Such accidents happen occasionally in industry. (In fact, one happened at the Ariane 5 launch site a few months back.) Sudden loss of consciousness occurs within

10-15s, and death follows quickly. Stringent precautions have to be taken to prevent such accidents, because survival is rare -- you get no warning that you're about to keel over, and rescuers must understand the situation immediately and act very quickly.

Also, Clarke got one detail completely wrong: hyperventilating first will not help. The bloodstream of a resting person is already saturated with oxygen; there is no way to pump more in. What hyperventilation does is to flush CO2 out of your body. This matters because the breathing reflex is triggered by CO2 buildup, not oxygen shortage. (That's why you get no warning of impending unconsciousness in a pure-nitrogen atmosphere.) Hyperventilation suppresses the breathing reflex so you can fully exploit the air in your lungs. This doesn't help in vacuum.

(I suppose I should also observe here that deliberate hyperventilation to help you hold your breath -- in situations like diving -- is dangerous, for an analogous reason: it's possible to suppress your breathing reflex so thoroughly that you run out of oxygen before you feel any need to breathe, and the result is sudden unconsciousness.)

Pulling out quotes.

"Sudden loss of consciousness occurs within

10-15s, and death follows quickly. Stringent precautions have to be taken to prevent such accidents, because survival is rare -- you get no warning that you're about to keel over, and rescuers must understand the situation immediately and act very quickly."

"This matters because the breathing reflex is triggered by CO2 buildup, not oxygen shortage. (That's why you get no warning of impending unconsciousness in a pure-nitrogen atmosphere.)"

"it's possible to suppress your breathing reflex so thoroughly that you run out of oxygen before you feel any need to breathe, and the result is sudden unconsciousness."

I'm quitting googling and going back to work. I'm still open for more/better information on the danger of a pure nitrogen atmosphere and its effect on us humanoids.

-- Mark

Reply to
Mark Jerde

Patriarch mentions:

Note the number of lighting circuits I mentioned. Three. And nothing else on any.

But you can get nailed anyway: over a decade ago, I had a basement shop in the City of Bedford. I was working on a project book, and made a habit of going in early because the city electric company (still owned by the city) seemed to me to make a habit of shutting things off almost every day. I figured I could plane and joint and tablesaw to my heart's content before 7 a.m. And be damned if twice they didn't pop the power before 6:30 a.m.!

Short interruptions, maybe 7 or 8 minutes, but in a one window shop, when it's still dark out, that is no fun.

Charlie Self "Health nuts are going to feel stupid someday, lying in hospitals dying of nothing." Redd Foxx

Reply to
Charlie Self

Our computer room at work has an FM200 fire supression system, basically the new version of halon. The room is maybe 1000 square feet.

We had a very minor fire that cut the power and triggered the fire supression system. It cost over $12,000 to have the gas cylinder refilled.

I doubt any woodworker could afford one of these unless it was a commercial business.

Brian Elfert

Reply to
Brian Elfert

Interesting.

I would have thought you would get shortness of breath. But I understand hypoxia due to altitude works much as you describe. People's judgment and mental capacity decreases, but they do not recognize it.

Here are two posts from a thread that appeared on rec.aviation.piloting a few years ago when a golfer's jet decompressed an flew until fuel exhaustion. The question was why the pilots couldn't recognize it and get down. These posts tell of people's experience in a hypobaric chamber, which shows their rapid incapacitation.

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?q=g:thl3691800605d&dq=&hl=en&lr=&selm=3818FB10.4C291D24%40bellsouth.netAnother post in the thread tells of similar disorientation occurring much more slowly (~15min) when altitude was raised to only 18,000 feet.

So, back to your original post, nitrogen itself is certainly not poisonous, or even harmful, but if it displaces oxygen, the resulting hypoxia kills quickly and without much warning, as you described.

Reply to
alexy

Pi approximately = 3.14159 26535 89793 23846 26433 83279 40288 41971 ... I have verifiable memories from 1960 before I was a year old. My memory is either a gift or a curse. Since I'm *not* *rich* it must be a curse ... ;-) It's a hell of a burden to recall 45 years of accumlated failures in

3D, TechnicalColor detail....

BTW I *SUCK* at most things. In scientific terms I have "narrow bandwidths of more-than-minimum competence." Einstein said that everyone was somehow his superior; I know that almost everyone is in nearly every way better at everything than I am. ( Ask my wife and kids....)

F*ck.

-- Mark

Reply to
Mark Jerde

Can't speak to the OP, but if I were doing it with a single switch, that switch would energize a set of contactors (read: relay), one to a circuit. Turn off the switch (could even be 12v) and the contactors open - voila, no power to tools.

scott

Reply to
Scott Lurndal

Yup. Make sure whatever you buy is NFPA-13 compliant.

Reply to
Dave Hinz

We were able to "drop in" - more or less - FM1200. It used the same distribution pipes but required a larger canister.

Reply to
GregP

A friend of mine climbed Mt. McKinley in Alaska in 1978. I wanted to go but couldn't get all the $$ together. His description of insuffient oxygen was interesting: "It's not like being high, it's like being stupid." All the members of the expedition had an altitude at which they "became stupid." My friend Jon made it higher than most but he was "out of it" near the peak and has few memories of the last part of the climb. He has photos, and these are the basis of his "reconstructed recollections" of the last part of the climb. ;-)

By his description as they walked back down the mountain people "snapped out" of their IQ-65 mode back to normal at the same altiudes they lost it on the way up.

-- Mark

Reply to
Mark Jerde

Yeah, I've just got one 20 amp circuit going from the garage out to the shop. I don't yet have any big tools other than my 17amp PSI dust collector, and I'll tell you that it dims the lights right down on startup.

Overall I agree with you, but the number of outlets in a shop is irrelevant, what matters is how much you're drawing, and 45 outlets just sitting there don't tend to draw much ;) I just use two tools at a time. My contractor's saw, in thick stock, with the DC, can trip the breaker, but that situation is rare (twice in 5 years?).

My plan is to run a 220V circuit out there to a subpanel with the 20A circuit, and have that panel's main switch shut everything down. Then I'll move the DC to 220 and put the contractor's saw out to pasture for a cabinet saw. I REALLY like having the whole shop on one switch though.

-Mike

Reply to
Mike

Scott Lurndal responds:

Yeah, well...I guess it can be done that way, but it does seem like a peepot full of extra work for no particular reason I can see. For a basement shop where toddlers and teenagers had room to roam, it might make sense, but in my shop, I shut off the machines, slap the light switches down and cross the yard to the house.

I don't see a need for a single switch, because even with the toddlers and teens, it's easy to beat.

Charlie Self "Health nuts are going to feel stupid someday, lying in hospitals dying of nothing." Redd Foxx

Reply to
Charlie Self

Mike responds:

Yeah, well, that's either 8 or 9 circuits, with two extending to a few outdoor outlets that might get used for whatever while I'm working inside. I seldom have more than 3 outlets occupied and drawing at a time, unless a friend is over, but I also run studio strobes and hot lights off the same outlets, so need every one--sometimes.

It would take a bank of switches to shut it all off, I'm afraid.

Makes sense.

Well, I prefer having the lights on separate channels, as it were, and I've got an electric furnace on its own 60 amp breaker, if I ever get to the point of hooking up the blinking thermostat.

But why is having a single shut-off important to you?

Charlie Self "Health nuts are going to feel stupid someday, lying in hospitals dying of nothing." Redd Foxx

Reply to
Charlie Self

I suppose this is strictly true. There is nothing wrong with nitrogen.

My point is a nitrogen-only atmosphere will cause death in humans, and the humans will have no advanced notice of the danger.

Hence the (perhaps wrong) potential danger of Halon fire suppression systems that use nitrogen.

Again, I welcome more and better information. I know I often get things wrong.

-- Mark\

Reply to
Mark Jerde

Mark, I think the difference is that here we are talking about nitrogen as a propellant, which would dilute the oxygen content somewhat. In the NASA case, nitrogen was used in large quantities to displace the air. To put it in silly terms, spaying water on the fire will raise the humidity of the room, but not hurt the human occupants. Flooding the room with water to remove all of the air will result in drowning.

Reply to
alexy

Long ago when I was in the air force (about 1955) and on flying status we were required to go through high altitude training. In a pressure chamber we were brought to an altitude of 40,000ft. then every other man in the chamber unplugged from his oxygen then started to write his name on a clip board after what seemed like a couple of seconds his partner plugged him back in. In just a couple of signings the writing from neat to an unreadable scrawl. Then a volunteer was selected (military remember) told to stand with his arms out like an airplane, he was unplugged and given commands to bank right, bank left, climb, dive. After the bank left command he just stood in that position until he was plugged back in to the oxygen. I always thought what an easy way to go no pain no strain your just gone. It was also one lesson that stayed with me every time I flew.

Bob P. making sawdust in Salem Or.

Reply to
RPRESHONG

snipped-for-privacy@aol.comnotforme (Charlie Self) wrote in news: snipped-for-privacy@mb-m07.aol.com:

I saw that, Charlie. My comment related to the OP.

Power outages would seem to call for backup lighting on batteries, at least to some small degree.

Another thing for the to do list.

Patriarch

Reply to
patriarch

A google search for "nitrogen asphyxiation" turns up a lot of hits. This looks like a good one:

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quote:

"While nitrogen makes up the majority of the air we breathe and is not toxic, people shouldn't assume it's benign," according to CSB Chairman Carolyn W. Merritt. "Nitrogen does not support life, and when nitrogen displaces the oxygen we breathe, it can prove very deadly. Since nitrogen is odorless and colorless, our senses provide no protection against nitrogen-enriched atmospheres. Good safety management practices are essential if we are to reduce the annual toll of nitrogen-related deaths and injuries."

R, Tom Q.

Reply to
Tom Quackenbush

I agree I have probably fixated on an obscure and basically irrelevant point. ;-) That's my MO.

Doubtless halon was/is an effective fire suppressor.

Sorry for the diversion... ;-) I specialize in obscure and irrelevant....

-- Mark

Reply to
Mark Jerde

Things must get more violent in your shop than mine. The light bulbs hang out at that same level. Can't remember ever breaking one of them.

bob g.

Doug Miller wrote:

Reply to
Robert Galloway

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