I hope this story scares the hell out of you!

Like I.N. said. Respiration is keyed to sync with the Krebs cycle. The case of there somehow not being enough oxygen in a breathable atmosphere just isn't a situation we are adapted to.

Oxygen is used as a metabolic regulator, but not to control respiration. It is used to stimulate wound recovery and generate new blood vessels.

Basically, Oxygen is the item that regulates balance of energy within the tissue through angiogenesis, while CO2 gets used for syncing the body with its environment through respiration. Tissue O2 levels are crucial to regulating the development of the foetus and for wound repair. Mountain climbing and mucking about in cargo holds seem to have garnered short shrift compared to those.

 

Alaska

"A 59-year-old, male barge operator was asphyxiated as a result of entering the oxygen-deficient atmosphere in a compartment of a stationary barge...iron oxidation due to rust formation resulted in extreme oxygen-depletion. While the level of rusting observed seemed to be normal for a vessel of this age, areas of "black rust" were observed. "Black rust" has been reported to reduce oxygen content to less than 5 percent"

Scotland:

"Two Scottish companies have recently been fined following the deaths of two workers in the confined cabin space of a barge where they were trying to rescue a third colleague.
The two men were asphyxiated shortly after entering an oxygen depleted space on the barge – the rusting of the boat’s metal hull had consumed most of the oxygen in the small closed chamber"

Holland:

"A crew member of a coaster loaded with scrap metal tragically lost his life when entering the hold that had been closed for several days at least. Fire fighters from Amsterdam were called in to check the oxygen level in the hold. At the top of the stairs the level had already fallen to 16 % . At the bottom of the hold the oxygen level was only 8%!
The reason for this low oxygen level is probably oxidation of iron, both of the ship and of its load"

 

If there is a high level of CO2 from combustion in the engine space is iti likely you would notice that because you get a reverse osmosis of the highly soluble CO2 ?

In an enclosed space where the oxygen level is reduced and the balance is not CO2 but just nitrogen you still get rid of your CO2 and don't suffer respiratory distress, and the victim would just blank out with hypoxia in that situation.

Then both the oxygen reduction from the rusting process and carbon monoxide poisoning would have very similar outcomes in that you'd be unaware of problems and comfortable up to the point of collapse.

 

MJ,

I see you're an engineer, that explains a lot.

So, you're familiar with partial pressures?

 

My wife would probably agree with you

But I'm learning from this and since I am able to have a lot of input into safety issues on site I'd like to try and understand a few things. I'm not worried about absolutes just quick dirty, is it feasible. And my chemistry is rusty I'm sorry.

While I have your ear, if you do know about this, are you aware of any studies on the survivability of CO2 flooded spaces and the human response times ?

 

Whatever the theory, and the exact figures, be extremely careful when entering confined spaces, or working with fuel burning aparatus. (engines, heaters)

I recall having rented a caravan, to spend the weekend with my wife and 2 kids. It was pretty cold outside, and inside was a gas heater, of an open type. I used it to heat up the caravan in the afternoon. After a while I developed a headache. As itwas 21:30, I decided to go to bed, and when shutting off the heater, I noticed the flames being yellowish, instead of blue.
The night was freezing cold, the kids could hardly sleep from the cold, and we had trouble as well. I complained the next morning, and the remark was that I just should have left the heater on. I decided to leave and go back home. I have no idea if we would have survived, but I did not find it worth the risk.

On sea ships which are to be docked, the yard usually orders to have the ballast tanks that should be worked on full with water. As these are drained, fresh air is drawn into the tank. Saves a couple of funerals.

 

Probably short.

A few years ago I saw a superyacht who used CO2 as a defense. The owner was concerned for his safety due to many enemies. ...if intruders made it past the yachts first three layers of defense, the owner would take shelter in the aft cabin, then trigger CO2 gas cylinders to flood the inside of the yacht with gas.

I remember the yacht because no service contractor would take legal responsibility for servicing and proving the CO2 system.

The same applied to the yachts electrified SS lifeline wires.

 

Yes you are correct from the information I can find, it's only the lower levels that lead to respiratory distress and a clear indication that somethings wrong. At higher concentrations in the air it's quite toxic. So the CO2 systems are quite dangerous, and the system is manually activated but the CO2 alarms are often turned off when the vessel is not in use.

Symptoms from Low to High Concentrations of CO2

%CO2 Symptoms

2 to 3 Shortness of breath, deep breathing

5 Breathing becomes heavy, sweating, pulse quickens

7.5 Headaches, dizziness, restlessness, breathlessness,
increased heart rate and blood pressure, visual distortion

10 Impaired hearing, nausea, vomiting, loss of consciousness

30 Coma, convulsions, death

 

I can't believe I am saying this, but you are right.

 

Be careful. It could become habit-forming...

 

If you regularly enter confined spaces, such as surveying jobs, this could save your life. Depending on the model, it can detect oxygen level, CO, and other poisonous gases. Expensive yes but if your job requires it, it is worth it.

You probably have heard of the surveyor who always bring his caged pet canary. Before he enters a hold, he would lower his canary to the hold. If after hoisting it and finds the canary alive, only then will he enter the hold. I don;t know if the story is true.

 

I don't know about the surveyor, but they used to use canaries in coal mines as air monitors. I was surprised to read in Wikipedia that their use in British mines wasn't phased out until 1987.

 

Not likely.

 

Probably some canary hugger made them stop.

 

I like to be prepared,have a lot of freeze dried food,good for 30-40 years etc and have my own stuff (canning,pasta,dried fruits,meats etc) and without oxygen and staying dry- most foods will last a very long time.

Various oxygen absorber packs are on the market-in a gallon jar that is full-ish, you put one in there and it'll take the oxygen down to .2 % within 2 hours.
Each package is maybe 1/2 teaspoon of powdered iron oxide.