Nitrogen or Oxygen

[robbiep]

Hi. Many thanks. That clarifies it, and we're on the same wavelength. Our BSAC club stores premix Nitrox and we do tri mix too. My oddest narc was diving Truk Lagoon (sorry!). We were looking at the video clip of a deep dive. The camera told us we were there but neither of us could remember it. Scary stuff!

 

From my knowledge of diving gases I would put nothing through a PCP other than compressed air

 

Not done Truk (yet!), but it's certainly on the list. We're off to Australia in a few weeks, hope to get some diving in while we're out there. Have done the reefs, there are a couple of wrecks we want to do this time.

[Bewsher500]

 

Same for pure nitrogen. Imagine what happens if the valve fails and your tank vented while in the car, while you were driving along. Instant lack of oxygen, you suffocate in your seat in seconds.

 

really?

you are breathing over 70% Nitrogen....

 

1l bottle at 200 bar is 200l of gaseous Nitrogen at 1Bar (atmospheric).....

your car holds 1000's of litres....

[Billy.]

 

really?

you are breathing over 70% Nitrogen....

 

1l bottle at 200 bar is 200l of gaseous Nitrogen at 1Bar (atmospheric).....

your car holds 1000's of litres....

 

If a bottle of nitrogen leaked in your car, you'd more than likely crash due to hypoxia. The gas wouldn't kill you per se, but you'd pretty much be drunk on a lack of oxygen and have absolutely no clue you were behaving any other way. A drop of 8% in oxygen will be enough to put you into a hypoxic state, you don't need to get rid of all the oxygen in a car.

 

Death by hypoxia is thought to be one of the best ways to go. You have no idea it's happening and eventually fall asleep.

Edited August 25, 2015 by Billy.

[deershooter]

I can see a Darwin Award coming here !

[Bewsher500]

 

If a bottle of nitrogen leaked in your car, you'd more than likely crash due to hypoxia. The gas wouldn't kill you per se, but you'd pretty much be drunk on a lack of oxygen and have absolutely no clue you were behaving any other way. A drop of 8% in oxygen will be enough to put you into a hypoxic state, you don't need to get rid of all the oxygen in a car.

 

Simply not true

8% O2 will kill you alright or at the very least seriously put a crimp in your day ....but the getting to 8% is the bit that doesn't stack up

 

you will need to show your working on this one I am afraid

 

Lets just say for argument sake you are driving a Ford Focus (heaven forbid!)

a 4 door mid size car car has an internal volume of up to 3.37m3 (https://en.wikipedia.org/wiki/Vehicle_size_class)

1000 l3 in 1m3

3.37m3 = 3373 l3 of gas

 

78% N2

20% o2

everything else negligible for the purposes of this discussion

 

thats 2630 l3 of N2 vs 708.33 l3 of O2

if you increase the pressure internally with an additional 200l3 of N2

in order to accomodate it you will either have to displace 200 l3 or raise the pressure of the vehicle, as it is not sealed assume the former

 

200 l3 of displaced gas..

78% of which is already N2!

21% of which is o2

 

so you are displacing 21% of 200l3 of O2 ....approximately 42 l3 of O2

 

42 l3 from the original 708l3 is 666l3 approximately 6% of TOTAL volume

 

666 l3 of O2 in a void of volume 3373 l3 is an approximate level of 19.74%

 

A drop in oxygen concentration of less than 1.5%

That is assuming a sealed vessel with only exhaust vents to allow displaced gas to leave....not having 6 mahoosive ones in the dash and at least two mahoosive ones in the boot allowing a constant flow of replaced FRESH AIR......so likely the figure would be less, potentially significnatly less than 1.5%

If cars didnt flush air as you drove you would die faster from CO2 poisoning on every long drive in winter !

 

18% is the commonly understood minimum level of O2 required for normal symptomless existence

 

Summary

You and your buddy bottle will be safe in the car should you choose to ignore warnings and fill your bottle with Nitrogen......

 

http://www.linde-gas.com/internet.global.lindegas.global/en/images/Hazards%20of%20inert%20gases%20and%20oxygen%20depletion17_13909.pdf

[la bala]

After reading these posts, i now have a headache.

[Billy.]

 

Summary

You and your buddy bottle will be safe in the car should you choose to ignore warnings and fill your bottle with Nitrogen......

 

http://www.linde-gas.com/internet.global.lindegas.global/en/images/Hazards%20of%20inert%20gases%20and%20oxygen%20depletion17_13909.pdf

 

Show me where I said buddy bottle

 

I also said a drop in 8%, not 8% total. I also didn't directly attribute that figure to the car.

Edited August 27, 2015 by Billy.

[ditchman]

use NO2...nitrous oxide...........then if you miss you can have a good larrf.............

 

 

sorry i will get my coat.............

[Kalahari]

There are a couple of things here that are not correct. Nitrogen Narcosis is not the bends. Nitrogen Narcosis, being "narced" used to be called rapture of the deep. It is a mental effect of nitrogen under pressure when you become excessively relaxed and unaware/uncaring of risk. The bends is caused when you surface too fast for the dive and bubbles occur, often in the joints which causes crippling injuries. They can also occur in the blood and the brain with somewhat nasty effects.

 

What this has to do with PCP airguns I am not entirely sure. However many PCP bottles are what divers use as emergency bottles for ascent when difficulties happen in your main breathing circuit. Therefore if there was confusion at the filling station you could kill a diver. Perhaps air is really the best option.

 

David.

Edited August 27, 2015 by Kalahari

[Bobba]

...........However many PCP bottles are what divers use as emergency bottles for ascent when difficulties happen in your main breathing circuit. Therefore if there was confusion at the filling station you could kill a diver. Perhaps air is really the best option.

 

David.

Not understood at all. Please explain. What are these "PCP bottles" you say that divers use? What do you mean by breathing circuit? eg are you referring to open circuit or closed circuit (rebreathers)? What will confuse the filling station to the point that that confusion could kill a diver? Finally, are you a qualified diver? If so, agency and level please.

 

I ask because I've not read such rubbish for many a year.

[Kalahari]

Thanks ever so much for your comment. I notice several posts have been amended to cover the points I raised, so possibly not quite as much rubbish as you say! Also some of the bottles used in PCPs are identical to the ones some divers use as "pony" bottles, hence my warning.

 

David.

[Bobba]

I agree with the first part of your post about "narcs" and "DCS" (which can be gleaned from any Google search) and that others have made amendments to cover those points. But you have not answered any of my questions concerning the second part of your post on cylinders. Nor have you enlightened me on any qualifications you hold which give you insight into what you seem to believe in.

My concern is that those PW members who know nothing about such matters will take your word as Gospel when, in fact, it doesn't even measure up to a Janet and John book.

[Kalahari]

My comment about cylinders is covered, try reading the bit about some PCPs using the same cylinders as some pony bottles. If stuff goes in to be filled you cannot be sure that errors cannot be made. Hence the rule in diving about measuring your nitrox yourself before you dive. The contents don't always match the label, even if errors are very rare.

 

Advanced Open Water, Nitrox ticket, 15 years experience.

 

David.

[Bobba]

Hello David, thanks for your openness. If I went into filling station protocols, cylinder markings, test requirements etc our PW colleagues would quickly go to sleep. and these are some of the reasons why I disagree with you.

 

If I appear over sensitive it's perhaps with your use of "kill a diver". A subject not talked about. Yet, sadly, this year our club lost a leading member who was diving on the wreck of th Aparima. He was a personal friend for over 20 yrs.

 

As you were courteous enough to share your tickets It is only proper that I do likewise. BSAC Advanced Diver, Open Water Instructor, Practical Rescue Management Instructor, Nitrox Instructor, compressor operator ticket, TDI (Technical Diving International ) gas blender - Nitrox, IANTD (International Assoc of Nitrox and Technical Diders) Advanced Nitrox Diver. RYA powerboat ticket. Sadly, aged 70 and with over 20 yrs of fun the old arthritis kicked in (new hip and they want to do my knees!!) so I have reluctantly hung up my twinset (300 bar 7's) and increased my pigeon shooting etc

Good luck with your diving

Bob

[evo]

Hello David, thanks for your openness. If I went into filling station protocols, cylinder markings, test requirements etc our PW colleagues would quickly go to sleep. and these are some of the reasons why I disagree with you.

 

If I appear over sensitive it's perhaps with your use of "kill a diver". A subject not talked about. Yet, sadly, this year our club lost a leading member who was diving on the wreck of th Aparima. He was a personal friend for over 20 yrs.

 

As you were courteous enough to share your tickets It is only proper that I do likewise. BSAC Advanced Diver, Open Water Instructor, Practical Rescue Management Instructor, Nitrox Instructor, compressor operator ticket, TDI (Technical Diving International ) gas blender - Nitrox, IANTD (International Assoc of Nitrox and Technical Diders) Advanced Nitrox Diver. RYA powerboat ticket. Sadly, aged 70 and with over 20 yrs of fun the old arthritis kicked in (new hip and they want to do my knees!!) so I have reluctantly hung up my twinset (300 bar 7's) and increased my pigeon shooting etc

Good luck with your diving

Bob

crickey bobba,,,,,,,,,,,,,,,,,,,, can you swim by anychance :lol:

 

good on you sir,, could of done with you when I dropped the sledgehammer in our lake