999

[BigJetDriver]

it's the third article down

Good link, Andy. Thanks! Oh, and by the way, is that "Mother Gator" or "Mutha' Gatuh"?

Cheers!

 

[H2Andy]

lol...

i think it's interesting that 10/20 ppm is max "safe level," but cigarette smoke
contains 400 ppm, and that is not toxic. at 3000 ppm, the person passes out.

so "poisoning" happens at a higher CO level than 400 ppm, but i can't find anywhere
that says what that threshold level is.

oh well

 

[String]

Try http://www.boatwashington.org/carbon_monoxide.htm

From elsewhere i read 800ppm is the dangerous point.

I cant find my COSHH risk assessments from the lab any more which is a pity, i KNOW its on there.

Again dont forget that a safe concentration at 1 atmosphere can be double at 10m depth and so on so even "safe" amounts may cause problems at depth.

 

[Warren_L]

lol...

i think it's interesting that 10/20 ppm is max "safe level," but cigarette smoke
contains 400 ppm, and that is not toxic. at 3000 ppm, the person passes out.

so "poisoning" happens at a higher CO level than 400 ppm, but i can't find anywhere
that says what that threshold level is.

oh well

I don't know if the 400ppm level in cigarette smoke is true or not, it might be. However, from my understanding, levels up to 70 ppm at regular atmospheric pressure should not present problems to most people. Once you get up above that, the problems begin. I believe critical levels would be about 150 ppm or above. With cigarette smoke, it would seem that when smoking a cigarette, you are not breathing 100% cigarette smoke continuously for an extended period of time, which would then drop your CO exposure to to levels at which you may not exprience the effects of CO poisoning. At 3000 ppm, I would think passing out would be an understatement.

But also remember that for compressed breathing gas, 20 ppm, physiological exposure is the equivalent of about 80 ppm at 4 ATA (or 100 ft depth).

 

[String]

Exposure time is an issue too. Smoking you arent breathing it constantly, only a few mins at a time. SCUBA you are breathing that concentration gas for 45 mins to maybe an hour or so constantly with no air breaks.

 

[Web Monkey]

I was just watching an old episode of 999 (UK television) and saw a bit about a dive group who got a load of bad fills and ended up with a huge amount of carbon monoxide in their air. This caused one of the divers to have to surface rapidly because she couldnt breathe. Can this happen (the Co) and if so what would you recommend to be the best course of action?
It also happens that on the way to the hyperbaric chamber the helicopter had to rise over a range of hills and the woman went into spasms of pain as the chopper got higher. Does this happen or is it rare???

I hope this doesn't start a new Pony bottle war, but that's another good reason to bring one.

The chances of getting a bad fill wherever you're going, along with a bad fill on your pony (filled somwhere else) are pretty slim.

Terry

 

[String]

How many people though would deliberately get a fill for a reserve air source elsewhere ?

Certainly here everyone tends to get everything filled in the same place so chances are your buddy will have bad fill too.

I agree in theory a redundant air source with a fill obtained somewhere else is a good idea but not always practical (plus of course your primary maybe fine but after a reg problem you switch to your backup to find THAT has a bad fill...).

 

[FreeFloat]

Try http://www.boatwashington.org/carbon_monoxide.htm

From elsewhere i read 800ppm is the dangerous point.

I cant find my COSHH risk assessments from the lab any more which is a pity, i KNOW its on there.

Again dont forget that a safe concentration at 1 atmosphere can be double at 10m depth and so on so even "safe" amounts may cause problems at depth.

CSA Standard Z180.1-00 states that CO concentrations in compressed breathing air cannot exceed 5ppm. I'm looking for more references, but I have an entire bookcase to look through...........

 

[FreeFloat]

Okey dokey

Disclaimer: I am not in any kind of medical profession, I work mostly in clerical roles so while researching references is one of my strengths, I can only quote directly out of the reference - do your own research if you'd like more details or questions answered.

From the "Documentation of the Threshold Limit Values and Biological Exposure Indices, Sixth Edition" produced by American Conference of Government Industrial Hygienists Inc. :

Carbon Monoxide:

"A [Threshold Limit Value - Time Weighted Average] TLV - TWA of 25 ppm is recommended to keep blood COHb levels below 3.5%, to minimize teh potential for adverse neurobehavioral changes, and to maintain cardiovasular exercise capacity. This recommendation also provides a margin of safety for individuals particularly susceptible to the adverse effects of carbon monoxide exposuer..."

 

[Web Monkey]

How many people though would deliberately get a fill for a reserve air source elsewhere ?

It's not as silly as it sounds.

When diving locally, I get fills from a shop I trust, that spends a ton of time and money making sure that their air is clean, and regularly certified.

When diving elsewhere, I get it filled at a shop that has known-good air, before diving with an unknown operator.

Terry