Cup of tea without the Carbon monoxide please

[motacyclist]

Was this measurement made with the windows cracked open or the roof up?

No, I windows closed and roof down, never thought the oxygen would deplete that fast; since then we always make sure fresh air can get in.

 

[kp64zl]

Hi @motacyclist --quick question, can you remember how fast did the oxygen go down? and to what level?

We know a lot about safety of low oxygen (hypoxia) from mountain and aviation studies, for example the amount of oxygen in the atmosphere is as follows:

1) at sea level is about 150mmHg (say 100%),
2) cabin pressure in a standard commercial airliner is about 127mmHg (or equivalent to about 84% of sea level) (we would probably agree that's safe),
3) some of the higher ski resorts about 113mmHg (or about 75% sea level) (also we would probably agree this is safe for most people).
4) it's only at about the altitude of the high ski resorts that people start getting mountain sickness due to the low oxygen levels (& that's after about 6-8 hours exposure) and you would need to go a lot higher to start having serious reactions.

If would be interesting to know how low the oxygen went in the van.

My gut feeling is that there are other risks (as described in this thread) that are greater potential hazards than low oxygen, but that's just a guess based on my understanding of hypoxia physiology rather than van o2 measurements!

 

[MattBW]

I once tested a small gas heater in a T25 van, with a CO alarm to see how long it took. Suffice to say it took less than 30 minutes to trigger the CO alarm. I dont know at what level the CO alarm triggers or where that is on the safety timeline but it convinced me not to use gas heaters thats for sure.

 

[Bellcrew]

Hi @motacyclist --quick question, can you remember how fast did the oxygen go down? and to what level?

We know a lot about safety of low oxygen (hypoxia) from mountain and aviation studies, for example the amount of oxygen in the atmosphere is as follows:

1) at sea level is about 150mmHg (say 100%),
2) cabin pressure in a standard commercial airliner is about 127mmHg (or equivalent to about 84% of sea level) (we would probably agree that's safe),
3) some of the higher ski resorts about 113mmHg (or about 75% sea level) (also we would probably agree this is safe for most people).
4) it's only at about the altitude of the high ski resorts that people start getting mountain sickness due to the low oxygen levels (& that's after about 6-8 hours exposure) and you would need to go a lot higher to start having serious reactions.

If would be interesting to know how low the oxygen went in the van.

My gut feeling is that there are other risks (as described in this thread) that are greater potential hazards than low oxygen, but that's just a guess based on my understanding of hypoxia physiology rather than van o2 measurements!

As long as the CO2 scrubbers fit in the round containers we should all be OK.

 

[WelshGas]

People worry about Carbon Monoxide in a California but that is really only a problem if a combustion source is in use that is undergoing " incomplete combustion ", yellow rather than blue flames.
When sleeping you are unlikely to have such a combustion source going within the vehicle. If you are then you are Stupid and Darwins theory is about to be invoked.
However, when sleeping, 1 or more persons, then there can be serious depletion of Oxygen levels and a consequential increase in Carbon Dioxide. This increase in Carbon Dioxide can mitigate the drop in Oxygen to a degree by making it easier to absorb sufficient Oxygen, upto a point.
If you ever wake up feeling as if you have a head full of cotton wool or an element of nasal congestion then you probably have inadequate ventilation within the vehicle.
I mean, how many people would normally sleep in your single Box room at home?

 

[motacyclist]

Hi @motacyclist --quick question, can you remember how fast did the oxygen go down? and to what level?

We know a lot about safety of low oxygen (hypoxia) from mountain and aviation studies, for example the amount of oxygen in the atmosphere is as follows:

1) at sea level is about 150mmHg (say 100%),
2) cabin pressure in a standard commercial airliner is about 127mmHg (or equivalent to about 84% of sea level) (we would probably agree that's safe),
3) some of the higher ski resorts about 113mmHg (or about 75% sea level) (also we would probably agree this is safe for most people).
4) it's only at about the altitude of the high ski resorts that people start getting mountain sickness due to the low oxygen levels (& that's after about 6-8 hours exposure) and you would need to go a lot higher to start having serious reactions.

If would be interesting to know how low the oxygen went in the van.

My gut feeling is that there are other risks (as described in this thread) that are greater potential hazards than low oxygen, but that's just a guess based on my understanding of hypoxia physiology rather than van o2 measurements!

I'm not familiar with expressing oxygen levels as mmHg, our monitor gave readings in percentages. I should imaging the percentage would be the same irrespective of altitude, although the air would be less dense higher up, and therefore contain less O2 per lungful. It was a long time ago, but if my memory serves me correctly the O2 level dropped to about 18.5% (21.5% is normal) before the kettle boiled. It wasn't low enough to trigger the alarm on the gas monitor.

There was no indication of carbon monoxide. (The only time I've seen the CO alarm go off was when I was in a ship's double bottom under the engine room. I got out of there pretty quick!)

 

[kp64zl]

Hi @motacyclist -- at altitude the air becomes thinner as the ambient pressure drops and it's actually the pressure of Oxygen that counts to the body, not the %, although at a given ambient pressure the two are directly related.

Simple example is that at sea level the ambient pressure of oxygen is approximately 150mmHg, which is about 21% of air (the total pressure about 760mmHg = 100%)

At Everest base camp, ambient pressure is approximately half (i.e. approximately 400mmHg) and although oxygen is still 21% of the mix, the body has approximately half the oxygen available to it (because it's the pressure not the % that matters).

What this means is that we can learn from how the body reacts at altitude to infer what may be relevant in terms of oxygen depletion in a van (due to combustion).

According to this chart (http://www.geography.hunter.cuny.edu/tbw/wc.notes/1.atmosphere/high.altitude/partial.pressure.html)

18.5% inspired oxygen (which is approximately 88% of sea level) would approximately be equivalent to 1000metres altitude -- i.e. lower than most ski resorts -- so on its own is very unlikely to be harmful in any way at all.

Of course in reality it's a bit more complex -- as build up of water vapour (from boiling the kettle) and extra exhaled co2 (as @WelshGas) will slightly displace some Oxygen from the mix.

Most people start noticing ill effects of low oxygen at about 2500-3000 metres altitude and may start to get symptoms of altitude sickness after about 6-8hours exposure. Therefore I'd say it would be impossible to suffer severe acute hypoxia (lack of oxygen) toxicity from combustion within a van, in normal use.

 

[motacyclist]

Hi @motacyclist -- at altitude the air becomes thinner as the ambient pressure drops and it's actually the pressure of Oxygen that counts to the body, not the %, although at a given ambient pressure the two are directly related.

Simple example is that at sea level the ambient pressure of oxygen is approximately 150mmHg, which is about 21% of air (the total pressure about 760mmHg = 100%)

At Everest base camp, ambient pressure is approximately half (i.e. approximately 400mmHg) and although oxygen is still 21% of the mix, the body has approximately half the oxygen available to it (because it's the pressure not the % that matters).

What this means is that we can learn from how the body reacts at altitude to infer what may be relevant in terms of oxygen depletion in a van (due to combustion).

According to this chart (http://www.geography.hunter.cuny.edu/tbw/wc.notes/1.atmosphere/high.altitude/partial.pressure.html)

18.5% inspired oxygen (which is approximately 88% of sea level) would approximately be equivalent to 1000metres altitude -- i.e. lower than most ski resorts -- so on its own is very unlikely to be harmful in any way at all.

Of course in reality it's a bit more complex -- as build up of water vapour (from boiling the kettle) and extra exhaled co2 (as @WelshGas) will slightly displace some Oxygen from the mix.

Most people start noticing ill effects of low oxygen at about 2500-3000 metres altitude and may start to get symptoms of altitude sickness after about 6-8hours exposure. Therefore I'd say it would be impossible to suffer severe acute hypoxia (lack of oxygen) toxicity from combustion within a van, in normal use.

Thanks for the detailed explanation, it’s reassuring to know we won’t be suffocated brewing up!

 

[Borris]

Good grief, just crack open a window!

 

[larrylamb]

People worry about Carbon Monoxide in a California but that is really only a problem if a combustion source is in use that is undergoing " incomplete combustion ", yellow rather than blue flames.
When sleeping you are unlikely to have such a combustion source going within the vehicle. If you are then you are Stupid and Darwins theory is about to be invoked.
However, when sleeping, 1 or more persons, then there can be serious depletion of Oxygen levels and a consequential increase in Carbon Dioxide. This increase in Carbon Dioxide can mitigate the drop in Oxygen to a degree by making it easier to absorb sufficient Oxygen, unto a point.
If you ever wake up feeling as if you have a head full of cotton wool or an element of nasal congestion then you probably have inadequate ventilation within the vehicle.
I mean, how many people would normally sleep in your single Box room at home?

What about methane emissions?

 

[DG1]

The more I think about it, I am surprised VW didn't build in some sort of rain-proof ventilation system, for example a louvred vent somewhere that could be opened or closed as required.

 

[WelshGas]

What about methane emissions?

Depends on how many Beans have been consumed.

 

[larrylamb]

Depends on how many Beans have been consumed.

Where's Tom and his stats?

 

[WelshGas]

Where's Tom and his stats?

I'm waiting as well.

 

[Velma's Dad]

Good grief, just crack open a window!

No, keep going with the science tutorial, I'm learning a lot.

If I just wanted practical useful stuff I'd just read the Cali manual (like THAT's ever going to happen).

 

[MarkVw2017]

No, keep going with the science tutorial, I'm learning a lot.

If I just wanted practical useful stuff I'd just read the Cali manual (like THAT's ever going to happen).

I started reading it, omg, whoever wrote that has never actually owned a cali. Sucks the fun out of the cali :-0