Oxygen low warning

[EliteForceQc]

I need help to understand:

The atmosphere in my base was (21% oxygen, 6% CO2, rest nitrogen) in 65 Kps
Everything fine for many many days in game. And at some point I got the "Oxygen Low" warning (from my suit when open the helmet inside th base). So I bumb the oxygen to 23% and everything fine for many days.

Then "Oxygen low" came back .. so I bump oxygen at 25% .. again everthing fine for many days in game .. Then "oxygen low" came back .. and so on

Now I'm at 27% oxygen and just got the "oxygen low" warning ...

What is going on ?

[God, owner of the Universe]

If the pressure was indeed (almost exactly) the same, then something fishy is going on - but that could be your lungs being damaged. Damaged lung = less capacity to take in oxygen.

You can look in the world.xml file of your savegame if you can see lung damage. Don't know how/where exactly, maybe searching for "lung" will get you there.

Your lungs take damage from breathing in toxic stuff, air below 0°C or above 50°C, or possibly from being in the vacuum for too long, IDK.

You could eat the pill just now to see if that changes your observations. If it does ... it was lung damage.

[EliteForceQc]

Make sens about lung damage .. Ill take the pill and look if this resolve the problem.

Thank you for the answer.

[JeanDeaux]

I know that 22% Oxygen is the minimum threshold in game before you start to take lung damage. Since you're breathing in O2 it makes sense that it grows thinner over a few days if you don't have an automated method of replenishing what you're breathing in.

Any chance the warning at 27% was simply a coincidence that your suits O2 tank was low? Do you turn off your suit while you're in the hab or leave it running?

[EliteForceQc]

Originally posted by JeanDeaux:

I know that 22% Oxygen is the minimum threshold in game before you start to take lung damage. Since you're breathing in O2 it makes sense that it grows thinner over a few days if you don't have an automated method of replenishing what you're breathing in.

Any chance the warning at 27% was simply a coincidence that your suits O2 tank was low? Do you turn off your suit while you're in the hab or leave it running?

I always look a the atmosphere in the base (pressure, temperature and %). Having nothing else to do anyways. I always turn off my suit once inside my base.

I really think is a lung damage. Ill always do that noobies mistake to go in the SAS forgetting to close my helmet when i'm going outside. I think I got lung damage over time doing so.

Ill test the pill when ill be back from job tonight.

[Ketrix]

I just wanted to point out that it's not the %-ratio of oxygen that matters. It's the partial pressure of the oxygen that is important.

Partial pressure = Total Pressure * RatioGasType

Earth air has 21kPa partial pressure of Oxygen. A base with 21% oxygen and 65 kPa pressure only has 13.7 kPa partial pressure of Oxygen, almost half, so it's not strange that just a little bit of lung damage is enough to cause breathing problems. To get an earth like Oxygen amount a 32% (21/65) ratio would be necessary.

The Cryo Tube can also be used for healing. The cold nitrogen is just for reviving dead people, normal base air (from a passive vent) is good enough to heal those who are alive. The Tube is perfectly safe, but it's a nasty experience to use one for the first time.

[ждун]

Well this mix is on the edge already even with healthy lungs. 21% oxygen @ 65 kpA this is like living on mount everest. Increase the pressure or oxygen ratio. With 21% oxygen you should have at least 80 kpa, better 101,3 kpa to have normal earth conditions at sea level if that is your intention.

Why are you using a gas mix at all? Youre shooting yourself in the leg overcomplicating things with no reason really. I suggest using pure oxygen atmosphere at low pressure for living space. And mostly pure CO2 atmosphere for the greenhouse. This makes the whole setup much simpler and also saves resources. In pure oxygen atmosphere you need much less pressure for breathing. You have no any advantage from using complex gas mixes in your base.

[God, owner of the Universe]

The "advantage" of a complex mix (e.g. 20%, 78%, 2%) would be realism / roleplaying. And who knows, maybe RocketWerkz will eventually be less lenient when it comes to breathable atmosphere (I'm hoping for it).

[ждун]

Originally posted by Ketrix:

I just wanted to point out that it's not the %-ratio of oxygen that matters. It's the partial pressure of the oxygen that is important.

Partial pressure = Total Pressure * RatioGasType

that is correct and important to understand.

Originally posted by Ketrix:

To get an earth like Oxygen amount

I never understood the reason why many people are seeking earth like air mix? Most of it is just useless ballast that only overcomplicates things. There is absolutely no reason to have an earth like gas mix. Pure oxygen at low pressure is much better and simpler to manage.

[ждун]

Originally posted by God, owner of the Universe:

The "advantage" of a complex mix (e.g. 20%, 78%, 2%) would be realism / roleplaying.

In fact this is unrealistic. In real space ships they use pure oxygen and on a real mars base they will also most likely use pure oxygen. The only valid reason to use earth-like air would be for safety reasons (danger of fire when flameable gases are present too). But this is something you can actually easily avoid.

[God, owner of the Universe]

Originally posted by ждун:

In fact this is unrealistic. In real space ships they use pure oxygen and on a real mars base they will also most likely use pure oxygen.

In fact, I didn't know this. More material: https://space.stackexchange.com/questions/5690/why-is-the-breathing-atmosphere-of-the-iss-a-standard-atmosphere-at-1-atm-conta

So, ISS uses kinda what I said, but the reasons are almost not related to health, and space ships indeed use oxygen.

But how can fires "easily" be avoided? What do you mean?

[ждун]

just don't release volatiles inside the base. Or if you can't avoid it for some reason, avoid using welder inside the base while oxygen and volatiles are both present in the air. Or if you can't avoid this too, perhaps you could build a single filtration unit removing volatiles. The air becomes explosive when you have oxygen and vloatiles ratio both over 5%. It ignites when temperature reaches more then 300 °C or when you use a welder.

In reality pure oxygen atmosphere can be dangerous in the event of fire. You would have a much more intense fire. In reality fires can happen for example because of short cirquits in the cabling or electronic devices due to moisture condensate. But in the game this can't happen, and the only way to catch the base on fire is basically having an explosive gas mix which you ignite with the welder.

[JeanDeaux]

Whew, okay, he was talking about "in game" only. I was worried he was bringing in RL discussion points.

[ждун]

The advantages of using pure oxygen atmosphere for living/working space are obvious.

No need for maintaining certain mix ratio, which involves additional devices in more or less complex setups, which requires additional power and resources to build. Probably also some programming.

Less pressure required inside the base, hence less pressure difference with the outside unless you are on high pressure planet such as venus. This reduces the risk of bursting walls and speeds up airlocks.

With less pressure air conditioning is much faster and requires less power.

No need to collect large amounts of nitrogen or other gases.

For the greenhouse it makes sence to have mostly pure CO2 atmosphere perhaps with some additive gases if particular plants require them. Plants grow better in special atmosphrere. When they are not thriving, this is mostly either due to not optimal atmosphere or light conditions. The oxygen produced by plants can be removed with simple filtration unit and used in the living space. However you would have to keep the helmet closed in a pure CO2 greenhouse.

[God, owner of the Universe]

Well, I thought you meant IRL when you said that fires can actually easily be avoided.

[Jethro Sigwilder]

Originally posted by Ketrix:

I just wanted to point out that it's not the %-ratio of oxygen that matters. It's the partial pressure of the oxygen that is important.

Partial pressure = Total Pressure * RatioGasType

Earth air has 21kPa partial pressure of Oxygen. A base with 21% oxygen and 65 kPa pressure only has 13.7 kPa partial pressure of Oxygen, almost half, so it's not strange that just a little bit of lung damage is enough to cause breathing problems. To get an earth like Oxygen amount a 32% (21/65) ratio would be necessary.

I learned so much from this one post. The phase changing has been really kicking my behind, and I've been very slowly learning about those features, but this bit of info is going to change how I monitor atmospheres in my base. Nearly 250 hours in, and honestly, I've just been winging it, so far. Every near (or actual) death experience has been teaching about things to avoid, but very little about why exactly I should be avoiding it, let alone what I actually should be aiming for.

Thanks!