Did the conditions for breathable air change?

[Bags77]

I have my normal air mixture of around 20% oxygen, 10% CO2 and 70% Nitrogen at around 100kpa. Never had an issue with it in the past.
Now i get a "Low Oxygen" warning when taking off the helmet. Did something change? Do we now need a higher concentration of Oxygen?

[Bags77]

Strange, another room with about 21% Oxygen works fine. I may be right at the border of breathable then. Will increase the Oxygen percentage slightly and see if that fixes the issue everywhere

[JeanDeaux]

I know there was an Atmospherics update released a few weeks/months back that did have an affect on our atmosphere. The devs even warned us about making sure we had a nitrogen mix in the air to avoid some problems prior to that release. It wouldn't surprise me at all to find we'll need a minimum O2 level requirement without taking any health damage.

[Rigben]

I use 30% oxygen 70% nitrogen mix and currently just release my waste co2 (end up with about 1.5-2.5% co2 in the air) along with a portable tray of mushrooms. Myself and my plants never have any issues at those levels. I would say by your info maybe use 25% o2 to allow for a safety net.

[Caver451]

Maybe it is because I am on "easy mode", but I can breathe air at over 50% CO2 and less than 40% O2, a situation which would be quickly fatal in real life. CO2 concentrations over 10% are quickly fatal, and can cause permanent organ damage even if you don't die. And that is even with the Oxygen levels at over twice normal levels.

Oxygen concentrations lower than 16.5% are considered dangerous as well, and I could swear I remember having no issues in a room with 10% O2 in-game...

The more I read on this topic, the more it becomes obvious that the "real world" is a lot more complicated than we normally think. If you want your eyes to glaze over, tried reading about plant respiration. Goodness!

[ждун]

Pressure also matters. Its the mol amount of oxygen per volume that matters, not the percentage.

In example you can breath pure oxygen atosphere already at 20kPA pressure, but when you use an air mix you will need higher pressure. You could also breath air with 10% oxygen but you would need high air pressure.

So I guess your pressure is too low thats why 20% oxygen is simply not enough. Its like being on mount everest. At 8800 meters altitude there is also 21% oxygen, but due to lower air pressure you are getting short on oxygen, breath faster and some people cannot be there without oxygen supply.

To be honest, I don't know why many people are using an air mix at all.
It is just making everything more complicated. Why not pressurising with pure oxygen? It makes much simpler setup. No need to gather nitrogen. No need for maintaining propper air mix, simply filter out all gases but oxygen. Due to lower pressure requirement you also need less heating/cooling capacity, hence less energy to run the whole base.

Keep things simple, it is compicated enough, don't make it more complicated as it needs to be.

What about my greenhouse you will maybe ask...

Well, I suggest having an airlock separated atmosphere for the greenhouse and keep things simple there too supplying it with pure CO2 atmosphere. At least the main food plants grow well in pure CO2 atmosphere. If you really want to grow plants that require some other gases make a separated greenhouse for them. But to be honest there is also no reason to grow those plants, as all you need from plants is food and maybe for oxygen generation. Potatoes, tomatoes and fern is sufficient for this purpose so you can keep things simple. It is less complicated to build an airlock then maintaining a base with mixed air atmosphere that is sufficient for breathing and growing plants.

[Rigben]

Originally posted by ждун:

Pressure also matters. Its the mol amount of oxygen per volume that matters, not the percentage.

In example you can breath pure oxygen atosphere already at 20kPA pressure, but when you use an air mix you will need higher pressure. You could also breath air with 10% oxygen but you would need high air pressure.

So I guess your pressure is too low thats why 20% oxygen is simply not enough. Its like being on mount everest. At 8800 meters altitude there is also 21% oxygen, but due to lower air pressure you are getting short on oxygen, breath faster and some people cannot be there without oxygen supply.

To be honest, I don't know why many people are using an air mix at all.
It is just making everything more complicated. Why not pressurising with pure oxygen? It makes much simpler setup. No need to gather nitrogen. No need for maintaining propper air mix, simply filter out all gases but oxygen. Due to lower pressure requirement you also need less heating/cooling capacity, hence less energy to run the whole base.

Keep things simple, it is compicated enough, don't make it more complicated as it needs to be.

What about my greenhouse you will maybe ask...

Well, I suggest having an airlock separated atmosphere for the greenhouse and keep things simple there too supplying it with pure CO2 atmosphere. At least the main food plants grow well in pure CO2 atmosphere. If you really want to grow plants that require some other gases make a separated greenhouse for them. But to be honest there is also no reason to grow those plants, as all you need from plants is food and maybe for oxygen generation. Potatoes, tomatoes and fern is sufficient for this purpose so you can keep things simple. It is less complicated to build an airlock then maintaining a base with mixed air atmosphere that is sufficient for breathing and growing plants.

Never use pure oxygen for your bases atmo unless your base is literally just a safe spot. Even a heater turning on or a microwave can ignite pure oxygen.. trust me I know..

[ждун]

really? never happened to me.

youre sure about it? In stationeers oxygen alone seems not to be burning, otherwise you could use pure oxygen to fuel the furnace. I have used all kind of electrical equipment in pure oxygen pressurised base. Microwaves, Heaters, Atmospherics, Computers, IC chips. I have heated pure oxygen in tanks to more then 1500 degrees, nothing happened to it. In stationeers it can only become dangerous when you release volatiles into it up to 5% volume. However it will also make an explosive air mix with 20% oxygen too if you add volatiles.

So just don't use gas welder inside as it leaks volatiles when used and use electric welder instead.

[Rigben]

Originally posted by ждун:

really? never happened to me.

youre sure about it? In stationeers oxygen alone seems not to be burning, otherwise you could use pure oxygen to fuel the furnace. I have used all kind of electrical equipment in pure oxygen pressurised base. Microwaves, Heaters, Atmospherics, Computers, IC chips. I have heated pure oxygen in tanks to more then 1500 degrees, nothing happened to it. In stationeers it can only become dangerous when you release volatiles into it up to 5% volume. However it will also make an explosive air mix with 20% oxygen too if you add volatiles.

So just don't use gas welder inside as it leaks volatiles when used and use electric welder instead.

Could have been some other influencers I did not notice, I just know I have had fires start from various things before I started mixing my atmo. Heater / microwave / assemblers and such have all been able to trigger a fire in previous runs. This was also before I got a handle on pressures though so for all I know a blew a pipe that put other things in the air. I never really investigated these disasters because it always ended in my base being blown up so I would reset.

[ждун]

Mixing air will not save you from such accidents.
The air will ignite when it contains at least 5% oxygen AND 5% volatiles and the temperature reaches about 300 °C or by a spark or open flame. So even with an air mix that contains only 20% oxygen you may still blow up your base when you add certain amount of volatiles.

Perhaps your atmosphere was contaminated with volatiles or possibly NO2 by that broken pipe. It happened to me once in very beginning. First I didn't realized what caused the fire, but later I figured that out by tests. It was because I used a gas welder inside. I was not aware that it was releasing some of its fuel mix which contains volatiles. At certain point the amount of volatiles in the air reached 5% and next time I used the welder - boom.

With a bit more experience I am whatching the atmosphere inside. It is also easily possible to build an alert system that will trigger alarm when volatiles or tixic gases are present in the air. It could also autmatically shut down power supply in case of explosive gas mix inside and one could also build a mechanical valve to flush dirty air in case of such emergency.

In pure oxygen atmosphere I never had a fire inside the base desipite excessive using of all kinds of electronic devices. I set an array of atmospheric filters that pull out any other gas then oxygen and pressure control pump that pumps in fresh oxygen maintaining 30kPA pressure. 30kPA pure oxygen is sufficient for breathing.

Having a pure oxygen atmosphere has a number of advantages over an air mix. As you only need 30 kPA of pressure for breathing you have much less mols of gas inside the base. That means you need less gas in total. No need to gather nitrogen. No need to maintain propper gas mix and run a mixer, pumps and logic for them. Less energy required for maintaining the right gas mix and also because there is less gas inside much less energy is required for conditioning. Conditioning with less mols is also faster. Perhaps you don't need complex conditioning systems, as simple passive cooling/warming may already be sufficient where with an air mix under higher pressure you may need an air conditioning unit, which can eat lots of power. An array of 3 filter units for cleaning the air from any unwanted gas consume very little power compared to air conditioner.

[JeanDeaux]

Originally posted by ждун:

really? never happened to me.

I tried to find it but it was stated by the dev's a long time ago. They warned us that an update was coming and bases with 100% oxygen would be dangerous to operate and that we should start now making sure that they included a Nitrogen mix to reduce that danger threshold. I don't know if that referenced update is out now, if it's working as intended, etc... but they took the time to mention it so I'm taking the warning to heart that if not already, it's going to be an issue.

I too used to run every pocket of atmosphere with just O2 and CO2 where plants were mixed, didn't bother with any other gasses. I even use O2 for my jetpack fuel just because I don't want to bother with storing additional gasses. I haven't yet seen any negative affects from running high O2 levels specifically, but I have become accustom to adding the Nitrogen to the atmosphere in heed of this warning.

[ждун]

@JEanDeaux well bases with pure oxygen can be dangerous under certain conditions now already. If you have say pipes that contain volatiles in the base and they break or if you use a gas welder inside, or anything that can release volatiles in uncontrallable way, then you may create an explosive gas mix inside and it can ignite by a wall heater or a light switch. But if you know it, it can be avoided.

But ive done some tests just recentely igniting fuel in a gas tank for later use as heat buffer for the furnace. The gas mix inside a tank becomes flamable when there is at least 5% oxygen and at least 5% volatiles and it ignites at about 300 °C. Once it ignites, it will burn until either volatiles or oxygen is completely burned. In a tank that contains pure volatiles or pure oxygen the gas can be heated beyond 1500 °C safely. It won't ignite, only a mix of oxygen and volatiles. So if you can exclude contamination with volatiles, you should be safe.

[JeanDeaux]

Well make up my mind, are you saying it's an issue or aren't you? You seem to be playing both sides here from my interpretation.