It only goes through 1 tile-thick walls, but you generally DO NOT want the high-cap wires within your main colony anyway. Try to have all the industrial stuff, including even things like batteries outside of your core colony and insulate the walls as soon as you can. Heat WILL come and wreck you a few dozen cycles into the game unless you plan against it from the beginning.
You joke but FART HARVESTING is actually how I create water:
I farm Pufts who eat polluted air and shit slime. Above them I have Morbs who eat clean oxygen and convert it into polluted air. below them I have a floor with algae harvesters who take the slime and convert it into a little algae and half a kilo of polluted water each. With just this setup I haven't even bothered pumping in any of the starting polluted water pools---this farm along with the septic system provides so much net clean water I had to build a separate enclosed hydrogen-generator system to deal with the excess.
Below it I'm starting (and mostly failing) to build a Slickster ranch to produce crude oil and petroleum but it's a little tricky to sustain the slickster's preferred high temps.
Well assuming I can do it at their native biome, hopefully I can pump all that CO2 down there, get some petroleum out of it and not bring any of the heat up. Right now all I use crude for is as a coolant since I make plastic through drecko ranching.
Yeah I noticed that a lot of the youtube videos that pull up on specific searches end up with hour-long let's plays that barely touch on the subject in the title.
As to keeping chlorine/hydrogen out of your farms you generally wanna keep them airtight with a waterlock prior to building them. Waterlocks are more or less key for most rooms where you wanna control gas/pressure. Here's a vid on waterlocks but his example is 2 tiles high which will slow your dupes traversing it A LOT:
That's an older video and most folks nowadays make a shallower waterlock thats just 1 tile high or 2 tiles high on ONE side max. For things like a farm that will see a lot of traffic you'll want it to be no more than 1 tile high on both ends.
I tend to put airflow tiles above and below my farms and not worry too much about the extraneous gas intrusions. For oxygen farms. CO2 mushrrom farms I just put low in the base and use natural gas settling mechanics. I haven't done a balm lilly farm. That one would take a trapdoor in the ceiling and active pumping at least.
A waterlock doesn't seem like a bad idea though.
It seems like the airflow tiles help with heat venting. Still not sure if it's my imagination or if hot air rises, but it seems like hot air does rise. Maybe constrained to a radius around the heat source. If i do multiple rows of crops stacked on top of each other, the uppermost will be hotter than the lower and the middle will be hottest. Adding 1 airflow tile to the middle layer changes the heat distribution. Adding a tile to the middle and upper changes it again.
If you look at large masses of gases, i'll have places where i dig a little 2 or 3 wide tunnel straight up/down. I can create bottlenecks for gas settling with heat. Hydrogen moves more slowly through heated o2 than than cooler o2. It's a weird subtle thing. It will still eventually rise through, but it takes noticably longer to do it. The game takes relative heats into consideration.
It may be some sort of density simulation. Hotter gas is less dense so the area is less permeable since gasses don't mix. There's a curve in that math somewhere.
There is absolutely a density simulation, but the only thermal expansion that affects it is ONLY during phase changes and not in between. So in the game, cooler oxygen does NOT become more dense and sink like it should, unless you cool it enough to become liquid, then it does.
You can game the density simulation to make compressors and mass pumps using doors and automation. This game geeks me out more than factorio partly because of how the fluid dynamics interacts with game mechanics.
I love this game and have had it for awhile, put a lot of time into it, but it always feels like it falls off the cliff around day 100 or just a bit past that as I move into slime biomes and try to hold everything together.
I was being far too cautious with slime biomes. The ore purifyer doesn't even seem to be necessary. Or that useful actually, because you're not getting all the slimelung off the slime in one washing and when you put it in storage the slimelung regrows. The watertrap does seem necessary unless you want to create po2 with slime and then purify it. No heat o2 generation, but slow generation. A washstation or sink next to your slime storage IS necessary, and seems to be sufficient to keep them from getting sick.
It's like they were saying, you just go slow in slime biomes and plop down a lot of air purifiers. Remember to dig out the slime if it's in direct contact to any structure you build, because it's annoying to have little guys going to sterilize it once a day.
I haven't hit a point where I need to use slime to create water. I prefer to drain pools. But slime will create an awful lot of water. A single ice biome represents so much freaking water. I also don't use a lot of water. The Super computer takes a fair amount but that amount if static, it's not an ongoing consideration. Oxidizers don't take all that much. Reed plants do take a lot, but they're so fast growing that it seems excessive to plant more than 3-5 of them. Berry plants take some, but not very much. I wind up with lots of liquid storage containers usually and plans about making a hydrogen room eventually that I haven't made yet.
Water is almost a waste product the way I play. There's probably some critical use for it that I haven't thought about yet.
I don't -love- oxidizers because of the heat gen. Oxidier(s) + pump + filter in an enclosed space very quickly results in a very hot space. And if you try to use that o2 directly to vent your base, you'll have a very hot base before long. So you have to run that through cooling and it starts to become more trouble than it's apparently worth when the algae pumps are so effective. True, you would eventually run out of algae... but that would take quite a while.
I found a steam vent, then my top scientist and best over dup was sent to investigation, she burned to death and died... didn't notice the 275+ temperatures. Realizing I need atmos suits to check it out I refine enough ore to make the creator but can't assign anyone due to moral being too low, mean while the top of my base is a balmy 98 degree F. due to all the machines running.
Heat does indeed rise in this game, make most farms below machines or suffer. Currently looking into how to raise Moral so I can assign better jobs.
You can get mid tier without much. Barracks / Latrine or Washroom / Greatroom (plop a shitty water cooler in a mess hall and boom) will get you around 14ish morale.
For the top 2 tiers it looks like you need plastics, really. Because you'll need personal bedrooms and amenities like the espresso machine and snazzy suits and stuff.
But you could also just invest in massage parlors. They'll creep up to your set point and then take a day off getting their bits jiggled and creep back down. 1% sickness and 99% stress are the only numbers that matter.
You'll absolutely need a waterlock demarcating your base from any slime biome, or ANY volume where you want to restrict gas flow. Even you have atmo suits, you want a waterlock between your hab area and everything else. There's no other total airlock mechanism in the game until you get transit tubes.
Another thing you can do with waterlocks is to use airflow tiles on the sides to prevent leaking, this way you won't have to refill them over time. Because the game implements the liquid-impermeability of the airflow tiles by adding a sort of repulsion field on them so that the liquid can't touch the tiles, it'll form like a bubble in the middle of the waterlock: