Guide to Atmospherics

This is the Guide to Atmospherics. When properly initialized, Atmosia can keep the station aired-up through nearly any emergency. Improperly initialized, it's a waste of space at best and an outright fire hazard at worst.

If you're new to the job, feel free to jump straight to the how to set up Atmos -section. If you're ready to really learn about the atmospheric system, read on. By reading this guide you will learn how to transform Atmos from a waste of space to an actually useful addition. We will go through all kinds of theory, so this may be tough, but it will also ensure you know exactly how and more importantly why Atmos works the way it does, making you ready for all kinds of situations.

The city of pipes and air, a peaceful place often left to its automatic work... But not today, thanks to you!

Other Atmospherics related information:

Atmospherics items

The Gases and Their Functions

Let's start with some theory about the gases. Below are the different gases that can be found in game.

O₂

Oxygen. All humans, pets and lizardpeople need more than 16 kPa of oxygen in the air or internals to breathe. Any less and the creature starts to suffocate.

It is required to oxidize a plasma fire. A room with 100% plasma will not burn. More oxygen causes plasma fires to increase in heat and size. Oxygen mixed suddenly with heated plasma causes explosions. See Temperature.

Oxygen is an invisible gas. To detect it, use your PDA or a wall mounted Air Alarm. Oxygen canisters are marked in blue. Emergency Oxygen Tanks, filled with about 300 kPa, spawn in your emergency Internals Box. Larger Oxygen Tanks are in Emergency Lockers all across ship, which start with about 600 kPa.

N₂

Nitrogen. Soaks up heat in the air, and lowers the temperature of a fire. By association, it can very quickly lower the temperature of a fiery rupture to the point where the flames self-extinguish.

Proof of this can be seen if you go down to the incinerator with a can of burnmix, and a can of 20% burnmix and 80% N2. The N2 contaminated fire will not burn nearly as hot or as well. This is why the Toxins guide recommends opening up a can of N2 to the air; it can and will save your life if there's a rupture.

Due to the vastly higher heat capacity, N2 is incredibly better at stopping fires: in 100 kPa of N2/O2 80/20 and 100 kPa of 100 % O2, the N2/O2 is effectively 12200 kPa as opposed to 100 kPa in terms of soaking up heat and it doesn't allow the fire to grow in size as quickly, the combination of which can even lead to non-permanent ignition sources being snuffed out by themselves.

Can be found in Atmospherics in red canisters.

Air

A 1/5 gasmix of O2 and N2 (20% O2, 80% N2). The station is filled with this.

Air in SS13 can be seen, strangely enough, as a 'watered down'-O2, with N2 being the water. Optimal atmospheric pressure for humans is 101.3 kPa. Due to the minimum of 16 kPa of O2, the pressure of 101.3 kPa cannot be changed too much without the situation becoming excessively lethal. Under 16 % oxygen? You start dying. Under 90 kPa due to fire from a while ago? You start dying. Be mindful of this.

Air canisters, marked in white, can be found in emergency storages.

CO₂

Carbon Dioxide. An invisible, heavy gas, CO2 is one of the first and fastest gases the scrubbers suck out of the air. Humans produce very small amounts of CO2 through breathing.

It chokes people effectively and quickly, and if you can be bothered to set the alarms up, will result in a invisible room that kills those in it. Takes some setup and can be very, very annoying. Causes people to gasp at low levels.

Can be found in Atmospherics in black canisters.

N₂O

Nitrous Oxide, a.k.a. Sleeping Agent. A white-flecked gas.

Makes you laugh at low doses and at higher ones puts you to sleep. Scrubbers don't deal with it too well and portable scrubbers just choke on it. If using this as a sleep gas mix do not forget to mix in at least 16 kPa of O2, or you will suffocate someone.

Can be found in Atmospherics in red canisters with a white stripe on them.

Plasma

Toxins. The one truly flammable gas on the station, plasma is purple, and highly toxic.

Of note is the fact that in the presence of any oxygen at high pressures, Plasma pumped into air, and Burn Mix (O2 and Plasma), can and will spontaneously ignite in an open area at high pressures.

Physical Characteristics of Gases

Ideal gas law: PV = nRT

Where R (ideal, or universal, gas constant) = 8, the following are linked by this equation. Sadly, without either Volume or Moles, it's not useful in game and is here for the theory.

Pressure (P): Measured in kPa, kiloPascals, Pressure is lethal above 750 kPa's. A pressure in a room above 1000 kPa's necessitates internals to breathe properly.

Volume (V): Another unseen variable, Volume is how much the area/canister/tank or piped tank has space inside it. This helps dictate how much gas it can hold. Volume is essentially the 'mole divider' when converting between a canister/air pump to your tank; having a higher volume essentially makes the tank that much more efficient, proportionally, so an Extended Emergency Oxygen Tank has twice the contained air per kPa in comparison to a regular Emergency Oxygen Tank.

• The small, blue Emergency Oxygen tanks have volume 3.
• The yellow Extended Emergency Oxygen tanks have volume 6.
• The big, blue or red Oxygen Tanks and orange Plasma Tanks have volume 70.
• Lockers or a coffins have volume 200.
• The huge canisters have volume 1000.
• Tiles of space have volume 2500.
• Gas and volume pumps have volume 200 on each side.
• Passive gates have volume 200 on each side.
• All pipes have volume 70 or 105 (manifold only).
• Vents & scrubbers have volume 200.
• Portable pumps have volume 1000.
• Portable scrubbers have volume 750.
• Unmovable pressure tanks have volume 10000.
• Huge scrubbers have volume 50000.
• Manual and digital valves have no volume.
• Heat exchangers have volume 200.
• Gas filters have volume 200 on each side.
• Gas mixers have volume 200 on input sides and 300 on output side.

Moles (n): While not a variable that can be seen, Moles are the amount of particles of a gas in the air. It is moles that cause odd effects with a certain chemical. As it dumps so many moles to a tile, to keep the pressure acceptable, the moles have to be very, very cold, causing the infectious effect.

Temperature (T): Measures in K, Kelvin, Temperature above 360 K and below 260 K causes burn damage to humans. Bomb making usually relies on a temperature at or in excess of 90 000 K. Canisters rupture when the air surrounding them is over 1550 K.

Heat Capacity: A gasmix has heat capacity, and it is calculated by taking into account the quantity of all of the gases in the air and their specific heat. Oxygen has a specific heat of around 20, CO2 has 30, and N2 has 300. When you factor in the normal 70% N2 it leaves you with a very high specific heat. The higher the specific heat, the more energy required to heat up the mixture, meaning that with an air mix vs. pure O2 mix, it takes much more energy to heat the air than the O2, and the increase in energy required also decreases how much the fire spreads. Simply slowing it down means that heat energy will be 'soaked up' by the air instead of super-heating everything extremely quickly.

• O2: 20
• CO2: 30
• N2O: 40
• Plasma: 200
• Air: 250
• N2: 300

Fire: An effect caused by burning plasma, fire comes in two different forms of hotspot. It causes massive burn damage, and a strong fire will not be stopped by standard firesuits. Plumbing N2 into a room might work, but heavy firefighting is not the point of this section. Fire will ignite any form of combustibles in near tiles. Sufficiently hot fires use less oxygen as they rise in temperature. This is due to the fact that fires remove X plasma and X*(1.4-Y, Y< or = 1) oxygen. X CO2 is produced. Ideal Burnmix is: higher O2 than plasma for really cold ones, such as open air small plasma usage, with a consistent decrease based off of temperature until you reach 28.57% O2. In general, 30% O2 is a good mark for N2 less fires.

Atmospherics Layout

A wise Atmos Tech once said: "just stare at the pipes until you get it."

"Simplified" picture of the Atmospherics pipe system. Yellow circles represent filters and the lightbrown circle represents the mixer.

Here are two pictures of the atmospheric pipe system. Right one is a "simplified" version of the left picture. Yellow circles representing the filters which filter out a certain gas from the Waste In -gasmix. The light yellow circle near the lower middle represents the mixer which mixes two gases into one (N2 and O2 into a breathable air mix).

Atmospherics is pretty simple, but the pipe layout makes it slightly confusing for the untrained eye.

There are 4 major pipe "loops":

• The dark blue pipe loop is the distribution loop. It sends air to all the vents on the station for the crew to breathe.
• The cyan air mix pipe loop, which is specialized to mix and provide the air mix to the distribution loop, and is used to fill air pumps outside the front door of Atmospherics.
• The red/green pipe loop, which retrieves the gas in the station via the air scrubbers (red loop) and passes them through a set of filters (green loop).
• The yellow pipe loop, internal to Atmospherics, which is used for custom gas mixes that can be fed into the canister charging station in the middle of atmospherics, or fed into the mixing tank.

The tanks (the small rooms in space just outside of Atmos) of the station's atmospherics network, unlike in the rest of the station, are rooms filled with very high pressure of the appropriate gas. The output of these rooms are controlled by their respective Supply Control Computer, an on/off valve, and an output pump for each loop. Note that these rooms can be depleted, especially if someone makes a hole in a tank's external wall.

To understand how the breatheable air mix is mixed, try following these steps and looking at the map at the same time, it starts on the south end of Atmospherics, like so:

1. The gasses are pumped through the cyan tubes from their respective tanks (N2, O2).
2. They are mixed in the air tank (Air) to a 1/5 mix of O2 and N2.
3. The breathable gas is then pumped through the cyan loop to the north of Atmospherics.
4. And finally it's pumped into the dark blue distro loop and out to the station for everyone to breathe.

Next let's make up an example situation to see how the waste system works in action:

1. Scientist Bill messes up and fills the Toxins Lab with plasma but fortunately manages to evacuate the room safely.
2. Being an otherwise ideal situation Atmos-wise, the Toxins Lab's air scrubbers have been set to filter out all hazardous gases (they're not set by default, this has to be done through the Air Alarm manually or by asking the AI to do it) and plasma starts to get sucked through the scrubber into the waste pipes.
3. The plasma arrives to the Waste In -loop (the red pipe loop) at Atmos. It travels south through the pipes, its first stop being the N2 Filter.
4. If there was any Nitrogen in the waste gas, it would get filtered out here, and the rest of the gas continues its journey through the waste loop, same thing happening at every filter.
5. The plasma finally reaches the Plasma Filter.
6. Here the plasma gets extracted from the waste gas and pushed into the big plasma tank-room outside the windows.
7. The plasma stays in the room until someone decides to pump it out.
8. Scientist Bill by now notices that the Toxins Lab has no plasma anymore and is able to safely continue his work. Yay!

Setting Up Atmospherics

It's about time we stop with the theory and get down to business. The two machines at the top can dispense infinite pipes, and your wrench can disconnect and connect pipes. Remember, you cannot disconnect pumps when they are on.

The dumbass-version of the Atmos pipe system. See the steps what each colored circle means.

Next up is a very simple step by step guide how to set up the Atmospherics pipe system to be (nearly) as efficient as possible. Note that this is only one style how to set up the pipes, there are many ways and they all have their own pros and cons!

1. Get at least two Volume Pumps from the Pipe Dispenser at the north side of Atmos.
2. Replace the green circled normal pumps with volume pumps, making the waste gas -system >100x more efficient. We want the waste gas sucked out as soon as possible!
3. Replace the blue circled normal pumps with volume pumps as well, but notice; there are risks involved and all of them are covered at the pros and cons -section below.
4. Set all red circled filters to maximum pressure (4500 kPa) so waste gas will actually be moved.
5. Go through the N2, O2 and Air -computers beside the south wall and set their output to maximum (5066.25 kPa).

• Pros and cons of this setup:

+ Quick toxin filtering. In case of a toxin leak, waste gas will be sucked out quickly (if the area's air alarms are set to filter out all the toxins, that is, by default they are NOT filtering anything).

+ Quick repressurization. In case of a breach, air will be poured out with a nice pace, helping you re-pressurize the room quicker after the breach is fixed.

+ No pipe sabotaging. With this setup, the grifflords cannot fuck up pipes in the maintenance tunnels. In a room with the default 101.3 kPa atmospheric pressure, pipes with more than 303.9 kPa pressure cannot be unwrenched.

- Air Alarm sabotages. The station is more vulnerable for sabotage through air alarms. Someone can quite easily hack an air alarm somewhere and set the vents to push out air at maximum pressure, resulting in overpressurization.

- Space wind. In case of a breach, until the hole is fixed, you'll probably spend a small while fighting against the huge air current, a.k.a. "space wind", if you don't switch the vents off during the repair. This is mostly just annoying.

- Very slow distro pipe manipulating. If you'd suddenly get a need to modify any of the distro pipes, you'd need to lower the pressure to under 303.9 kPa, which could take a long time.

A little safer, but not as efficient, way of setting up the system is leaving the blue circled normal pumps completely alone or maybe raising the pressure to 315 kPa. This pressure is enough for quick pipe manipulating and for a sufficient air distribution.

Done correctly, Atmosia should be pumping good air just faster than it's lost, and draining bad air away as fast as the traitors can set it on fire or alternatively draining good air away as fast as a malf AI can syphon it. You can go kick back in the bar like a boss, and wait for the inevitable minor station damage and cries of "Call the shuttle!" on the radio from folks who don't even know it ain't a big deal.

After the Work is Done

There is a short list of things which fall under your stead:

• First and by far most important: make sure pipes don't get broken and if they do, fix them.
• Go around swiping your ID on Air Alarms, setting Plasma and N2O to filter, and then re-swiping to lock it. You can ask the AI to do this as well, and probably should.
• Fill all the air pumps with air using a volume pump (more air pumps can be found from the locker room).
• Make extreme extended oxygen tanks for internals use (instructions below).

1. Go to the red lockers, get a hard hat, gas mask and everything else that might be of use. Remember that you need both a fire suit and a hard hat to be resistant to weak fires. One will be useless without the other.
2. Go grab the Fire Axe from the wall mount and hide it somewhere the chucklefucks won't get it and go killing. DON'T take it with you and go walking through the hallways trying to look like a badass, you'll be the prime target of any antagonist/griffon who needs an efficient weapon.

• Least importantly, maintain the disposals system. You can generate pipes, but it needs welding and is generally a pain in the ass. You can also make fun slides, though.

Optimizing Internals

• On a basic view, a 16 kPa minimum O2 requirement in internals. Pure O2 is theoretically toxic in real life, but has no representation for this in code, and takes a while to be really dangerous anyway (they use it to treat certain diseases, for example), and thus using a tank filled with air for internals is fairly inefficient.
• Cold O2 has more moles per kPa, and because people breathe in moles, and filling tanks usefully for internals is largely capped by the 1000 kPa release pressure, means cooling your O2 before using it in internals is important! Cooled down O2, such as from a freezer-ed canister, is the most efficient way to set up internals. Cooling it below 264 K will result in icicles inside in your lungs, though!
• If you need to empty an internal tank to make space for better, colder O2, you can use an Air Pump. Set it to "pump in" and "turn on" then "off" with the tank inside it, making it completely empty, thus allowing you to refill the tank more effectively.

Your Very Own Customized Mix

To create a custom mix of gas, turn on the output of the supply control computers, open the manual valves, and turn the output of the pump to what you wish it to be. The gas will travel through the orange pipes into the mixing chamber. The gas mix is pumped into the mixing chamber via a pump north of the orange loop.

The mix obtained can then be pumped into the distribution and filtering loop or used to fill canisters. Remember to turn off the pump between the yellow and red pipe network or your custom mix will just go into the red waste loop.

Fun Projects

• The Atmospherics system is far from optimal, and we're talking about just the pipe configuration! Break out that wrench and start experimenting (just make sure you know what's what)!
• Extremely high temperature gases (like those from a panic siphoned fire) can really clog the waste loop. Could you do something to correct that?
• No one uses the ports outside of the 'refilling' station, but that doesn't mean that functionality can't be added onto them!
• The wall section that looks like the letter 'I' can be dismantled if you need more working space for pipes.
• Don't count out the grated window areas, they can be a great (har har) way to utilize the vacuum of space without an EVA suit.
• Speaking of EVA suits, your engineering buddies can potentially help you with anything you might want to do in space, be it adding or modifying pipes. Watch the hilarity as that incompetent engineer fumbles with the huge crate of pipes he dragged out into space for you!
• The main cargo area inside Cargo has a laughably small number of vents, and how many times have those dumb dumbs sent the shuttle off while the doors are open?
• The brigs distribution system is set up to be potentially independent of the rest of the stations distribution loop, maybe other places can be set up like this as well?
• The mining station doesn't have air recycling. Very long rounds might make this a problem for any miners working there.

The Less Well Known Hazards of Gases

• Any gas at pressure over 1000 kPa will cause you to start suffocating as in a vacuum. You can just use internals, though.
• N2O is invisible at low pressures. If you start giggling, put on your internals to avoid passing out.
• Any gas can displace O2, and less than 16 (also useful for optimizing internals) kPa of oxygen starts the Oxyloss. CO2 can be removed with the scrubbers, but to get rid of N2 simply apply some way of removing gas from the air and adding O2. My personal favorite is 2 air pumps, 3 connectors and a Air Filter and a canister: 1 pump draws in, goes through the connection and filters N2 into the canister, and the rest to the other pump, which expels it. Can also be used for N2O which is only sluggishly scrubbed otherwise.
• Pressure's above 750 kPa do 10 DPS + 5 DPS for every extra 375 kPa above that mark, rounded off. Space suits completely block it all, but there is no other defence.

Useful Atmos Trivia

• Using H/E pipes in space you can cool things down to a very low temperature very quickly. By making a cross with two off them you can have two on one tile, which is known as 'sequesteral' cooling.
• Air Filters on currently burning mixes can siphon out heated but PURE O2 and Plasma. Do the O2 first then the plasma, as there is less O2 in a fire and thus it functions faster. This (and H/E) allow you to reach really obscene temperatures.
• Air Filters and H/E allow you to expose gases to the heat of fires (or their CO2 product) but keep/make them pure, allowing for hot N2O or similar.
• Using a small starter flame/heater you can have in pipe combustion.
• Canister bombs are heated Plasma in a canister, with a O2 tank placed in the canister, and then open the valve between them. You will also need to run very, very fast.
• The gas diverted by an air filter has no maximum pressure, and can therefore reach an insane amount. For example, you can filter out the oxygen into one sealed pipe and it will keep rising.
• Pipes at around 300 kPa pressure can be unwrenched, however, devices such as pumps and filters don't really 'hold' pressure and can be unwrenched at any time (assuming they're off)!
• Gas pumps are for precise pressure control, volumetric pumps are for really fast pumping, and passive gates are for having 'one way' manual valves.

Being a Traitorous Scum

Or: How to get the AI lynched; How to call the shuttle as Atmos Tech, step-by-step:

1. Open valves connected to harmful gas you want to add to the station.
2. Set pumps to the distribution loop to maximum pressure output (4500 kPa).
3. Set filters to not filter harmful gasses you want to add to the station OR set the waste-in pump to 0 kPa (but leave it on to confuse the crew).
4. Open valve from custom mix chamber.
5. Turn on pump leading to distribution loop.
6. Wait for vents to slowly kick out your deathgas mix as regular atmos drains out through the inevitable hull breaches (alternatively turn off pressure checks on air alarms' vents to speed things up).
7. If you need to kill someone for your objective, and you want to be more proactive, the Fire Axe mounted in the wall is surprisingly effective. Just don't leave it lying around, because it's one of only two on the station.

To hurry this process up, you can set the air vents at local control panels to maximum output pressure. Not doing so gives the AI and Atmos Techs more time to notice what you've done and shut it off before it takes effect.

A faster process for achieving the same result is to do the following:

1. Disconnect, change the direction of, and reconnect the pump that feeds from the air mix to the mix tank in the north-eastern room of atmosia.
2. Open the valves for your deathgas mixture of choice.
3. Power on and max the pressure on every pump in the mix pipes (yellow pipes) from the storage tanks out to the station output (blue pipes).

This simply means that instead of the air mix being put into the mix tank as it normally does, the air mix (which may or may not contain death gasses) is fed into the station output.

Crafty atmos traitors will want to cut cameras, replace pumps with pipes, use tricky pipe configurations to avoid the AI interfering or the detective trying to fix it and make a hole in the station's oxygen and air tanks, venting the entire round's supply of oxygen into space.

An extremely fast method that involves a clever use of the waste system is the following:

1. Reconfigure the piping to connect the waste system directly into the pure pipes.
2. Find a place with a waste pipe next to a distro pipe, then configure them so that they can united later.
3. Open the valves for your deathgas mixture of choice, the waste piping should now begin to fill with your gases.
4. Set as many air alarms as you can to have every vent at Internal 0.
5. When ready, go back to your distro/waste pipe spot and unite them.
6. Listen to screams over the radio.

Other antagonistic things to do:

• You can hack an air alarm to use it as a non-Atmos Tech.
• You can C4 the digital valves to let you remove them and shut down AI control, or save a C4 and disable the cameras if you know there's no Cyborgs on the station.
• Using a gas filter turned on to pour large, ever increasing, amounts of gas onto a single connector port has no visible effects, but if you wrench a canister onto it then the canister will almost immediate fill up with the massive pressure buildup, letting you get super-high pressure plasma/CO2/etc canisters to hit area's with.