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.

When worked by a master, atmospherics grants powers many consider to be... Unnatural.

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 how Atmos works the way it does, making you ready for all kinds of situations.

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 lizard-people 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 when in a tank. 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. Can be mined from Lavaland with a bit of ingenuity, but generally will never need to be done unless using an extreme tritium synthesis setup.

N₂

Nitrogen. Not particularly more heat absorbent than any other gas. However, it cannot burn at all, which may slow down fires simply by taking up space. It can reduce the heat penalty on the SM, which will keep temperatures down.

Can be found in Atmospherics in green canisters. Can also be gasmined from lavaland.

Air

A 1:4 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.

Water Vapor

Pure H₂O. Keep away from the Clown - this slips people and even freezes tiles when released at low temperatures. Can be used as fusion fuel to make particularly exothermic reactions. Generated as a waste product when tritium combusts with oxygen. In fact so much of it is generated that it lowers the heat of the gas by a massive amount and drastically lowers the temperatures of active burn chambers by half, even more if permitted to accumulate. Also dissipates on its own when creating wet tiles.

The Janitor starts with a tank in his closet. Outside of atmospherics, it can be used to clean large areas very quickly.

CO₂

What the fuck is Carbon Dioxide!? It's an invisible, heavy gas. 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. Also used as fuel for fusion, with an absolute minimum of 250 moles, though you generally want more.

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. 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. Used as an anesthetic in the surgery room and as a "pacifier" in security for especially robust criminals.

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

Plasma

Toxins. One of the two flammable gases on the station, plasma is purple and highly toxic. Used primarily for fusion, an absolute minimum of 250 moles is required to start the process, though you generally want to use more.

Heating this in the presence of a large amount of oxygen will cause the formation of tritium, an even more flammable gas that burns hotter, brighter and far deadlier than plasma.

BZ

BZ gas is a potent hallucinogenic that also put slimes into stasis, degenerates changeling chemicals and suppresses their hivemind. As a side effect, affected people will take low brain damage, but breathing more than 1u of the gas long enough will cause brain death. An extremely insidious gas that is much harder to detect than N20 or Plasma, or at least until the hallucinations start.

BZ is formed when N2O and Plasma are combined at low pressures. The optimal pressure for this is 0.5 atmosphere, or about 50 kPa. Efficiency might be higher if you get it even lower somehow, though.

If mixed in a tank with oxygen, it can be used for internals, to encourage spiritual development. Breathing it also produces BZ Metabolites.

Tritium

Radioactive, flammable gas that is used in plenty of chemical reactions. Created by heating loadsa O2 with Plasma. Also, radiation collectors convert plasma into this. Tritium, though not naturally radioactive, releases radiation when it is burned. Might not want to put this into any engine unless you plan to set it on fire.

Tritium is created in fires that are highly oxygenated, or, in fires where oxygen takes up a vast majority of the gasses. For example, 97% oxygen and 3% plasma. Different ratios may be used, and sometimes different ratios will end up being better for the highest level of efficiency depending on space in the incinerator and temperature of the fire. Experiment! Important to remember is that tritium will likely be very hot, and if allowed to react with oxygen will burn up into water vapor. Keep this in mind when attempting to get sizable amounts of it.

Hyper-Noblium

Extremely inert, Hyper-Noblium stops other gases from reacting. (Specifically, it stops reactions when >5 moles). The rarest and most precious gas in the game and for good reason. Each mole synthesized contributes 1000 research points into the R&D servers, and synthesizing around 500 moles in a shift is usually enough to get all the researches.

Can be created when Nitrogen is combined with Tritium at extremely high temperatures. BZ works as a catalyst. 20:10 Nitrogen and Tritium respectively is consumed when one mole of Hyper-Noblium is condensed. Counter to the Nitrium reaction, BZ is not a requirement at all. But rather, it decreases how much the temperature / energy drops of your gas mix during the reaction. As such, BZ can often be entirely ignored. The minimum temperature for this reaction to occur is 5000000K, making fusion absolutely critical in its manufacturing process.

Anti-Noblium

The evil twin of Hyper-Noblium. Breathing it in will burn you from the inside out, even negating Hyper-Noblium's reaction and fire neutralizing properties in an explosive fashion. Expect anyone breathing this to die a very quick and painful death, especially Plasmamen.

Created by using the electrolyzer on Hyper-Noblium at a 1:1 conversion ratio, and as a minor result in the Nitrium Energy Ball reaction.

Nitrium

Nitrium is created by combining Nitrogen, Plasma and BZ with at least 50 mols of N₂O present as a catalyst. the ratio of gases is 5 parts Nitrogen, 2 parts Plasma, 2 parts BZ and 0.5 parts N20 which need to be heated to fusion temperatures for the gas to form. Nitrium can be used in internals mixed with oxygen for various effects.

An example of a mix for Nitrium would be 53% Nitrogen, 21% plasma, 21% BZ and 5% N₂O this is not the most efficient mix but it offers a good starting point and leaves little room for failure, don't forget to cool the gasses before adding them to the canister if you want to make a decent amount of Nitrium.

Pluoxium

A non-reactive Oxygen substitute that delivers eight times as much O2 to the bloodstream, with as little 3 kPa minimum pressure required for internals!

Formed by irradiating tiles with 2 part CO2 1 part O2 in the air. The Supermatter is often the greatest source of pluoxium, though it would require adding CO2 into the cooling loop. Depending on the efficiency of the setup, you can get between just enough pluoxium to fill an internals tank or so much that you consume all the CO2 within the station's atmospheric reserve tanks and export it via cargo for upwards of 500 thousand credits. Be careful when attempting the latter however, pumping the SM full of CO2 and O2 risks a tritium delamination which is nigh impossible to contain unless your setup is extremely robust.

Miasma

Miasma is created from rotting corpses, gibs, and other things. Miasma smells bad and can cause diseases to spontaneously appear. The higher concentration of miasma in the air, the higher level symptoms can appear. Can be converted back into oxygen by heating it to 373.15K. Also generates a small amount of research points when converted this way. Miasma production consumes oxygen and will not be produced from bodies in space or the oxygen level reaches a partial pressure of 18 kPa.

Dilithium

Dilithium is procured from lavaland crystals by miners, then stuffed into a blender and mixed with water. This way, each crystal generates about 200 moles of gas. It lowers the temperature threshold required for fusion asymptotically to 425K depending on the amount. This makes it completely impractical and useless, unless it's used with a very specific and complicated Supermatter Engine setup...

Freon

On temperature lower than 0°C (273.15 K) Freon will create an endothermic reaction with O₂, meaning it will absorb heat from the atmosphere, down to a minimum close to 50K. Adding Pluonium will catalyse the reaction so that it may begin at temperatures up to 310 kelvin, which is above room temperature. This reaction produces CO₂ and if the temperature is between 120-160K the reaction has a small chance to also produce solid sheets of hot ice .

Breathing freon causes burn damage.

Freon is made by combining a minimum of 40 moles Plasma, 20 moles CO2, and 20 moles BZ in a endothermic reaction at temperatures above 473.15 K. The consumption ratio for the reaction is 6 Plasma : 3 CO2 : 1 BZ. Higher heat improves the rate of reaction.

Hot Ice

Hot ice is a solid byproduct of the cooled Freon+O₂ reaction at 120-160K. Can be sold to cargo at a high price. It holds a great amount of power inside. Can be ground to produce 25 units of Hot Ice Slush.

If hit with a welder or burned the hot ice will melt, releasing the power stored inside. This releases large amounts of hot plasma into the air. (Moles of plasma released = 150 x number of sheets) and (Heat released = 20 x number of sheets + 300K).

Hydrogen

Hydrogen is a flammable gas which when ignited burns similarly to tritium. Hydrogen is made by electrolyzing Water Vapor with an electrolyzer machine. Hydrogen is solidified in a reaction with BZ as catalyst at high heat and pressure (over 1e4 for both) to produce metal hydrogen, which can be used to make armor, a fireaxe, and a Hardsuit. Metal Hydrogen can also be created within the Crystallizer.

Healium

Healium is a red gas which acts as a stronger sleeping agent than N₂0, while healing burns, bruises, suffocation, toxin and clone damage. When the user is unconscious and below 0C, it also restores blood and treats all wound types. It is created by exposing Freon to BZ in an exothermic reaction at temperatures between 25-300 Kelvin (keep it chill). Freon is consumed at around 11x the rate of BZ.

Pluonium

Pluonium is a highly reactive gas, but non-toxic when breathed. It is created in an endothermic reaction when Pluoxium is exposed to H₂ at temperatures between 5000-10000 K. Hydrogen is consumed at around 10x the rate of Pluoxium.

When between temperatures of 250-300k, Pluonium solidifies gaseous Plasma into bars

When between temperatures of 260-280k, Pluonium reacts with BZ to cause localized hallucinations in an exothermic reaction

When between temperatures of 150-340k, Pluonium reacts with tritium to produce H₂

Pluonium reacts with at least 150 moles of H2 to create more Pluonium in an exothermic reaction

Halon

Halon acts as a fire suppressant by removing oxygen in the air (while producing CO2) in an exothermic reaction if the air temperature is above 100 C or 373.15 K. The oxygen suppresion rate is 20 O2 : 1 Halon. It is created by combining BZ and Tritium in an endothermic reaction between 30-55 K. Tritium is consumed at around 16x the rate of BZ.

Zauker

Zauker is an incredibly deadly gas if inhaled. It is made by mixing Hyper-Noblium and Nitrium in an endothermic reaction at temperatures between 50000-75000 K. Nitrium is consumed at around 50x the rate of Hyper-Noblium. It is worthy to note that Hyper-Noblium stops reactions when it is present in quantities above 5 moles, prepare accordingly!

Zauker also decomposes exothermically into a 30/70 O2/N2 mix when exposed to Nitrogen.

Hexane

Hexane is a very dangerous gas that makes you hallucinate, gives you brain damage (33% chance to do 5 damage every time you breathe it in until you hit 150 damage), prevents you from using changeling chat, gives you a slow down and makes you immune to radiation.

Hexane is created in an endothermic reaction when BZ is exposed to Hydrogen at temperatures between 450-465k. Hydrogen is consumed at around 20x the rate of BZ.

The Atmos Devices

This will be a section detailing the overall function, and some specifics, of the various pipes, pumps, and other devices. Some details will be missed, but it will provide a basis. The first instance of a device running into a unique mechanic will be explained in further length.

Digital Valve

A valve that opens when clicked, and connects the two pipenets it separates when doing so. A pipenet is any collection of normal pipes connected together, including some sub types. Counter to pumps, it experiences no delay in its gas transfer. It essentially acts as a pipe, which, as all pipes, transfers gas instantly to all connected pipes. Has 200L of volume on one side, and 200L on the other end. This can be operated by both carbon mobs such as humans, excluding xenomorphs, and silicons.

Pressure Valve

An activatable valve that lets gas pass through if the pressure on the input side is higher than the set pressure. Good for situations where you need to keep pressure under a certain level.

Manual Valve

Acts identically to a Digital Valve, however, the manual valve does not allow silicons to operate it. Good for when you do not want the AI interfering with atmos.

Pressure Pump

An oddball case. Like all pumps, it separates connected pipenets if there is nothing else connecting them. Has a maximum pressure of 4500 kPa. All pumps work by pumping the contents within them to the other side, which is 200L on one side, and 200L on the other. Any pump can not pump gas that is not actually in it, which means that very large connected pipenets will have lower pump speeds. Pressure pumps work by gradually building up to its set pressure per tick. Because of this, pressure pumps slow down when approaching their target pressure, and will not quite match their pressure after a very long time, but will get very close.

Volume Pump

The volume pump is similar to the pressure pump, but operates differently. It has a pressure limit of 9000 kPa. However, this limit only kicks in when the output pipenet is currently over 9000 kPa. The pump will work if the output pipenet is below 9000 kPa, even if the resulting pressure of this action would be way higher than 9000 kPa. Counter to the pressure pump, this pump works on a L/s basis. This has a 2x200L volume as well, so you pick how much of the volume in the pump is actually pumped to the other side by changing the number. Because its max speed is 200 L/s, it will always outpace and outpressure the pressure pump. Can be overclocked using a multitool, which will cause its pressure limit to be dependent on the input pipenet, which will tend to make the maximum output pressure higher. However, this will cause 10% of gas running through it to spill.

Passive Gate

These are a combination of pumps and valves. They work up to their set pressure, with a maximum of 4500 kPa. These can never do more than equalise the two connected pipenets, just as valves do. However, they only work one way, rather than mixing the gas between the two pipenets perfectly as valves do. Very rarely used as the pressure valve tends to fill most of its use cases, but can be used in situations where one needs pressure control for a pipenet that needs to remain between two values, the upper bound being the set pressure and the lower bound being the output pipenet pressure, such as a BZ reactor.

Temperature Gate

A gate that only lets gas through when they are on one side of the set temperature threshold (either greater, or lower). The mode can be changed by using a multitool on the device. Excellent for precise thermal regulation and failsafes for the SM engine.

Unary Vent

The vent will pump gas into the room it is in, depending on the air alarm settings of the room. The air alarm has two settings to worry about, External, or Internal. External works by making the vent pump gas from its connected pipenet into the room until the room, or more accurately, the tile, matches the pressure that is set. The max pressure you can configure for External is 5066 kPa, and it slows down when approaching the set limit, as pressure pumps do. Internal works by pumping gas into the room from the pipenet until the pressure set matches the pressure in the connected pipenet. Examples: a vent set to External 200 will pump gas into the room until it is 200 kPa. A vent set to Internal 300 will pump gas into the room until the connected pipenet's pressure is 300 kPa, regardless of room pressure. As such, Internal 0 will always pump at full strength. This same effect can be achieved by turning off both External and Internal. The vent has a maximum speed it can pump at, even when extremely pressurised.

Passive Vent

An unpowered vent that equalizes the internal and external gases, think of it as a simple open-ended pipe into the atmosphere. It is not interactable and cannot be closed. It too, is not restricted by pressure as with the other vents, opening possibilities for interesting shenanigans.

Injector

The injector is similar to the vent in that it pumps gas onto the tile it is on. However, it is not controlled by an air alarm, but rather works by hand. It is also in L/s units again, similarly to the volume pump. Also similarly to the volume pump, it is the faster one when compared to its pressure based cousin, the vent. It does not have a maximum pressure change per second, as vents do, and will always outpace them. This comes at the cost of the control that vents give you.

Scrubber

The gas sucking cousin of the vent, which sucks gas into the connected pipenet. Scrubbers are operated using the connected air alarm. They only suck in gas that is on their tile, unless you set their range to Expanded, in which case it'll suck in a 3x3. Setting them to Siphon will make them suck in every gas. If the scrubber is not on siphon, you can select specific gases for it to suck into its pipenet. Maximum pressure they can reach in the internal pipenet is 5066kpa before they stop scrubbing/siphoning, very important for SM engines!

Heat Exchanger

Place two of these next to each other, facing each other, and they will equalize the temperature of the gases inside them. The heat exchanger is not part of the heat exchange pipes system and therefore does not bleed heat into its turf.

Filter

The filter is the first device that connects 3 pipenets. It can be set to a single gas, and it will dump this gas to the side it is pointing in. All gas that is not selected will continue straight forward, as the arrow is pointing in a single line. When set to Nothing, it will allow all gas through the straight path. The filter works in L/s, and as such does not experience pressure related slowdowns, however, it has a pressure maximum of 4500 kPa. When EITHER OUTPUT SIDE is 4500 kPa or above, the filter will not function, not allowing any gas to pas. That is, both in a straight line and on its offshoot, the pressure must be less than 4500 kPa.

Mixer

The mixer also requires 3 connections to function, as the filter does. The mixer will mix the two incoming gases using the ratio the user inputs, starts off at 50/50. Node 1 is the input in a straight line with the ouput, Node 2 is the offshoot compared to the output. Both inputs need to have gas in them to function unless a side with gas in it is set to 100%, in which case it will function and purely let that side through. Is pressure based, with the associated properties. Also has a pressure maximum of 4500 kPa. The mixing is influenced by temperature following the ideal gas law. When one of the input sides is hotter compared to the other input, it will let less of this side's gas through, mol-wise. This will give you scuffed ratios if you do not equalise temperatures, if you need the precision, make sure they're equal.

Heat Exchange pipes

Functions like regular pipe, however, this will attempt to equalise the temperature between the pipenet and the space it is in. This is based on heat capacity, which can be found on this page. Higher heat capacity means a gas will soak in more energy, which means it is better at cooling when cold, and better at heating when hot. These pipes commonly see use in Supermatter setups, to cool down the coolant by using these pipes in space. However, they can also be used to heat up places, of course. Has a 10K efficiency loss. Space is 2.7K, but heat exchange pipes will only cool the gas in them to be about 12.7K.

Heat Exchange Junction

These are used to transfer from normal pipes to heat exchange pipes. These need to be between a pipe, or pump, etc. and heat exchange pipes for gas to actually be transferred between the two different kinds of pipe. While this pipe looks partially like a heat exchange pipe, it does not equalise temperature in the way that heat exchanging pipes do. It only looks like it does, so these can be safely connected to any pipe in a normal room without risk.

Layer Manifold

Connects the 5 different layers of pipenets. For most stations, the red scrubber network will be on layer 2 while the blue air supply pipes will be on layer 4. Default layer is 3. Pipes on different layers do not interact with one another.

Physical Characteristics of Gases

TL;DR Gas flows from high pressure areas, to low pressure areas. Gas uses up more room when hot, less room when cold.

Ideal gas law: PV = nRT

Where R (ideal, or universal, gas constant) = 8.31, the following are linked by this equation.

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.

Item	Volume
Emergency Oxygen Tank	3
Extended Emergency Oxygen Tank	6
Double Emergency Oxygen Tank	10
Oxygen Tank (blue/red)	70
Plasma Tank	70
All pipes	70
Pipe manifold	105
Locker	200
Coffin	200
Gas Pump (each side)	200
Volumpe Pump (each side)	200
Passive Gate (each side)	200
Heat Exchanger	200
Gas Filter	200
Vent	200
Scrubber	200
Portable Scrubber	750
Gas Canister	1 000
Tile / turf (any area)	2 500
Portable Pump	1 000
Unmovable pressure tank	10 000
Huge scrubber	50 000

Moles (n): 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. Moles can be calculated by a form of the ideal gas law. n=(P*V)/(R*T)

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. Heat capacity defines how much energy it takes to raise the temperature of a gas. The normal air mix (%30 O2, %70 N2) has a specific heat capacity of about 20 which doesn't impede heat transfer very much. Fires spreads quicker in gases with low heat capacity, and slower in gases with high heat capacity.

Gas	Heat capacity
O2	20
N2	20
CO2	30
N2O	40
Plasma	200
Water Vapor	40
Hypernoblium	2000
Antinoblium	1
Nitrium	10
Tritium	10
BZ	20
Pluoxium	80
Miasma	20
Dilithium	55
Freon	600
Hydrogen	15
Healium	10
Pluonium	30
Halon	175
Zauker	350
Hexane	5

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: 10x more O2 than plasma, and with as high a temperature as can achieve.

In short the colder the gas and the higher the container volume, the more moles you can fit inside. This is why hot gases clog the red waste pipes - they expand, allowing fewer moles to be transported.

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 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:

The gasses are pumped through the cyan tubes from their respective tanks (N2, O2).
They are mixed in the air tank (Air) to a 1/5 mix of O2 and N2.
The breathable gas is then pumped through the cyan loop to the north of Atmospherics.
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:

Scientist Bill messes up and fills the Toxins Lab with plasma but fortunately manages to evacuate the room safely.
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.
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.
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.
The plasma finally reaches the Plasma Filter.
Here the plasma gets extracted from the waste gas and pushed into the big plasma tank-room outside the windows.
The plasma stays in the room until someone decides to pump it out.
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 throw it out the window~~ and get down to business. The two machines at the top can dispense infinite pipes, and your wrench can disconnect and connect pipes to each other. Remember, you cannot disconnect pumps if they have too much pressure in them.

The dumbass-version of the Atmospheric 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!

For the love of Nanotrasen, at least do this:

Get a Volume Pump from the Pipe Dispenser at the north side of Atmos and replace the green circled normal pump with a volume pump, making the waste gas -system >100x more efficient. We want the waste gas sucked from the station into the waste system as soon as possible!

This is good as well:

Go through the N2 and O2 (besides southern wall) and set their output to 4500 kPa.
Set the pumps next to the computers at 4500 kPa also, so the gases being pushed out of the gas-room get moved fast too.
Set the Air-computer's output to maximum (5066.25 kPa).
Replace the blue circled normal pump with a Volume Pump as well, but notice; there are risks involved and all of them are covered at the pros and cons -section below.

Pros and cons of this whole 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.

+ Reduced pipe sabotaging: With this setup, its harder for the grifflords to 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 fling the unwrencher in a random direction.

- 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 pipe manipulating: If you suddenly have to modify any of the distribution pipes around the station, you need to lower the pressure to under 303.9 kPa if you don't want to be flung around like a leaf in the space wind, which can 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 siphon 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 the operating mode to contaminated, 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 extremely extended oxygen tanks for internals use (instructions below).

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.
Go grab the Fire Axe from the wall mount and hide it somewhere so 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 are 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.
An emergency oxygen tank with normal settings lasts for about 12 minutes. Same tank, but with optimized gas temperature and output settings reduced, lasts about 50 minutes. If you don't have resources to get cooled O2 right now, set your output pressure to 16 kPa, it will give you 31 % more time to breathe.

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 station's distribution loop, maybe other places can be set up like this as well?

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 an 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.
Pressures 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 defense.

ATMOS Resin

The Backpack Firefighter Tank can switch modes to launch transparent ATMOS resin instead of extinguisher. This resin has the following effects:

Repairs hull breaches similarly to Metal Foam.
Cleans the air from toxins.
Normalises air temperature to room temperature (20°C or 293.15K).
Removes slipperiness from floors (from water etc).
The foam itself is not slippery.

To use the Backpack Firefighter Tank, equip it on your backpack slot and click the new hud icon to take out the nozzle . You can then cycle modes between extinguisher, resin launcher and single tile resin launcher (foamer) by activating the nozzle in your hand. It spends water when used. Examine the nozzle to see water remaining. This anti-breach and firefighting tool can be ordered from cargo or found in atmospheric lockers.

Useful Atmos Trivia

Your holobarriers let people walk through, yet block gases. Very useful for cleaning up Plasma spills, fixing hull breaches and keeping fires in check.
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 an O2 tank placed in the canister, and then open the valve between them. You will also need to run very, very fast.
Gas pumps are for precise pressure control, volumetric pumps are for really fast pumping, and passive gates are for having 'one way' manual valves.
Straight piping is faster than any volume pump or gas pump, regardless of the amount. You only want a volume pump if you have a good reason for separating two pipenets from each other. For that reason, many of the pumps in the SM and even in atmospherics is useless.
If about to unwrench a pipe known to contain deadly gas, use a holobarrier on the tile first, then unwrench, this will keep the gases isolated to that specific turf. You can then bring your portable gas scrubber to the holobarrier'd tile and clean it up much, much faster and much safer than if you had unwrenched it without a holobarrier in the first place.
BZ deals damage based on the pressure, not percentage of the air that is being breathed in. This means that hot BZ is more effective than regular air-temperature BZ. This just might give you a bit of an edge when plasmaflooding, or if you want to use an invisible deathgas flamethrower.
A flamethrower containing extremely chilled gas such as n20 can flood a room very, very quickly. This is useful as an antagonist, but also for cooling down the SM if all your cooling breaks down for some reason.
A scrubber connected to a very large spaceloop is much more effective than a scrubber connected to a freezer. This is because of the added volume allowing the scubber to dump more moles of gas into the connected pipenet.
Using a pump of any kind after a scrubber is highly redundant and drastically lowers the effectiveness of the scrubber as it separates the pipenets and cuts off volume. The SM and the incinerator's scrubbers can be massively improved by simply replacing the pump with a straight pipe.

Crystallizer

The Crystallizer is a machine that allows gases to be solidified and made into various materials.

The working principle and gaseous requirements behind the crystallizer is rather simple and explained in the machine itself. You select a recipe, pump gases in using the input (green) port, meet the temperature requirements, and wait for the material to finish crafting. The red port is used for heat control, as it will conduct with the internal mix and influence the temperature. You have a 10% wiggle room for the temperature requirements, but straying too far from the optimal temperature will influence the final quality of the item produced. Quality affects the amount of gas consumed for each product produced, with higher qualities consuming less gas. The optimal temperature for any given recipe is the median between the lower and upper temperature bound. Stay as close as you can to the median value, and you'll be able to save up to 85% of the required gas if you manage to make the highest quality!

It currently supports the production of:

Item	Properties
Metallic Hydrogen	A crafting material used for golems, axes, or the Elder Atmosian armor set.
Hyper-Noblium Crystal	A two use potion that can be used to pressure-proof two clothing items, turning them an icy blue color.
Healium Crystal	A grenade that can fix a large are of air to more reasonable temperatures. Good for firefighting and freezing temperatures.
Proto-Nitrate Crystal	A grenade that can refill a room with nitrogen and oxygen with a 8:3 split respectively.
Nitrous Oxide Crystal	A grenade that will release Nitrous Oxide (Laughing Gas).
Hot Ice	A material normally prodouced by freon combustion, also craftable with the Crystallizer. When weldered or burnt, it rapidly releases a very hot and dense cloud of plasma gas.
Ammonia Crystal	A material with not much use except for exporting. Makes 2 every time it's completed.
Supermatter Shard	A smaller version of the extremely dangerous Supermatter Crystal used for power generation.
Diamond	A sheet of diamond. Many crafting and manufacturing applications. Used thorough the station.
Plasma Sheet	A sheet of plasma. Many crafting, manufacturing, and biological applications. Used thorough the station.
Crystal Cell	A non rechargeable cell with a huge power capacity. Rated at 50 MJ.
Zaukerite	A material without much use except for bragging rights. Makes 2 every time it's completed.
Crystal Foam Grenade	A grenade that functions exactly like the standard Smart Metal Foam grenades that can be found roundstart. Extremely simple to make compared to most other recipes.
Nitrium Crystal	A grenade that on detonation releases a chemical smoke cloud containing chemical Nitrium and Nitrosyl Plasmide.

Fusion

NOTE: The following guide covers the bare essentials of fusionv6 and should be enough for you to get started with your first few fusion canisters. The more complex bits regarding the kicked rotor, open-tile fusion and SM utilization will be provided at a later date, the essentials are being rushed out so that there's at least something there to work with.

The fluff

Plasmic fusion is distinctly different from stellar nucleosynthesis in real life. While standard fusion consists of a one-way transformation of light elements into heavier elements with leftover energies being released as light and heat, Plasmic fusion uses a completely different method of converting plasma into CO2 and vice versa while consuming tritium. This process is poorly understood and subject to heavy internal debate by leading Nanotresen scientists and atmospheric technicians, as such what can be currently provided is subject to corrections once the mechanism is understood.

There are 4 requirements to plasmic fusion: Lots of plasma, lots of CO2, lots of tritium and lots of heat - the result is a LOT more heat (by several orders of magnitude), a lot less of your starting gases and enough rads to make the SM feel thoroughly inadequate. The radiation itself, while deadly enough to kill when a subject experiences 30 seconds of exposure, or is hit by even a single cluster of hyperenergetic decay particles, is a tiny threat compared to the ravaging heat of a newborn star shackled by the confines of your canister, begging to be set free and set the station ablaze. A containment failure of a fusion canister will result in severe consequences and definitely something the gods will notice, so be careful when attempting it. Also, atmos techs are a very closely-knit community and most techs who learned fusion were taught or in some way assisted by a tech who knew it beforehand, if you find a willing tech, ask him to teach you as this is an extremely dangerous and autistic activity.

The magic ratio

Disclaimers and safety pronouncements, aside, let's get to what you actually need when doing fusion. There are different recipes for achieving fusion, but the most well-tested, consistent and widely used recipe is the 6 plasma : 2 CO2: 1 Tritium recipe popularized by the first atmosians who birthed stars. One such canister should have 6000 moles of plasma, 2000 moles of CO2 and 1000 moles of tritium - the amount does not need to be exact and can vary by as much as 10% in ratio, as long as the 3:1 ratio between plasma and CO2 is preserved. Technically, a canister can fuse as long as it has a minimum of 250 moles of plasma, 250 moles of CO2 and 1 mole of trit, but the results are not particularly useful or exciting. Any amount of plasma and CO2 are okay, provided that they follow the ratio, and the fusion reaction will continue until it has less than 250 moles of CO2 or plasma, or it runs out of tritium. Once your canister is nicely made, heat it up to 10.000°K via heat pipe exposure over an actively burning tritium chamber (the incinerator has all the necessary equipment, and is probably where you made your tritium to begin with), then please unwrench it when it hits the 10.000°K mark.

Update: The 6:2:1 ratio is still generally very successful and widely used, but a more precise method of creating mixes that work has determined that not all 6:2:1 ratios are optimal. See the section on the mathematical background for more information. If starting out, stick to 6:2:1 until you're confident enough to experiment a bit more.

When it works

You'll know you're successful when bright shiny multicolored particles start flying out of the canister. Please note that these shiny particles are extremely radioactive and just one of them hitting you is guaranteed fucking death if you aren't in a radsuit or aren't a radiation immune species such as plasmaman or preternis.

Once your canister is nice, hot, finished and ready; and you aren't a dying radioactive meatbag clinging desperately to his last vestiges of life, you may proceed to use the fusion canister for generating hypernoblium, or maybe nitrium, in large batches, for personal consumption or shipping to cargo. A good canister of hypernoblium is easily worth half a million cargo credits, skilled atmos techs consistently make ones worth upwards of several million credits. Alternatively, you can use the fusion canister as a traitor and unleash your newborn star onto the station, killing anything and everything inside as it is engulfed in an expanding cloud of gas hotter than the heart of many suns.

Help, I am glowing and my skin is made out of acid

If you are exposed to radiation without the appropriate insulation or hit by a particle, do not panic, take your charcoal/antitox/anti-rad pills and you should be able to tank the toxin damage from the rads and keep some mutadone with you if you mutate (you will). If not in a rad suit, do not immediately run to medical because you will contaminate it and get a lot of people killed. Instead, scream over radio that you need radiation treatment in the form of more anti-tox or charcoal dropped off in maintenance for you to grab and use. Do not let doctors or paramedics get near you, you'll only get them killed unless they're rad immune already. If hit by three of these, hope that you have enough medicine to keep you alive, as the next 10 to 20 minutes will be hell for you as your radiation damage accumulates and you mutate into a filthy subhuman. If hit by 5 or more of these, even if in a radsuit, isolate yourself and suffer a colorful death.

I would like to understand the mathematical background of fusion dynamics and/or have severe autism

The deeper mathematical background of kicked rotors is not a place you generally want to go unless you're doing some extremely specific shenanigans, or want to add to the code. It has taken me a year of experimentation (sporadic, granted) and testing to understand its full nuances and explaining it in text is not something I can do well enough to teach you. Hell, it took impending retirement to get me to finish writing it down. You will need to do a significant amount of in-game testing and some research on the more mathematical parts of the internet to understand it truly, but hopefully this lecture will help you piece it together much faster than it took me to.

Tips for working with fusion:

at the highest efficiency roughly 30% of the gas you use will be lost to the pump to the canister and to the heat exchanger to the can so prepare accordingly.
Work with friends. It has high setup and maintenance requirements, and your fellow atmos techs, engineers and toxins scientists are all valuable resources in your pursuit of very hot things.
It is intended to preform fusion in a canister but doing it in a pipe net or incinerator is possible.
Heat exchangers are your friend for starting your reaction. Connect it to tritium burn chamber or canister to get the heat needed to start it.
Should you want to release a canister that you used for fusion in a room full of people, consider shooting it to break it open so you aren't right next to it.

Beyond the basics:

You can harness the radiation produced from fusion to produce power using rad collectors. Earn your keep as a member of engineering. Or just use it for pluoxium production.
The higher the temperature, the prettier the fire. See if you can get the prettiest color fire.
Traitors can harness fusion reactions to devastating results if done correctly.

Being a Traitorous Scum

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

Open valves connected to harmful gas you want to add to the station.
Set pumps to the distribution loop to maximum pressure output (4500 kPa).
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).
Open valve from custom mix chamber.
Turn on pump leading to distribution loop.
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).
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:

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.
Open the valves for your deathgas mixture of choice.
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:

Reconfigure the piping to connect the waste system directly into the pure pipes.
Find a place with a waste pipe next to a distro pipe, then configure them so that they can be united later.
Open the valves for your deathgas mixture of choice, the waste piping should now begin to fill with your gases.
Set as many air alarms as you can to have every vent at Internal 0.
When ready, go back to your distro/waste pipe spot and unite them.
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.
Make flamethrowers, complex mixes involving multiple gas types are the best ones, and they only need one puff to render a room uninhabitable
Manufacture bombs like in toxins, except without needing to use a tank transfer valve.