Gas Management Guide: Mechanics & Setups

Gases are the game’s atmospheric phase: they move, stratify by density, carry heat and germs, condense/evaporate into liquids, and power or break buildings. Controlling gas composition, pressure, temperature and flow is central to life support, power, cooling and many late-game systems.

Gas basics

• Gases occupy tiles and will always expand into adjacent vacuum tiles (unless mass is vanishingly tiny). They do not “pile” like liquids; they diffuse, convect, and stratify.
• Stratification: lighter gases rise above heavier gases. Use density differences to passively separate or trap gases (e.g., Hydrogen will float above Oxygen/CO2; CO2 will pool at the bottom).
• Condensation / vaporization: a gas condenses into its liquid form when cooled to 3 °C below its condensation point; a liquid evaporates when heated to 3 °C above that point. Managing phase change matters for gas coolants and for avoiding pipe damage.
• Gases and germs: gas tiles carry germs and exchange germs with other gas tiles. Polluted sources (Slime, Polluted Dirt, Polluted Water) emit Polluted Oxygen and spread germs into the atmosphere until local pressure caps their emission.
• Destruction in space: gases exposed to open space are destroyed unless protected by Drywall or some enclosure.

Pressure and overpressure

• Many buildings and critters have pressure operating ranges. Overpressurizing a room can stop oxygen-producing buildings or cause stress effects (e.g., “Popped Eardrums” when gas pressure > 4 kg/tile without a suit).
• Some plants/critters require a minimum pressure to grow (many plants need ≥ 150 g/tile).
• Gas Reservoirs: store gas but release contents on catastrophic damage — avoid exposing reservoirs to extreme environments. A reservoir only exchanges heat with the tile containing its output port and the tile directly below that; the reservoir body itself exchanges heat with its 15 tiles but not directly with its stored gas.

Heat and gases

• Gases transfer heat via convection (hot gas rises) and by conduction with adjacent tiles and objects; specific heat capacities and thermal conductivities differ across gases.
• Some gases are excellent for thermal roles:
  • Hydrogen: high specific heat and thermal conductivity among gases — best low-temperature coolant and radiative gas in some heat-exchange setups. It has an extremely low condensation point.
  • Natural Gas and other light, high-SHC gases can act as decent insulators / heat sinks in specific setups.
  • Chlorine has low SHC and low thermal conductivity, useful where minimal heat exchange is desired.
• Buildings and gas circuits:
  • Radiant Gas Pipes conduct heat using the average thermal conductivity of pipe material and the gas within. Gas pipes have lower throughput (1 kg/s) than liquid pipes (10 kg/s), making them less effective for heat transfer in most cases.
  • Because gas throughput is small and many gases have low TC/SHC, Radiant Liquid Pipes are generally superior for active heat exchangers; gas circuits are mainly used for extreme-temperature situations (gases don’t boil) or when using Hydrogen for low-temperature deletion.
• Temperature limits and floating-point thresholds: some insulated tiles and tiles with large thermal mass require significant ΔT before heat exchange occurs because of internal floating-point and exchange thresholds. Very small temperature differences may result in no heat exchange.

Common gases and roles

• Oxygen / Polluted Oxygen
  • Breathable for Duplicants. Oxygen is lighter than CO2 so it rises above it.
  • Produced by Electrolyzer (1 kg/s water → ~888 g/s O2 + 112 g/s H2) and by algae-based equipment (Algae Terrarium, Oxygen Diffuser) and Oxyferns (convert CO2 → O2).
  • Oxygen Diffuser: uses algae, outputs Oxygen at around 30 °C (or hotter if inputs are hotter). It stops operating if the tile it sits on exceeds 1800 g of gas (overpressure).
  • Oxyferns: domesticated convert CO2→O2 efficiently and multiply input gas mass by 50 (50 g O2 per 1 g CO2 consumed). They have a very high upper pressure limit and can create runaway oxygen if sealed incorrectly.
• Carbon Dioxide (CO2)
  • Heavy gas that pools at low points; sterile in high concentrations (useful for frozen food storage).
  • Produced by duplicant respiration (2 g/s), many generators and industrial buildings, geysers, and critters (Slicksters).
  • CO2 can be captured into Polluted Water via Algae Terrariums or Carbon Skimmers.
• Hydrogen
  • Very light, low-condensation gas. Valuable as fuel (Hydrogen Generators) and as an excellent gas coolant.
  • Geysers and electrolyzers are primary sources. Hydrogen pooling and storage require care (it rises and will seek high points).
• Natural Gas, Sour Gas, Methane
  • Natural Gas is a usable fuel (Natural Gas Generator) and can serve as a thermal medium in some designs.
  • Produced by Natural Gas Geysers, Oil Refineries, Oil Wells.
• Chlorine
  • Produced by Chlorine Geysers and some chemical processes. High condensation point compared to many gases — can be found liquid in very cold biomes.
  • Useful for disinfecting and as an atmosphere for certain plants.
• Polluted Oxygen
  • Breathable gas that carries germs; produced by Polluted sources and by some vents.
  • Deodorizers convert Polluted Oxygen → Oxygen using sand/regolith (with material costs).

Gas transport and piping

• Gas Pipes move packets at 1 kg/s through the network. Mixing different gases in the same pipe reduces throughput efficiency; avoid excessive merges/splits or filter gases early.
• Gas Pumps pull from a tile and push into pipes; Gas Vents output gas from pipes into tiles. Both respect pressure limits of connected cells (overpressure stops output).
• Gas Reservoirs hold up to 1000 kg (different from liquids) across 15 tiles and have specific heat-exchange behavior; compare with Liquid Reservoirs (5000 kg) when deciding what to store.
• Mechanical filtering and automation:
  • Gas Element Sensors and automated valves can build passive mechanical filters and atmospheric separators using density differences and controlled openings.
  • Electronic Gas Filters (Gas Filter) reliably separate pipe contents but require power and can fail if pipes back up; mechanical sensor-based designs can be cheaper but have caveats (power loss behavior, detection order).

Special mechanics and tricks

• Convection and buoyancy: use vertical shafts and layering to separate gases without piping; small holes at the right height can act as passive gas separators.
• Liquid airlocks and liquid stacking: by using unmixed liquid layers and the fact that gas cannot displace liquids, you can create airtight passages for duplicants while preventing gas exchange.
• Flaking / phase manipulation: extreme adjacent-temperature differences can cause liquids to flake into other materials (useful for converting crude oil → petroleum via heat).
• Wheezewort and other biological cooling:
  • Wheezeworts cool by absorbing up to 1000 g/s (domesticated) and releasing gas 5 °C colder. They work best on dense, high-SHC gases (Hydrogen gives the largest DTU/s effect). They never cool below 5 °C above the gas’s condensation point.
• Heat deletion with fuel-burning devices:
  • Hydrogen Generators, Thermo-Nullifiers, and other fuel devices affect base heat not only by released heat but also by deleting the thermal mass of their fuel. Preheating fuel can make some generators heat-negative at certain thresholds.

Safety and stress interactions

• Hot gases (steam, geyser outputs) can scald duplicants; Atmo Suits protect against scalding.
• High gas pressures cause stress (Popped Eardrums), low oxygen pressures cause Low Oxygen stress. Build appropriate suit docks, vents and sensors to manage atmosphere in work areas.
• Polluted gases and slimelung sources spread germs through the air — using deodorizers, chlorine atmospheres, or isolating polluted water/slime prevents airborne infections.

Designing reliable gas systems — practical tips

• Separate life support and industrial atmospheres: keep oxygen production and CO2 sinks positioned and ventilated to avoid overpressure and to prevent oxygen from stalling electrolyzers or hydrogen production.
• Use reservoirs and buffers: store intermittent geyser output (Hydrogen, Natural Gas) in reservoirs and automate pumps with Atmo Sensors to smooth supply gaps.
• Prefer Liquid circuits for high-throughput heat transfer; use gas circuits (Hydrogen) only when liquid coolants would boil or when you need extremely low-temperature performance.
• Filter early: remove unwanted gas contaminants near their source with filters or mechanical traps before they mix into main distribution loops.
• Mind condensation points: avoid cooling a gas below its condensation point within pipes or you'll form liquids that can damage or clog pipes and pumps.
• Use building placement to advantage: vents, pumps and diffusers interact with the tile they occupy — overpressure on that tile will stall the building. Leave vents open to lower-pressure tiles or use ventilation cavities to ensure effective exchange.

This covers the gameplay fundamentals and practical uses of gases: atmosphere composition, pressure, temperature effects, transport, and common gas-specific roles. Mastering gas behavior — stratification, heat exchange, pressure limits and phase changes — unlocks efficient life support, power generation and advanced thermal designs.