Vacuum

Vacuum is an environmental factor unique to locations in orbit, and represents the amount of breathable air within a room. Vacuum management is a vital consideration during trips into orbit and especially for spacebound colonies; plants will die if even briefly exposed to vacuum, and most living pawns will be severely endangered if caught in airless environments without sufficient protection.

Vacuum is never a consideration on planet-bound maps. In such locations, all tiles are always considered to be fully pressurized.

Summary

Measurement

Vacuum is measured as a percentage per cell. A cell with 100% vacuum is considered to be completely depressurized, while a cell with 0% vacuum is considered to be fully pressurized. All tiles within a room share the same vacuum level.

The vacuum level of a tile is listed in the tile's information area located above the Architect menu, just above its light level. A vacuum overlay can also be toggled on and off from the bottom right corner of the screen, and will visualize the vacuum level from red (100%) to green (0%).

Airtight rooms with at least 50% vacuum will have a visible overlay resembling gray clouds and white motes of dust, with its visibility inversely scaling with vacuum level; at 50% vacuum, the overlay will be nearly transparent, while at 100% vacuum it will be totally visible.

An airtight room with 100% vacuum.

Pressurization

In orbit, all outdoors areas are always considered to be a complete vacuum, no matter what.

Each building is designated as airtight or not airtight, visible in its information window. Pressurizable areas can be created by constructing spaces that are completely enclosed by airtight constructions. Whether or not walls and doors are airtight is determined by the stuff used to create them; metallic stuff types (other than obsidian) and bioferrite will create airtight walls, while all other stuff types will not.

Enclosed areas must be completely roofed to remain airtight. Even one missing roof tile will cause a space to instantly become a total vacuum, as will the removal of any building that is keeping the room airtight.

Open vents and doors will exchange vacuum across both sides of one another.^{[What rate?]} For practical purposes, this means that a single door leading to a depressurized area will cause the entire room to quickly vent whenever it is opened. To avoid unwanted depressurization, powered vac barriers can be utilized; otherwise, creating a manual airlock by using multiple doors in sequence will suffice as an unpowered solution at the cost of leaking a small amount of air whenever they are used.

Airtight spaces can be artificially pressurized with oxygen to gradually reduce their vacuum percentage, making them safe for living creatures to inhabit without protection. Oxygen pumps are the most accessible method for this, although archean trees can also be used on asteroids. Life support units can be found in some naturally-generating locations and faction bases that pressurize the room they are in at no cost, but they cannot be moved or deconstructed.

Danger

Vacuum is very dangerous to unprotected creatures. Humans and animals will take vacuum burns to uncovered body parts while caught without protection in vacuum, and will suffer from vacuum exposure that causes rapid loss of Consciousness and a quick death.

Roughly every hour, any and all types of plant except archean trees will instantly die if they are exposed to at least 50% vacuum.^{[Checks on long ticks -- describe more accurately?]}

Vacuum exposure

Main article: Vacuum exposure

Without complete vacuum resistance, a pawn that enters a tile with at least 50% vacuum will immediately begin suffering from vacuum exposure, which becomes more severe until they return to a pressurized areas.

Vacuum burns

Pawns in vacuum will suffer periodic vacuum burn injuries to random external body parts that are not covered by vacuum-resistant gear. This happens at an interval scaling linearly from one burn every 1,200 ticks (20 secs) at 50% vacuum to one burn every 300 ticks (5 secs) at 100% vacuum. Vacuum burns deal a flat 1-2 damage each - regardless of multipliers to incoming damage such as the Tough trait - and will combine together when inflicted to the same body part.

Vacuum burns never scar, and cannot become infected. This makes them mostly a tertiary danger compared to vacuum exposure, but the penalties caused by compounding burns can still add up to become a significant danger.

Pawns with the vacuum resistant or breathless genes will never suffer vacuum burns.

Gallery

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  A practical example of a simple unpowered airlock. Note the doors constructed in sequence.