Atmos

Active Vent

Updated 3/8/2026

Kit (Active Vent)

Active Vent

Deconstruction Steps

StepToolRecovered Item
1Hand DrillKit (Active Vent)

Description

The Active Vent moves gas between the connected Pipe Network and the atmosphere surrounding the active vent. It requires electric power to work (100 Watts).

The "PressureExternal" value limits the pressure of the atmosphere surrounding the active vent, preventing operation if reached. The "PressureInternal" value limits the pressure inside the active vent pipe network, preventing operation if reached.

Contrary to popular belief, both values are enforced, so the Active Vent comes with the functionality of a Pressure Regulator and simultaneously also Back Pressure Regulator. Note that setting these value and changing the Mode afterwards is ill-advised: Changing the Mode always resets both values to their defaults (1 atm/0 Pa for pumping into the room, 0 Pa/500 atm for pumping into the pipe), so they must be set (if at all) after setting the Mode.

  • In "Outward mode" (switch is blue), the Active Vent increases the external pressure by moving gas from the pipe network to the surrounding atmosphere, up to "PressureExternal", but never allowing the pipe's pressure to drop below "PressureInternal".
  • In "Inward mode" (switch is red), the Active Vent decreases the external pressure by moving gas from the surrounding atmosphere to the pipe network, down to "PressureExternal", never exceeding the pipe pressure set in "PressureInternal".

Note: Use this to remember visually what Color means which Mode when looking at the Active Vent:

  • Blue == Blow Note: Use this to remember which "Mode" logic type value is related to inward or outward:
  • Mode 0 == outward == 0utward
  • Mode 1 == inward == 1nward

The "PressureExternal" value is set to 100 kPa when the Circuitboard (Airlock Control) is used in a Console. This is the reason why the airlock is unable to pressurize when the atmosphere surrounding the active vent is unable to reach 100 kPa within the airlock.

The "PressureExternal" values can also be inconvenient on worlds like Venus whose atmosphere is well above 101kPa. Manually-operated airlocks can not equalise the pressure within the airlock during the exit cycle to the Loulan atmosphere pressures. Without equal pressures you can not prevent wind currents from occurring when opening airlock doors. The active vent has no effect when the external pressure within the airlock surrounding the active vent is already >101kPa. When the pressure is <101kPa the vent will stop when it reaches 101kPa.

The "PressureExternal" and "PressureInternal" values can be modified using logic chips or programmatically via IC10 scripts.

Note: These values reset to default values on mode change. Values can be set through logic chips, if the value is modified after a mode change.

Note: Switching logic chips off then on will not modify values on the active vent, the values supplied to the chips must be altered for the values to be written.

To calculate the moles per tick, use the following equation:

n = (P * V) / (R * T)

Where:

  • P = Room pressure (or Max pumping rate: 10 kPa/tick into the volume of the grid the vent is in)
  • V = Volume of the grid the vent is in (8000 L for an empty grid)
  • n = Moles per tick
  • R = Gas constant (8.3144)
  • T = Room temperature (Kelvin)

(These do not take into account the constraints imposed by "PressureExternal" and "PressureInternal")

Note: In order to get the proper units out of this calculation you need to use either kilopascal (kPa) and litre (l), or Pascal (Pa) and cubic meters (m³).

Note: The insert slot currently takes any item and seems to have no effect.

Data Network

Mode Values

These lists the values and meanings for the "Mode" property of the Active Vent.

ValueMeaning
0"Outward" mode (Moves gas from the connected pipe network to the surrounding atmosphere.)
1"Inward" mode (Moves gas from the surrounding atmosphere to the connected pipe network.)
ParameterTypeAccessDescription
PowerBooleanReadCan be read to return if the device is correctly powered or not, set via the power system, return 1 if powered and 0 if not
OpenIntegerRead/Write1 if device is open, otherwise 0
ModeIntegerRead/WriteThe mode of the Active Vent.
ErrorBooleanRead1 if device is in error state, otherwise 0
PressureExternalFloatRead/Write"Outward" mode: Maximum pressure of the surrounding atmosphere. The default value is 101.325 (kPa)
"Inward" mode": Minimum pressure of the surrounding atmosphere. The default value is 0 (kPa)
PressureInternalFloatRead/Write"Outward" mode: Minimum pipe network pressure. The default value is 0 (kPa).
"Inward" mode: Maximum pipe network pressure. The default value is 50662.5 (kPa).
LockBooleanRead/WriteDisable manual operation of the Active Vent.
SettingIntegerRead/WriteA variable setting that can be read or written.
MaximumIntegerReadMaximum setting of the device
RatioFloatReadContext specific value depending on device, 0 to 1 based ratio
OnBooleanRead/WriteThe current state of the Active Vent.
RequiredPowerIntegerReadIdle operating power quantity, does not necessarily include extra demand power
PrefabHashIntegerReadThe hash of the structure
PressureOutputFloatReadPressure of the connected pipe
TemperatureOutputFloatReadTemperature of the connected pipe
RatioOxygenOutputFloatReadRatio of oxygen in the connected pipe. A value between 0 (no oxygen at all, or 0%) and 1 (pure oxygen, or 100%)
RatioCarbonDioxideOutputFloatReadRatio of carbon dioxide in connected pipe
RatioNitrogenOutputFloatReadRatio of nitrogen in connected pipe
RatioPollutantOutputFloatReadRatio of pollutant in connected pipe
RatioVolatilesOutputFloatReadRatio of volatiles in connected pipe
RatioWaterOutputFloatReadRatio of water in connected pipe
RatioNitrousOxideOutputFloatReadRatio of nitrous oxide in connected pipe
TotalMolesOutputFloatReadTotal moles in the connected pipe
CombustionOutputBooleanReadIs the pipe on fire?
ReferenceIdIntegerReadUnique Reference Identifier for this object
NameHashIntegerReadProvides the hash value for the name of the object as a 32 bit integer.

Note: The value of "PressureExternal" and "PressureInternal" will be reset to the default when changing modes.

Note: If turned on, the vent will still consume energy when the target pressure is reached.