Fires slowly damage crew and systems in the room, and also consume oxygen. The more fires in the room, the faster the crew damage, system damage, and oxygen depletion. Rock crew are immune to fire damage. When fires completely burn down a system, they also deal 1 point of hull damage.
Many weapons and drones have a chance of causing fires, but some have a much higher chance -- especially the Fire Beam, Fire Bomb, and Fire Drone.
The speed of fire spreading is randomised. Fires can quickly get out of control, especially in a four-tile room.
Tips for dealing with fires
- Send crew members in to extinguish the flames. Most races extinguish fire based on their repair skill, so Engi are the fastest fire-fighters. Rock crew have a hidden 67% bonus to fire-fighting, as well as immunity from fire damage. Lanius may be helpful when venting a room, but they will still take damage from fires. Crystal crew have a hidden 17% penalty to fire-fighting.
- Vent the room. Venting is faster with multiple airlock doors, and also faster if you turn O2 off.
- Upgraded doors greatly slow the spread of fire from room to room.
- Repair drones, when powered, will automatically head towards a room on fire to put out the flames. Repair drones take no damage from fires.
- Fire Suppression (Advanced Edition content) automatically puts out fires on board the ship.
- It is possible to prevent fire from damaging your hull by launching a Small Bomb or Breach Bomb at the burning room. Destroying the system prevents the hull damage that would otherwise occur when the fire burns it down completely.
Enemies behave quite predictably when fires occur on their ship. They treat fire as a high-priority task, and will generally send two crew members to fight it. Weakened crew will flee from fires. Enemy ships are unable to use venting to deal with fires.
If a 2x2 room is completely filled with fire (all four tiles have a flame on them), enemy crew will give up and leave the room (except for Rocks).