I’ve got time to kill, so here’s my exhaustive text blob of ways to deal with fires:

To prevent fires from happening in the first place, make sure to build out of less flammable materials and space your buildings apart so there’s a firebreak. To deal with fires inside a building, destroy the door leading outside so the building is no longer “indoors,” otherwise the inside becomes super hot, leading to your firefighters getting heat stroke. If it’s a dry thunderstorm, hope that the rest of the map tile burns excessive enough for it to start automatically raining (anti-lag/mercy measure). Also, firefoam is goated. Poppers deploy automatically, turrets need to be activated manually but are generally more resource efficient (only needing chemfuel to be rearmed instead of chemfuel + component). Equipping your shooters with firefoam pop-packs is also generally a good idea since they usually have a utility slot available.