Fire

Why doesn't these stupid colonist put out the fire!?

There are several reasons to why the colonists are ignoring a fire:

This is what's causing the problem.
- This is how to solve the problem.

The fire is outside a Home zone
- Add a Home zone over and around the burning area

The fire is outside of colonists' allowed area.
- Ensure that at least one colonist has an allowed area that includes where the fire is.

The priority to fight fire is lower than something else
- Increase the firefighting priority for your colonists in the Overview menu.

There are a colonist somewhere on the other side of the map that wants to extinguish this particular fire.
- Draft the "far away" colonist,
- Mark a "near fire" colonist,
- Right click on the fire and choose "Prioritize firefighting",
- Undraft the "far away" colonist.

The colonists are currently doing other stuff.
- Mark a desired amount of colonists
- Draft and undraft them, this will reset their current task and will make them search for other things to do, if the priority to fight fire is high enough they will go and extinguish it, otherwise they will do other stuff.

Things that cause fire

Lightning

Periodic lightning strikes can and will cause fires, although these tend to happen in rainy thunderstorms, which means the fire is generally put out quickly by the downpour. If you ever experience a "Dry thunderstorm", however, be very cautious about lightning, because there will be no rain to fight off the fires for you...

Short circuits

Leaving charged batteries outside in the rain, or having an electronic device like a Sun Lamp turned on when its raining will quickly lead to a short circuit, causing a hefty amount of damage to said device and starting a decent-sized fire in the process. The rain tends to put out the fires, of course, but still, it's best to keep your electronics under a roof at all times.

Weapons

Incendiary launcher
Molotov Cocktail

Sparks

Sparks from a fire causes another fire if they land on something burnable. (Unconfirmed: is it 100% chance that a fire will start if this happen or is it a chance that it happens?)

How To Combat Fire

The most effective way of combating large fires are weirdly enough by using Frag Grenades!

By Using Explosions

Fires that are caught in the explosions are extinguished.

Frag Grenades: Equip a colonist with frag grenades, draft him and order him to throw the grenades at the fire, 1 grenade can put out a 3x3 area.

WARNING! Do not throw the grenades near any machine because a grenade does 65 damage on each square witch have a potential of delivering 65x9=585 damage!

(Mod: Blasting charge) have the same effect as the frag grenades but have to be built first, uses 35 metal, they have a larger blast radius but are stationary.

By Using Colonists

Create a Home_zone over and around the fire
select one or more colonists
make sure that the colonists have firefighting as the highest priority
toggle the drafting 2 times, (press "R" 2 times), on and off again, this resets their current tasks.
if it didn't work select each colonist individually and right click on the fire and choose "extinguish fire"

Useful uses

Remove Corpses

Like in a crematory
See Molotov_cocktails#Remove_dead_bodies for now (To Be Expanded).

Remove Plants

Plants burn, Molotov cocktails are good to start fires, just don't burn down your base.
See Molotov_cocktails#Remove_grass for now (To Be Expanded).

Damage