Why are fire doors kept closed during a fire? Scientific answer. Is it to prevent?

Question

radiant energy produced by the fire from escpaing?
prevent convection currents from fanning the flames of the fire?
decrease the spread of the fire because conduction the heat ?through the door is slower than conduction of heat by convection through the air?
deprive the fire of oxygen

I need to know which one of these answers I listed best fits the question.

Answer 1

through the door is slower than conduction of heat by convection through the air

Answer 2

It's for purposes when a fire starts, you don't want to spread it around the room, do you? And get in touch with any chemical reactions that spilled to MAKE the fire? Don't think so...
So they keep the fire doors closed so it is to prevent it from spreading everywhere and burning whatever place down... the end =D

Answer 3

Fire doors are designed to be thicker and less flammable. They hold the fire back by their strength and by preventing the spread of the fire by blockage of it's spread.

Answer 4

It is to slow the spread of the fire. Fire doors and constructed of special materials and to meet certain specifications so that they are less likely to be consumed in a fire than other types of doors.

Whole rooms can be built to be fire-retarding or "explosion proof" and it is a standard when building certaing types of buildings.

Answer 5

Fire doors are designed to burn at a certian rate thus slowing the fire , most construction materials carry a burn rating , the time it which it takes to become ''fuly engulfed'' , Fire doors ar a saftey precaution and prevent the spread of fire to other parts of a builing ...

Answer 6

It is definitely to keep the fire from getting oxygen, and that would kill the fire, unless it had already broke through a wall.

Answer 7

That it. because if the door was open then the fire would just spread even futher at leat if the doo is shut then the fore is hopefully contained