The formation of fire consists of oxygen + heat (spark) + flammable
materials. in order to put out the fire, at least one of these three factor
must be destroyed or separated from the others. Destroying or separating the
flammable materials is really hard except special conditions. Thus, other two
factors are used to extinguish fire. Cooling and/or strangling method are used
in order to extinguish except petroleum and electricity fire.