create an init.sqf file with this code in it.
BIS_Effects_Burn=compile preprocessFile "\ca\Data\ParticleEffects\SCRIPTS\destruction\burn.sqf";
then in the objects init put
nul = [this,5,time,false,false] spawn BIS_Effects_Burn;
You may need to place a function module on the map.
how it works
//nul=[unit,intensity,time,lifecheck,fade] spawn BIS_Effects_Burn
//Unit: the name of the object that the fire will be attached to
//Intensity: the intensity of the fire. Recommended to use values between
//0.8 and 10, higher values may be used if desired though.
//Time: the time that the fire started. use global variable "time". Used to keep effects synced for JIP
//Lifecheck: if this is true then the unit will only burn as long as it is dead (!alive unit).
//Set to false to burn things like buildings and gamelogics
If it doesn't burn forever try changing the first false statement to true.