The reason for the fire resistance of fire doors is very simple, mainly the use of inorganic non-combustible materials other than steel, refractory wood or refractory wood products.

https://ztfiredoor.com/20773.html

fire rated entry doors,sliding fire doors internal,fire resistant garage door,steel fire rated entry doors,30 in fire rated door,fire rated doors for homes,fire rated entry doors,1 hour rated access panel,fire resistant garage door,30 in fire rated door,sliding fire door kitchen,fire rated entry doors,32 inch fire rated door,fire resistant garage door,fire rated garage door with window,30 in fire rated door