A fire door is a door with a fire-resistance rating used as part of a passive fire protection system to reduce the spread of fire or smoke between compartments and to enable safe egress from a building. Generally, fire doors may be made of a combination of materials, such as:

• Glass sections
• Gypsum (as an endothermic fill)
• Steel
• Timber
• Vermiculite-boards
• Aluminium​​

Both the door leaf and the door frame must respect the requisites furnished by the agency which attests the products. All the components of these doors form an assembly, typically called a "doorset" which holds a numerical rating, quantified in hours of resistance to a fire test. 

SEALS
Edges of a fire door usually need to have fire rated seals which can be composed of:

• An intumescent strip, which expands when exposed to heat
• Neoprene weatherproof stripes
• Garnishes to prevent the passage of smoke                                                                          

Seals may vary in chemical composition, expansion rate, expansion volume, and/or charring characteristics.

WINDOWS
Some fire doors are equipped with internal windows which also have a rating, or have been incorporated at the time of the door test and subject to the door's product certification. Fire-resistive windows must remain intact under fire conditions and can include: