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A fire door is a type of door, or closure used as a passive fire protection item within buildings to prevent the spread of fire. It is usually the only means of allowing people to pass through a fire-resistance rated wall assembly. It is made of a combination of materials, such as steel, gypsum, vermiculite-boards, which, together, form a system. Apart from the door leaf, there is the doorframe, the door hardware and the structure that holds the fire door assembly in place. All are required by law to adhere to bounding requirements in product certification that is acceptable to the local Authority Having Jurisdiction (AHJ). Door hardware includes, but is not limited to, manual or automatic closing devices, locks, and latches. Some fire doors are equipped with internal windows, which must, likewise, have a rating or have been incorporated at the time of the door test and be subject to product certification. Fire-resistive windows may include wire mesh or liquid sodium silicate to perform well under fire conditions and/or to provide impact resistance. Wired glass typically withstands the fire, whereas the sodium silicate liquid also acts to reduce heat transfer, due to the endothermic action of this chemical. Fire doors are not necessarily all noncombustible. A fire door is but one of many passive fire protection components used to compartmentalise fire and thus keep it in the compartment of origin, so either it runs out of fuel or it is extinguished, or, at the very least, enough time has been bought to enable evacuation of the building. Fire doors are routinely defeated by unwise actions and apathy on the part of their users, many of whom paint over and/or ignore the product certification markings that are prominently displayed both on the door leaves and all the fire door frames, by blocking them open and even running carpets through them. Such extreme neglect is the responsibility of the owner, who must educate occupants on the safe use of all safety related items, to ensure compliance with the fire code.
Most fire doors should be kept closed at all times, however some are designed to stay open under normal circumstances, only to shut automatically or manually in the event of a fire. Whichever method is used, the door's movement should never be impaired by a doorstop or other obstacle. Proper bounding of fire doors should be routinely checked and ensured.
Some fire doors are held open with an electromagnetic coil, which may be wired to a fire alarm system via relays. If the power fails or the fire alarm is activated, the power to the coil is cut and the door closes on its own.
Rated fire doors are tested to withstand a fire for a specified period. There are 20, 45, 60 and 90-minute-rated fire doors that are certified by an approved laboratory (i.e. Underwriters Laboratories).
The building trade typically responsible for door installations is the Carpenters. In building design drawings with poor identification of which walls do in fact have a fire-resistance rating, it is often necessary to check the door schedule to be able to trace what walls are rated and how long they are rated for. This is an indicative sign about the architect and the degree of care taken particularly with items relating to passive fire protection.
External links
"Fire door"