Fire doors speaks to what are fire doors, types of fire doors, fire door installation.
These doors have a combustible mineral core and are rated according to the period of time for which they are able to resist specified time and temperature conditions. This is as defined by NFPA 252 Standard Methods of Fire Tests of Door assemblies or as defined by Underwriters Laboratories.
In general, doors within fire resistance rated walls must themselves also be fire rated. However, because doors constitute only a limited area of most walls and because combustible furnishings or materials are not normally located directly in front of door openings, the required fire resistance ratings for these doors is often less that required for the walls in which they are located.
Figures are available online that gives fire resistance ratings for these doors as required by the International Building Code (IBC).
For example, a door in a two hour rated exit stairway enclosure must be one and half hour rated, exit corridors must be one a one half hour rated. A door in a one hour rated exit stairway enclosure must be one hour rated and a door in a one rated exit corridor must be twenty minutes (one third hour) rated.
Doors in walls that are two, three and four hour fire resistance rated, such as those separating uses within a building from one another, must be one and one half or three hour rated. A standardized label is permanently affixed to the edge of each door at the time of manufacture to designate its degree of fire resistance.
The building code requires that these labels not be painted over during construction so that the fire rating of the door can always be verified during subsequent building inspections.
Glass used in these doors must also be fire rated so that it will not break and fall out of the opening for a specified length of time when exposed to the heat of a fire. The maximum size of glass may also be restricted, depending on the fire classification of the door and the properties of the particular type of glass used. Like glass in any door, glass in these doors must also meet the requirements of safety glazing so that if broken, it does not create life threatening shards.