Fire Rated Doors and Frames
There are some basic requirements for an opening before it can be classified as fire rated:
The wall, frame, and door all have to be fire rated. This is self explanatory as it would not make much sense to put a labeled door in a non rated
wall just as you can't put a non labeled door in a rated wall and call the opening fire rated. The purpose of a fire rated opening is to retard fire for
a specific period of time (see below for different ratings) so all components of the opening will have to be rated.
The door must be self closing. If the door is left open during a fire, then that opening cannot retard the fire as it was meant to do, so the door
has to close after somebody passes through it. This is usually done by a door closer or, in some cases, spring
hinges. Both serve the same purpose in that the door will close and serve its purpose of holding back the fire.
The door must be self latching. Push and pull plates cannot be used on a fire rated door.
The door has to latch into the frame when closed so it stays shut until it is manually opened.
This prevents the door from opening during a fire if something falls against it.
This means that you have to use at least a passage set on the door.
Steel ball bearing hinges must be used. Brass, bronze and other bases cannot be used.
The hinges must have a steel base on fire rated doors. Plain bearing
hinges cannot be used as well. Ball bearing hinges ensure the door will not come loose from
the frame and fall out of the opening.
As stated above, the purpose of a fire rated opening is to retard fire for a specific period of time. Most labeled doors will have an A, B, or C label:
A label: 3 hour rating (for a 4 hour wall). These doors are used for openings in walls separating buildings that are joined together. No glass is
allowed in these doors.
B label: 1 1/2 hour rating (for a 2 hour wall). These doors are usually used for stairwell doors but are sometimes used at all the rated walls in a
building. 100 square inches of exposed glass is allowed.
C label: 3/4 hour rating (for a 1 hour wall). These doors are used for openings from a corridor into another room in the same building. 1296 square
inches of exposed glass is allowed.
Louvers can be installed on
fire rated doors but they have to be fusible link. This means that once the heat from the fire
reaches a certain temperature (usually 105 degrees), the fusible link will melt which causes
the louver blades to close . This will help prevent the spread of fire. The maximum size for
these louvers is 24 x 24. There is no glass allowed in a fire rated door if it has a louver and
no louvers at all can be installed in a 3 hour rated door.
Stairwell doors have to be fire rated but they will also
have to be rated as the temperature rise type if the building is 4 stories or higher. This means that the temperature
on the stairwell side of the door can't get over a certain amount during the first 30 minutes of a fire.
Remember to follow the requirements listed above. Codes differ from area to area but these are the standard.
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