Fire/Smoke/Egress Doors
To allow for better understanding, here are a couple of definitions, and explanations. (using Florida Building Code 2017)
I am not adding ALL of the definitions, but these pertain to the explanation of the doors.
Area of Refuge is an area where persons unable to use stairways can remain temporarily to await instructions or assistance during emergency evacuation.
Exit Passageway is an exit component that is separated from other interior spaces of a building or structure by fire resistance-rated construction and opening protectives, and provides for a protected path of egress travel in a horizontal direction to an exit or to the exit discharge.
F Rating is the time period that the through-penetration firestop system limits the spread of fire through the penetration when tested in accordance with ASTM E814 or UL 1479.
Fire Barrier is a fire-resistance-rated wall assembly of materials designed to restrict the spread of fire in which continuity is maintained.
Fire Door Assembly is any combination of a fire door, frame, hardware and other accessories that together provide a specific degree of fire protection to the opening.
Fire Partition is a vertical assembly of materials designed to restrict the spread of fire in which openings are protected.
Smoke Compartment is a space within a building enclosed by smoke barriers on all sides, including the top and bottom.
Smoke Barrier is a continuous membrane, either vertical or horizontal, such as a wall, floor or ceiling assembly, that is designed and constructed to restrict the movement of smoke.
Through-Penetration Firestop System is an assemblage consisting of a fire-resistance-rated floor, floor-ceiling, or wall assembly, one or more penetrating items passing through the breaches in both sides of the assembly and the materials or devices, or both, installed to resist the spread of fire through the assembly for a prescribed period of time.
Building Types have a significant amount of information that lists different material, requirements, fire resistance rating requirements, and more. It varies widely by state, jurisdiction, and municipality. It is legitimately it’s own flurry of pages, but because it is not specifically required for this explanation, feel free to investigate your particular state’s construction code.
To maintain the rating of the walls, or barriers, all penetrations, including fire door assemblies are required to adhere to a certain set of standards.
Fire door assemblies are used for the openings in fire walls, and fire barriers. The lowest rated item that is attached, or used within this assembly is the entire assembly’s rating.
For example, if everything on the door is 3 hours, but you add a non-rated door stop, the rating of the entire assembly is now 0 hours. Or if you add a 1 hour rated handle (without the door stop), it would then be 1 hour for the entire assembly.
For fire walls, they have to be 3/4ths of the rating of the wall (with exceptions). One of those exceptions is that the wall below a fire sprinkler system can be 1/2 of the rated wall, as long as above the covered portion of the wall which is usually sectioned off by the drop ceiling maintains the rating of the wall.
For example
A 2 hour fire wall has to maintain the 2 hour rating above the drop ceiling, while below the drop ceiling it can be 1 hour rated as long as it’s covered by a fire sprinkler system (riser). The fire door can be 45 minutes because it’s maintaining the 3/4ths requirements of the surrounding wall. (left image)
However, without the fire sprinkler system, the fire rating must be maintained from top to bottom. That means the fire door must be 1 1/2 hour. (right image)
Smoke doors require a gasket around the edges of the door opening, this helps maintain a blockage of the smoke from making it through the door opening. A smoke door is only going to be on the penetration of a smoke barrier, or smoke compartment area.
Smoke doors are usually rated to be 20 minutes of a fire rating, but this is not guaranteed. If you place a normal smoke door assembly within the penetration of a fire barrier, the wall cannot be rated for more than 30 minutes. You must adhere to the ratings of the wall listed on the plans.
Egress doors and more will be added soon.