Fire Rated Hollow Metal DoorsFire rated hollow metal doors and frames are an essential part of any commercial building. They provide safety to pedestrians in case of a fire by preventing the spread of the fire throughout the building. Fire resistant walls, doors, and frames compartmentalize the building allowing it to deter the spread of smoke and fames. The fire door assembly protects the openings in these fire walls. Building codes such as the IBC (International Building Code) includes the requirements for fire rated walls and doors. However, requirements and codes can vary every year, so it is always best to stay up to date with all building codes.
Common Fire Rated Door LocationsStairwell Doors
So what are the most common locations for fire rated doors? Believe it or not, stairwell doors are the most popular fire rated hollow metal doors. Stairwell doors are essential to the fire protection of any building if you think about it. Stairwell doors protect the entire stair enclosure as a means of egress. As an example, if there is a 5 story building and there is a fire on the 3rd floor, all pedestrians would escape through the building using the stairs. It is vital that the 3rd floor door is fire rated, so it can protect the stairwell from the fire. It the 3rd floor door was not fire rated, the stairs could potentially be engulfed in flames, causing the pedestrians on the 4th and 5th floor to be trapped. From this example you can see just how important fire rated doors are. In some buildings where sprinklers do not exist, 450 degree temperature rise fire doors may be required. Either way the importance of reduced heat transfer with fire rated doors plays a large role in building evacuation safety.
Residential Corridor Doors
Another important location of fire rated hollow metal doors are any type of residential corridor door ways. Examples include hotel room doors, apartment building doors, or college dormitory doors. Having fire rated hollow metal doors in these applications are important because they help protect the hallway or corridor as a means of evacuation in the event of a fire. As an example, if fire occurs in an apartment building, the residents of the entire floor will need to evacuate. If the room with the fire has a fire rated door, it can help deter the smoke and flames, allowing the entire floor to escape using the hallway and exit the building. Most hotels, apartments, and dorm rooms have fire rated front entry doors.
Incidental Use Doors
An incidental use door is a doorway that is more proned to a potential fire hazard. These rooms might be electrical rooms, furnace rooms, boiler rooms, refrigerant machinery rooms, incinerator rooms, paint shops, laundry rooms, etc. Since these room types are at a higher risk for potential fires they are often surrounded by fire walls with fire rated doors and frames. Building codes specify which rooms require fire walls and doors.
Opening Fire Protection Assemblies, Ratings and MarkingsThe building code defines the fire resistance rating for the wall. Below is table 716.5 from the 2015 International Building Code.
NFPA 80 National Fire Protection AssociationIf you have been researching fire rated doors, you may have come across the NFPA or National Fire Protection Association. This non profit organization began in 1896 with a sole purpose of eliminating damage and harm caused by fire or electrical related hazards. The NFPA 80 is the standard for fire rated doors. It is referenced by the International Building Code (IBC), the International Fire Code (IFC), NFPA 101 The Life Safety Code, and other code requirements. The NFPA covers a wide range of fire protection, in regards to fire rated door assemblies, chapter 6 pertains to all swinging doors with builders hardware.
Opening ClassificationsThe NFPA 80 created a set of classifications for openings protected by fire doors using a letter designation:
Class A openings are in fire walls and in walls that divide a single building into fire areas.
Class B openings are in enclosures of vertical communications through buildings and in 2 hour rated partitions providing horizontal fire separations.
Class C openings are in walls or partitions between rooms and corridors having a fire resistance rating of 1 hour or less.
Class D openings are in exterior walls subject to severe fire exposure from outside the building.
Class E openings in exterior walls subject to moderate or light fire exposure from outside the building.
Opening ClassificationFire doors and frames are classified by the number of minutes they have been tested to withstand fire:
As an example a class B door, such as a stairwell door, could be classified as a 60 minute or 90 minute door. The fire rating is shown on the label placed on the hinge side of the door and frame.
- 180 minutes
- 90 minutes
- 60 minutes
- 45 minutes
- 20 minutes
The fire rating of the door is typically less than the fire rating of the wall. This is because the "fuel load" adjacent to a door is typically lower than the fuel load against a wall. When we say fuel load we are referencing any object or material that can help fuel a fire. Fire doors that are no longer in use should be replaced with a construction equivalent to the wall rating. For example, the photo below illustrates a cabinet that been placed directly in front of an unused door which would increase the fuel load.
Hollow Metal Door Components or HardwareAll door hardware used on fire rated hollow metal doors must be listed by testing laboratory as approved for fire rated doors. Popular testing laboratories include UL (Underwriters Labratories), WHI (Warnock Hersey), ETL. All testing agencies have their own mark which indicates to the public that the product is in compliance with accepted national standards.
Fire Rated Door PerformanceIn the event of a fire, all fire doors must be closed and and latched to provide fire protection. This means that fire rated doors are outfitted with a fire rated door closer device, and a fire rated lock type. The illustration below shows a fire rated door being held open by a garbage can. This is a very bad practice because in the event of a fire the smoke would flow through this open door and fuel the fire.
As an example the below illustration on the left shows a fire rated door. As you can see it was able to deter the smoke and flames and keep them at bay on the inside of the room. The second illustration below on the right shows the inside of the room where the fire occurred. As shown in the illustration, fire rated doors can deter fire and smoke, and be the difference in saving lives and maintaining the least damage as possible during a fire.
Fire Rated LabelsAll fire rated labels must remain visible and legible. This is so that building inspectors and other personnel can identify the door as meeting the proper specifications. Each fire label includes data such as the rating, test methods, required latch throw, smoke resistance, and issue number. Below is an illustration of a 3 hour fire label.
Construction LabelsA construction labels are similar to fire rated labels but are primarily used on oversized doors and frames. Typically construction labels are used when a design calls for a door or frame that has not been tested. Construction labels have to be approved by the Authority Having Jurisdiction (AHJ). Essentially, a construction label states that the door or frame is constructed of the same materials and methods as a listed product.
Fire Rated Hollow Metal Door TestingAll fire rated doors go through a lengthy testing process. The test itself works to replicate a real world fire. The door is installed in large test furnace which replicates the effects of a real fire.
The International Building Code (IBC) lists opening protectives that require fire doors to be tested to UL10C or NFPA252 with a neutral pressure plane at 40 inches above the floor after 5 minutes. This is called the positive pressure test method. Positive pressure tests is the most accurate test that replicates a real world fire.
After every fire test, the fire door goes through another test called a hose stream test. This test is not typically required for 20 minute fire rated doors. The test involves a real world fire hose that is sprayed on the doors.
Fire Protection vs. Fire ResistanceFire protected assemblies are UL10c or NFPA 252 compliant. Whereas Fire resistance rated assemblies are UL 263 or ASTM E119 compliant. You might be asking what is the difference. Fire protection rating transom and sidelite frames for hollow metal doors are not permitted in some locations. Instead these locations require fire resistance frames with a rating equal to the rating of the fire wall. Table 716.5 from the 2015 International Building Code shows the location where fire protected transom and sidelites are not permitted.
Table 716.5 from the 2015 IBC also shows locations where fire protected assemblies are permitted.
Fire Rated Door HardwareAny fire rated door must also have hollow metal door hardware components that are fire rated compliant as well, this includes a variety of door hardware door closers, locksets, and more that must meet specific fire code compliance. To learn more about fire rated door hardware please visit our hollow metal door hardware section.