Beyond Apex

Fire-rated doors are needed to be certified via independent laboratories such as Underwriters Laboratories, Inc., to earn their official fire rating. Depending on how all elements of the assembly perform during the various tests, fire-rated doors can acquire a fire-protective or fire-resistive certification for a particular time range. To develop fire endurance, hose stream tolerance, temperature increase as well as smoke and draft control skills, fire-rated glass doors must pass various rigorous test such as:

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1. Fire Endurance Test

To achieve UL 10B requirements, a massive furnace exposes the assembly to temperatures up to 1925 degrees Fahrenheit according a prescribed heat temperature curve. The fire test assesses the period of time, in minutes or hours, that the fire-rated door or material may remain intact without breaking or letting flames on the non-fire side of the assembly. Upon completion, the material or assembly will earn a rating that corresponds to the test’s duration. For fire-qualified doors that feature rated glass, this normally runs from 20 to 90 minutes.

2. Hose Stream Test

Fire-rated door assemblies or glazing materials with fire ratings more than 20 minutes are submitted to the hose stream test immediately after the fire endurance test. In Canada, all fire-rated glazing materials must pass the hose stream test. To pass the test, the assembly must stay intact following a blast from a fire hose with a nozzle pressure of at least 30 pounds per square inch. Only glass that stays in the frame can obtain a rating greater than 20 minutes. In addition to analyzing the impact and erosion produced by the water, this test also looks at “thermal shock” – how well the heated glass and surrounding frame materials can endure a rapid jolt of cold water. This assists in getting rid of subpar components or structures that could collapse under comparable circumstances.

3. Criteria for Temperature Rise

Temperature-rise doors offer an extra layer of security by preventing heat transmission from one side of the door to the other as well as the spread of smoke and flames. The International Building Code (IBC) mandates this test for fire-rated door assemblies placed in areas of egress to make that people may still pass by a door to leave a building in the event that the fire side of the door experiences extreme heat. Within the first 30 minutes of a fire test, these assemblies must have a maximum communicated temperature rise of 450 degrees Fahrenheit or less to the door assembly’s non-fire side.

Additional Testing

In addition to fire ratings, doors can pass other tests to get the necessary performance ratings. Common tests related with fire-rated doors include the positive pressure test (UL 10C), which more closely replicates real fire conditions, and the smoke and draft control test (UL 1784), where the air leakage rate of a door assembly is measured at ambient and increased temperatures. Additionally, the National Fire Protection Association (NFPA) publishes tests, such as NFPA 252 and NFPA 80, for doors that are fire-rated.

Additional testing for fire-rated doors evaluates resilience to impact, hurricane, gunshot, and forced entry, among other things. While it’s crucial to understand the tests that fire-rated doors must pass, architects may also satisfy code requirements and create visually stunning designs by learning how these assemblies can be employed throughout the building environment.

DOES A FIRE DOOR REQUIRE A SPECIAL DOOR FRAME?

To comply with code, every component of a fire door—including the frame and jamb—must be fire rated. The International Building Code (IBC) mandates that all components have the same or higher ratings and degree of fire protection than the necessary code minimums in order to guarantee the assembly functions as intended.

The location of a fire door within a structure will determine the frame’s particular rating. Fire door assemblies with frames certified for ninety minutes, for instance, would be necessary for walls dividing a structure that are fire rated. Codes may stipulate that jambs for stairway enclosures must be fire-resistant for 60 to 120 minutes. This keeps egress routes open by preventing heat transfer and according to temperature increase door requirements.

Since places are free to adopt (and modify) alternative model codes as well as earlier editions, requirements can also range greatly. Therefore, it is advised that specifiers speak with an Authority Having Jurisdiction (AHJ) to explain fire door requirements.