What Do Fire Door Ratings Mean?

Fire Doors serve two purposes in a commercial building. They provide safe passage out of the building in the case of a fire, and they help keep a fire from spreading to other parts of the building, and help reduce smoke hazards that can stop those inside from leaving the building.

The labels on fire doors include a rating – ranging from 20 minutes to three hours – which indicates how long that door can withstand fire and heat under test conditions.

So one might ask, “Why are there different ratings? Wouldn’t I want three-hour Fire Doors everywhere?” It’s not that simple.

The ratings on Fire Doors are based on what the door’s purpose is, and where they are installed – and each level serves a specific purpose in helping people inside a building to escape:

1)      Three-Hour – You will find a three-hour fire door installed in a wall that separates two buildings. However, in larger buildings, a three-hour door may also be used to provide access among smaller areas within the building.

2)      90-Minute – The two most common areas where you will find a 90-minute door are on an exterior wall where there may be severe fire exposure on the outside of the building; or in stairwells, where people may be trying to escape from upper floors. Think of the signs you see that say to use the stairs in case of fire. That is because they are very well protected from fire outside of those doors.

3)      One-Hour – These fire doors are typically found between rooms within the same building.

4)      45-Minute – Fire Doors rated for 45 minutes are typically found in walls that serve as room partitions, as well as corridor walls. Some exterior fire doors where there may be moderate fire exposure outside may also carry this rating.

5)      20-Minute – These fire doors are mostly found in hallways, and serve the primary purpose of controlling smoke and drafts while people make their way out of the building.

A Warnock Hersey Certified Door Inspector can offer more insights on the proper ratings for Fire Doors, and also ensure that they are labeled properly and in good working order. For more information on Fire Door labeling, call the Door Code Inspection Service at (614) 634-1976.

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