Hollow Metal Doors and Frames Fire Rating Checklist

July 27, 2023

Fire-rated hollow metal doors and frames provide immense value to commercial building projects since they help slow the spread of a fire. It’s a large part of why building codes across the country require fire-rated doors. While hollow metal offers one of the longest and most reliable fire ratings of any door material, we want to further break down the process of achieving this.  

Let’s take a look at a checklist you can use to understand the details behind fire ratings for these essential building products.  

Fire Rating Details You Need to Know

To get the full picture of what a fire rating means, it’s important to know that hollow metal doors and frames must:  

  • Meet the Fire Rating Requirements: To get a fire rating, the steel doors and frames need to be tested by an independent third-party agency. All fire doors also must be self-closing and equipped with positive latching.  

  • Align with the Wall Fire Rating: The required fire rating for any door and/or frame in a commercial building is determined by the fire rating of the wall. The rating for a wall considers a variety of factors such as what the building is used for, the location of the wall, the interior design of the space, and more.  

  • Achieve One of the Five Different Ratings: Hollow metal doors and frames have five main ratings which are 20 minutes, 45 minutes, 1 hour, 90 minutes, and 3 hours. The fire rating of a steel door assembly is determined by the specific component of the door assembly with the lowest individual rating.  

A Breakdown of Different Fire Door and Frame Ratings

In most cases, steel doors and frames are given a fire rating based on the amount of time they can stand up to a fire in standardized test conditions. Let’s take a closer look at the different types of fire ratings with the checklist below:  

  • 3-Hour Fire Ratings: Steel doors and frames that meet the three-hour rating are openings in a wall that divides one building from another. In other cases, the opening separates a big building into more localized fire areas.  

  • 90-Minute Fire Ratings: An opening that uses a steel door and frame to enclose a vertical section of a building like an elevator shaft or staircase area. It’s also common for exterior walls to use these doors to help the building withstand exposure from a fire outside.  

  • 1-Hour Fire Ratings: Paired with walls that also have a one-hour fire rating, these doors and frames commonly divide occupancy areas.  

  • 45-Minute Fire Ratings: Also paired with one-hour rated walls, 45-minute steel doors and frames are commonly used as room partitions. Entryways with this rating are also put in on the exterior of a building if there’s a fire exposure risk from the outside.  

  • 20-Minute Fire Ratings: 20-minute doors and frames are most commonly used for corridors or areas of a building where smoke control is a top priority.  

The Core Types of Fire-Rated Steel Doors

Fire-rated hollow metal doors are often equipped with different types of core materials. While all five of the most common cores can be fire-rated, look at the checklist below for more details on their special use cases.  

  • Polystyrene: This core is made up of foam which helps insulate the opening against temperature and sounds. Polystyrene cores can achieve a fire rating of up to three hours and are often used for exterior entryways on commercial building projects.  

  • Honeycomb: For this core type, cardboard is made into a honeycomb shape and then gets hardened with resins. Given how durable these cores are, you’ll often find them used in heavy-duty commercial applications like interior doors in hospitals.  

  • Polyurethane: This type of foam is injected into the core of the steel door. While it provides one of the highest levels of insulation, polyurethane can’t achieve a fire rating like many of the other core types.  

  • Mineral Core: Mineral cores are lightweight and designed with a noncombustible material to help prevent the spread of a fire. It’s a popular core choice for doors and entryways that are required to have a fire rating.  

  • Steel Stiffened: Steel stiffened cores have welded steel channels that are put in through the full length of the door. These cores can be fire-rated for up to three hours and are a great option for any entryway that is subject to heavy use.  

Learn More About Fire-Rated Steel Doors with HMMA

If you’re looking to learn more about fire-rated steel doors and frames, HMMA is here to help. We have a variety of resources from specifications to continuing education courses. Learn more about why hollow metal doors and frames are some of the best options for fire-rated entryways today.