Fire Rated Door Labels / Ratings

Fire rated doors are used in buildings to prevent the passage of fire and smoke between two compartments or areas. They are used as a passive means of protecting people and property from fires. Model codes in the United States generally reference NFPA 80: Standard for Fire Doors and Other Opening Protectives when it comes to installation and maintenance of fire doors.

The International Building Code and International Residential Code require that doors and frames be given a fire-resistance rating after extensive testing by an approved agency. There are a number of testing agencies in the United States, but some well-known agencies that test and certify fire doors include Underwriters Laboratory (UL), Intertek Testing Services (Intertek ETL), and QAI Laboratories, LTD (QAI). Doors are tested following standards, including UL10B, UL10C, ASTM E2074, and NFPA 252.

Once tested, the door and frame receive a label that describes the amount of time the component is expected to provide protection when exposed to fire. When combined, all of the components of the door form an assembly that protects the opening. For this reason, all components of the door must include a rating label, including the door panel, the door frame, locksets, gaskets, hinges, and door protection plates. In other cases, the entire assembly (including all hardware) has a single rating.

A permanent label is attached to the door panel and the door frame, usually on the hinge side of both. Most other components have a testing agency symbol formed or stamped into the material to identify that the testing agency confirms the components meet the testing requirements.

Example UL Door Label
Example UL Door Label
Example QAI Door Label
Example QAI Door Label
Photo of an Intertek door label mounted to door frame at left and mounted to door at right
Intertek door label mounted to door frame at left and mounted to door at right

Local codes should be reviewed, but in general, rated doors must be self-closing and must have a positive latch. There are also limits to the size of glazing in the door, the width of gaps between door panels, the height of the door under-cut, and the size of air transfer grilles.

Chart of Door Ratings and Labels

As mentioned above, doors are labeled based on the amount of time (in hours or minutes) the door is expected to provide protection. Some very old doors may have a letter-rating, which corresponds to the time-based ratings. We include the letters in our chart below for reference, but the time-based ratings should be used on current projects.

4 HR240 MIN----
3 HR180 MINA100 square inches per leaf
1 1/2 HR90 MINB100 square inches per leaf**
1 HR60 MIN--1296 square inches per lite**
3/4 HR45 MINC1296 square inches per lite**
1/3 HR20 MIN--1296 square inches per lite**

** Limited to the maximum area tested

Labels D and E were used for exterior doors that are subject to fire hazards from the outside of the door; however, these are no longer used.

Temperature-Rise Rating

Doors may also have a Temperature-Rise Rating in number of degrees. This represents the expected surface temperature on the unexposed side of the door after 30 minutes of fire exposure. You will see this marked as 250°, 450°, or 650°. Glass included in the door must also meet the temperature rise requirements.

S-Label or "Smoke Rating"

Many codes require an S-Label for certain doors in some occupancies. For instance, corridor doors often require smoke protection to prevent smoke from leaking from or into an occupied space.

An S-label isn't exactly a "smoke rating". Rather, the S-label indicates the door meets the leakage tests that are part of UL 1784: Standard for Air Leakage Tests of Door Assemblies and Other Opening Protectives. However, smoke cannot pass through if air cannot leak through the door assembly. An S-label is usually achieved by installing UL approved gasketing.

Required Door Ratings Based on Partition Rating

The required door rating is based on the rating of the partition or barrier that the door is in. The table below provides an overview, but the building code should be referenced due to the complexity involved in determining the rating of the partition and the type of opening allowed. Table 716.5 in the International Building Code provides a detailed list of requirements. Local codes may vary.

Fire Wall / Fire Barrier4 HR180 MIN
Fire Wall / Fire Barrier3 HR180 MIN
Fire Wall / Fire Barrier2 HR90 MIN
Fire Wall / Fire Barrier1 1/2 HR90 MIN
Fire Barrier Having a 1 HR FRR*1 HR60 MIN
Other Fire Barriers1 HR45 MIN
Fire Partitions (Corridor Walls)1 HR20 MIN
Fire Partitions (Corridor Walls)30 MIN20 MIN
Other Fire Partitions (Non-Corridor Walls)1 HR45 MIN
Other Fire Partitions (Non-Corridor Walls)30 MIN20 MIN
Exterior Walls3 HR90 MIN
Exterior Walls2 HR90 MIN
Exterior Walls1 HR45 MIN
Smoke Barriers1 HR20 MIN

* Enclosures for shafts, exit access stairs, exit access ramps, interior exit stairways and ramps, exit passageway walls.

Fire Rated Door Field Modifications

Field modifications of a fire rated door require specific knowledge of the codes and should be performed by a person qualified to work on rated openings.  NFPA 80 provides specific guidance on what can and cannot be done to a rated door. It is important to confirm that all new components have a label that matches the rating of the existing door and frame. In addition, the laboratory that initially approved the assembly must also approve the field modifications in writing per NFPA 80-2019 (5.1.5).

Fire Rated Door Annual Inspection

In the United States, NFPA 80-2019 (5.2.4) requires that fire rated doors be inspected each year to confirm that the door is in good condition and that all of the required components work as required. The building owner is responsible for having the inspections done by qualified person and for maintaining proper records of the inspections.

Refer to the codes applicable to your specific jurisdiction for label or rating requirements.

Help! My Door Needs A Label

Archtoolbox does not provide professional services. If you have a door that is missing its label, you should reach out to a local company that can help you. You can try a Google search for door field labeling services.

There are three nationally known agencies in the United States that may offer local field testing services: Intertek, QAI, and Underwriters Laboratories.

Article Updated: December 10, 2022
  • Matt Lansdowne, P.Eng., M.Sc.

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