How to determine the required fire protection rating of an opening protective?
Depending on the construction type and use, buildings may be designed and constructed with fire
resistance-rated walls, floors and ceilings for structural integrity as well as to prevent fire and smoke
from spreading throughout the building. However, openings in these fire rated assemblies are necessary
for egress, communication, security, everyday travel throughout the building, and building services and
equipment. Openings in fire rated assemblies must be protected accordingly so as to not compromise
the fire resistance of the assembly in which they are located. Unprotected or improperly protected
openings can void the rating of the wall, floor or ceiling by leaving ways for fire and smoke to spread
unintentionally to adjacent fire compartments.
Fire rated components in buildings have either a fire resistance rating or a fire protection rating. It is
important to understand the difference in the two ratings and to understand how to determine the
required ratings of assemblies both when designing a building and also when determining compliance of
existing installations. Although often used interchangeably, the terms are different.
Fire resistance rating vs. fire protection rating
When a building assembly, such as a fire barrier, is required to be fire rated it must be reasonably
airtight under increased air pressure on the fire side due to heated air expansion and must prevent the
passage of heat and flame for a designated time. Fire barriers also must be capable of withstanding
direct impingement by the fire, as determined by large-scale tests, either ASTM E119 or ANSI/UL 263.
The ASTM E119 and ANSI/UL 263 test standards determine fire resistance ratings, in hours, based on
exposure to the standard time-temperature curve and provide the rating of the construction of the
particular assembly and the actual testing of the assembly in the test furnace.
Assemblies protecting openings, such as doors and windows, located in fire resistance-rated assemblies
must be capable of withstanding the effects of fire, as determined by large-scale tests such as NFPA 252,
NFPA 257, ANSI UL10B, ANSI/UL 10C or ANSI/UL 9. The acceptance criteria for these fire protectionrated assemblies, differ from those for fire resistance-rated construction, such as a wall or floor/ceiling
assembly. The limitation of temperature rise through a fire door is not normally a measure of
acceptance, although it is a measure of acceptance for a fire resistance–rated assembly such as a wall.
Some openings may also be protected with products that have a fire resistance rating where they have
been tested as, and passed criteria as required for walls, floors or ceilings. Fire resistance rating, glazing,
is an example of this. It may be installed and used as a wall in some cases if permitted and tested
accordingly.
Determining the required fire protection rating
To properly protect an opening in a fire resistance-rated assembly, the proper fire protection rating is
required. The following steps should be followed when determining the appropriate fire protection
rating of an opening protective:
Step 1: Determine the required fire resistance rating of the component under evaluation. Components
include, but are not limited to, vertical shafts, horizontal exits, exit access corridors, and smoke barriers.
Codes, such as NFPA 101, Life Safety Code, NFPA 5000, Building Construction and Safety Code, mandate
where a building component is required to have a fire-resistance rating.
Step 2: Utilize the tables, “Minimum Fire Ratings For Opening Protectives in Fire Resistance-Rated
Assemblies and Fire-Rated Glazing Markings”, found in Chapter 8 of both NFPA 101 and NFPA 5000 to
determine the minimum fire protection rating of the opening protective based on the fire resistance
rating determined in Step 1. It should be carefully noted that this table DOES NOT mandate the fire
resistance ratings of components, other provisions in the Code will require it.
Step 3: Confirm through footnotes, other code text associated with the component, and through
occupancy specific provisions, that no further modifications to the general fire protection ratings are
permitted. In some cases, there may be exemptions for some opening protectives in existing
installations or for certain conditions in some occupancies.
Example
Let’s look at an example: What is the required fire protection rating for a corridor door in an exit access
corridor in a new, non-sprinklered, office building?
Per NFPA 101, most new, non-sprinklered, business occupancies require exit access corridors have a
minimum 1-hour fire resistance rating (step 1). Next, by going to the referenced table in NFPA 101
(table 8.3.3.2.2) it can be determined that a 1-hour fire resistance-rated exit access corridor requires a
minimum 1/3-hour, or 20-minute, fire-protection-rated door. It can then be confirmed that no further
modifications are permitted (step 3).
Why can the fire protection rating be less than the fire resistance rating?
The required minimum fire protection ratings of opening protectives are sometimes permitted to be of a
lower rating than the fire resistance rating of the fire barrier in which they are located. For example, a 2hour fire barrier enclosing an exit stair is permitted to have fire doors protected by 1½-hour fire
protection-rated door assemblies. The test procedures on which the ratings are based, discussed above,
are different. Although combustibles placed against a fire resistance–rated wall expose the wall to a
considerable fire challenge, a fire protection-rated door assembly does not usually have combustibles
placed against it, because the opening must be clear to use the door and kept free of obstructions for
proper operation of the door. Such a scenario suggests that, if a door is not to be used and combustible
storage is to be placed at the door opening, the door should be removed and the opening replaced with
solid construction to restore the wall to its required fire resistance rating.
Fire rated components are a critical piece to the comprehensive protection strategy that buildings use to
protect people and the building itself from the effects of fire. The success of passive fire protection
methods such as the use of compartmentation requires careful compliance during design and
installation as well as effective and consistent inspection, testing and maintenance to ensure the system
will perform as intended during a fire.
Building codes require specific building components to have a fire rating. The fire rating can vary from
20 minutes to 4 hours and indicates the ability of a wall, door or floor to reduce the spread of a fire or
the amount of protection provided to structural members to allow safe egress of building occupants.
These requirements have a direct effect on windows and doors installed within a building, as there are
specific limitations on glazing in fire-rated installations.
FOUR TYPES OF FIRE-RATED WALLS
Buildings are constructed with four types of fire-rated walls.
1. Fire walls separate two adjoining buildings.
2. Fire barriers are typically used to separate exits from the occupied areas of a building.
3. Fire partitions are used in corridor walls where an exit access area requires a fire rating.
4. Exterior walls are fire-rated only when the fire separation distance between a building’s exterior
wall is 30 feet or less to a lot line, the center line of a roadway, or another building on the same
lot.
Within the four types of fire-rated walls, fire-rated glazing can be installed as a window, an opening in a
door, or as a glass fire-resistance rated wall. The requirements for fire-rated glazing are given in Chapter
7 of the International Building Code.
FIRE PROTECTION VERSUS FIRE-RESISTANCE
The building code recognizes two types of fire-rated glazing: fire protection-rated, and fire resistancerated.

Fire protection-rated glazing is installed for the purpose of containing fire and preventing the
spread of flames and smoke. Fire protection-rated glazing is not intended to block the
transmission of heat. Fire protection-rated glazing is tested to UL9/NFPA 257 Standard Test
Method for Fire Test of Window and Glass Block Assemblies.

Fire resistance-rated glazing is installed for the purpose of containing fire and preventing the
spread of flames and smoke, and is intended to block the transmission of radiant and conductive
heat. Fire resistance-rated glazing is tested to UL 263/ASTM E119 Standard Test Method for Fire
Tests of Building Constructions and Materials.
HOW TO DETERMINE THE FIRE-RESISTANCE RATING
The steps for determining the fire-resistance rating for a specific application can be illustrated with an
example. Imagine construction drawings indicate fire-rated glass is required in several doors in the wall
of a fire barrier that separates an interior stairway that is part of an exit from the rest of the occupied
space in the building.
1. Determine the type of fire-rated wall. Refer to Chapter 7 of the IBC for the specific wall type:

Fire walls are addressed in Section 706.

Fire barriers are addressed in Section 707. (The example given above is a fire barrier.)

Fire partitions are addressed in Section 708.

Exterior walls are addressed in Section 705.
2. In the example, Section 707 for fire barriers says the fire-resistance rating of fire barriers
separating interior exit stairways must comply with IBC Chapter 10 Means of Egress.
3. Chapter 10 Means of Egress designates:

If the exit stairway connects four stories or more, it must have a fire-resistance rating of not less
than 2 hours.

If it connects less than four stories, it must have a fire-resistance rating of not less than 1 hour.
4. Return to IBC Chapter 7 to the fire-rated glazing table for fire doors, Table 716.1(2), shown
below for reference.

The table indicates if the exit stairway connects 4 or more stories, a 2-hour fire-resistance rated
fire barrier wall requires the use of a 1 ½-hour fire-rated door.

The table also indicates that a 1 ½-hour fire door may include up to a 100 sq. in. view panel of 1
½-hour fire protection-rated glazing.

The table also allows the glass in the door to exceed 100 sq. in. if fire resistance-rated glass is be
used.

The table indicates that the 1 ½-hour fire door assembly may also include fire-rated glass
sidelights and transoms, but those must also be made of fire resistance-rated glazing, not fire
protection-rated glass.

If the exit stairway connects less than 4 stories, a different section of the table indicates the
required 1-hour fire barrier wall only requires a 1-hour fire door. The 100 sq. in. view panel using
fire protection-rated glazing and the use of any larger size glass in the door leaf, as well as any
glass used in transoms and sidelights in the door assembly remain the same, namely that only
fire resistance-rated glass would be permitted.
The same process can be used for all the different types of fire-rated walls, following the steps outlined
above. For assistance with this process, consult with manufacturers or fabricators of fire-rated glazing,
or with the authority having jurisdiction for the building project.
OPENING FIRE PROTECTION ASSEMBLIES, RATINGS AND MARKINGS
FIGURE 1 | FIRE-RATED GLAZING TABLE FOR FIRE DOORS
2-HOUR FIRE BARRIERS
Fire-rated Glazing Table for Fire Doors, from 2021 IBC, Chapter 7, Table 716.1(2). The arrow indicates
the applicable row of the table for 2-hour fire barriers.
FIGURE 2 | FIRE-RATED GLAZING TABLE FOR FIRE DOORS
1-HOUR FIRE BARRIERS
Fire-rated Glazing Table for Fire Doors, from 2021 IBC, Chapter 7, Table 716.1(2). The arrow indicates
the applicable row of the table for 1-hour fire barriers.