This reference guide reflects CDF Distributors’ standard product specifications and fire rating requirements as applied to commercial door and frame assemblies. The information is based on NFPA 80, the International Building Code, and CDF’s fabrication and labeling procedures. CDF has supplied fire-rated door assemblies to commercial projects nationwide from its Nashville, Tennessee headquarters.

Fire rating requirements vary by jurisdiction. Always verify specific code requirements with the project’s design professional and the Authority Having Jurisdiction (AHJ). For questions about fire-rated assemblies or to configure an order, contact CDF at (855) 769-9895 or sales@cdfdoors.com. Configure your assembly online at cdfdistributors.com using ProBuilder.

About This Guide

What does a fire rating mean on a commercial door?

A fire rating indicates the number of minutes a door assembly has been tested to resist the passage of fire and smoke under controlled laboratory conditions. The rating applies to the complete assembly—door, frame, and hardware—not to any single component. All components must carry matching fire labels for the assembly to be code-compliant.

Do all components need to be fire-rated if the door is fire-rated?

Yes. When a door is fire-rated, the frame, lite kits (glass), louvers, and certain hardware must also be fire-rated to the same level. A fire-rated door installed in a non-rated frame does not constitute a compliant assembly. CDF configures complete assemblies with matching ratings on all components.

What is the maximum fire rating for a drywall frame?

Drywall wrap-around frames can be fire-rated up to a maximum of 90 minutes. Projects requiring ratings above 90 minutes must use masonry frames. CDF’s ProBuilder tool automatically enforces this limitation during assembly configuration.

What is the maximum fire rating for a wood door?

Wood doors can be fire-rated up to a maximum of 90 minutes, but only with mineral core construction. Standard wood doors with particleboard core are limited to 20 minutes. For ratings above 90 minutes, metal doors are required.

Can hurricane-rated door be fire-rated?

No. Hurricane-rated doors cannot be fire-rated. These product categories have separate testing and certification standards that are not compatible with fire rating requirements. If a project needs both wind resistance and fire resistance in the same area, consult with CDF’s sales team for alternative solutions.

Why must fire-rated doors be self-closing and self-latching?

Fire-rated doors must close and latch automatically to prevent the spread of fire and smoke through an opening. This requires a door closer and a latching lockset on every fire-rated assembly. Passage-function hardware (non-latching) is not permitted on fire-rated doors.

What is the maximum undercut allowed on a fire-rated door?

Fire-rated doors cannot have an undercut greater than 3/4 inch. An undercut larger than 3/4 inch compromises the fire resistance of the assembly and will not pass inspection.

How do I know if a door or frame is fire-rated?

Every fire-rated door and frame must have a physical metal fire label riveted to it. CDF rivets fire labels onto all fire-rated doors and frames before shipping. If a door or frame does not have a fire label, it is not fire-rated regardless of its construction. Fire labels must never be removed or painted over.

Frequently Asked Questions

CDF’s ProBuilder tool allows contractors, architects, and facility managers to configure fire-rated door and frame assemblies online. During configuration, ProBuilder displays compatible fire rating options based on your selected door type, frame type, and hardware. ProBuilder prevents incompatible combinations (such as selecting a 3-hour rating with a drywall frame) and provides instant pricing for the complete assembly.

To configure a fire-rated assembly, visit cdfdistributors.com and open ProBuilder. Select your door type, frame type, and required fire rating. ProBuilder will guide you through compatible hardware and accessory selections.

For assistance selecting the correct fire rating for your project, call (855) 769-9895 or email sales@cdfdoors.com. CDF’s sales team is available Monday through Friday, 7:30 AM to 4:30 PM CT.

Configure Your Assembly

The frame type determines the maximum fire rating available for the assembly. Frame and door ratings must match, and the frame type must support the required rating level.

Drywall frames (wrap-around frames for metal stud walls) can be fire-rated up to a maximum of 90 minutes. Any project requiring a rating above 90 minutes must use a masonry frame.

Masonry frames (welded frames set into block, concrete, or masonry walls) can be fire-rated up to a maximum of 180 minutes (3 hours). Masonry frames are required for all 3-hour-rated wall assemblies.

Frame Type Limitations

Metal doors (hollow metal construction) can be fire-rated for up to 180 minutes (3 hours). Metal doors are required for any application exceeding the 90-minute rating, as wood doors cannot achieve ratings above 90 minutes. Metal doors paired with masonry frames provide the highest available fire rating for commercial door assemblies.

Metal Door Fire Ratings

CDF offers two types of wood door construction for fire-rated applications. The construction type determines the maximum fire rating the door can achieve.

Standard wood doors with solid core construction (particleboard core with crossband and matching edge) are rated for 20 minutes. These doors are suitable for corridor applications in 1-hour-rated walls where only a 20-minute door rating is required.

Wood doors with mineral core construction (mineral core with mineral bonded crossband and matching edge) can be rated for 45, 60, or 90 minutes. The mineral core provides significantly greater fire resistance than particleboard. These doors are required for any wood door application above the 20-minute rating level.

The visual difference between the two constructions is internal. Both door types have the same exterior face finish and matching edges. The core material—particleboard versus mineral—determines the fire rating capacity.

Wood Door Construction and Fire Ratings

The following table summarizes the five standard fire rating levels for commercial door assemblies, including the door types, frame types, and maximum ratings for each material combination. Use this table to identify the correct assembly configuration for your project’s fire-resistance requirements.

Fire Rating Comparison

Commercial door assemblies are available in five standard fire rating levels: 20, 45, 60, 90, and 180 minutes. The required rating depends on the fire-resistance rating of the wall and the specific code requirements for the opening location. The following sections describe each rating level, its typical applications, and the door and frame types that support it.

20-Minute Fire Rating

A 20-minute fire rating is the lowest standard rating for commercial door assemblies. It is typically required for corridor doors in 1-hour-rated corridor walls and for doors in smoke partitions. Standard wood doors with solid core construction meet the 20-minute rating. Both drywall and masonry frames are available at this rating level.

45-Minute Fire Rating

A 45-minute fire rating is required for openings in 1-hour fire-resistance-rated walls, commonly found in corridor separations and room partitions in commercial buildings. Wood doors at this rating level require mineral core construction to achieve the higher fire resistance. Both drywall and masonry frames support the 45-minute rating.

60-Minute Fire Rating

A 60-minute fire rating is used for openings in 1-hour fire-resistance-rated walls where the AHJ or project specifications require the higher door rating. This is common in stairwell enclosures serving buildings of four stories or fewer. Wood doors require mineral core construction, and metal doors also support this rating. Both drywall and masonry frames are available.

90-Minute Fire Rating

A 90-minute fire rating is required for openings in 2-hour fire-resistance-rated walls, including stairwell enclosures in taller buildings and certain occupancy separations. This is the maximum fire rating available for drywall frames and wood doors. Wood doors at this level must have mineral core construction. Metal doors and masonry frames also support the 90-minute rating.

180-Minute (3-Hour) Fire Rating

A 180-minute fire rating (3 hours) is the highest standard rating for commercial door assemblies. It is required for openings in 3-hour or 4-hour fire-resistance-rated walls, such as occupancy separations between high-hazard areas and area separation walls. This rating level requires metal doors and masonry frames. Drywall frames and wood doors cannot achieve this rating.

Fire Rating Levels

The following rules apply to all fire-rated commercial door assemblies. These requirements are based on NFPA 80 (Standard for Fire Doors and Other Opening Protectives) and standard industry practice as applied by CDF Distributors.

Matching Labels on All Components

When a door is fire-rated, the frame must also be fire-rated to the same level. All components in the assembly—including lite kits (glass), louvers, and certain hardware—must carry matching fire labels. A fire-rated door installed in a non-rated frame, or with non-rated hardware, does not constitute a compliant fire-rated assembly.

Self-Closing and Self-Latching

All fire-rated doors must be self-closing and self-latching. This means every fire-rated assembly requires a door closer and a latching lockset. Passage-function hardware (non-latching) cannot be used on fire-rated doors. The door must close and latch automatically without manual intervention.

Fire Labels

All rated doors and frames must have a physical fire label. CDF rivets a metal fire label onto every fire-rated door and frame before shipping. If a door or frame does not have a fire label riveted to it, it is not fire-rated regardless of its construction. Fire labels must never be removed or painted over.

Undercut Limitations

Fire-rated doors cannot have an undercut (gap at the bottom of the door) greater than 3/4 inch. Larger undercuts compromise the fire resistance of the assembly and will fail inspection by the AHJ.

Storefronts and Hurricane-Rated Doors

Storefront doors and hurricane-rated doors cannot be fire-rated. These are separate product categories with different testing and certification requirements. If a project requires both wind resistance and fire resistance, consult with CDF’s sales team and the project’s design professional for alternative solutions.

General Rules for Fire-Rated Assemblies

State and local building codes, typically based on the International Building Code (IBC), specify where fire-rated door assemblies must be installed. The Authority Having Jurisdiction (AHJ) enforces these requirements during plan review and inspection. Fire-rated assemblies are commonly required in the following locations:

• Stairwell enclosures and exit passageways

• Corridor walls separating occupied spaces from means of egress

• Occupancy separation walls (e.g., between a retail space and a parking garage)

• Mechanical and electrical room enclosures

• Shaft enclosures (elevator shafts, duct shafts)

• Hazardous storage areas

The required fire rating of a door assembly is determined by the fire-resistance rating of the wall in which it is installed. Door assemblies are typically rated at 75% or less of the wall’s rating, as defined in NFPA 80 and the IBC.

When Fire Ratings Are Required

Fire ratings indicate the length of time a door, frame, and hardware assembly has been tested to resist the passage of fire and smoke. Commercial buildings require fire-rated door assemblies wherever building codes mandate compartmentalization of fire and smoke, including stairwells, corridors, mechanical rooms, and occupancy separations. The fire rating applies to the complete assembly—door, frame, and hardware must all carry matching fire labels to comply with code requirements.

CDF Distributors fabricates and ships fire-rated door and frame assemblies from its Nashville, Tennessee headquarters. You can configure fire-rated assemblies online using CDF’s ProBuilder tool at cdfdistributors.com. For assistance selecting the correct fire rating for your project, call (855) 769-9895 or email sales@cdfdoors.com.