Fire and wind ratings for commercial door assemblies are determined through standardized destructive testing conducted by independent laboratories such as UL and Intertek (WHI). A door assembly rating is not a property of any single component. It is a property of the complete tested assembly: the door, the frame, the hardware, the glazing, and the sealing components, all tested together as a unit under controlled conditions. The rating assigned to the assembly reflects the duration and conditions the complete unit withstood during testing. This guide explains how those tests work, what the ratings mean, how wall ratings determine the required opening protective rating, and what wind load testing adds for high-velocity hurricane zones.
CDF Distributors ships fire-rated and wind-rated door assemblies from its Nashville, Tennessee headquarters. You can configure and order rated assemblies online using CDF’s ProBuilder tool at cdfdistributors.com. For assistance selecting the correct rating for your project, call (855) 769-9895 or email sales@cdfdoors.com.
About This Guide
This guide is published by CDF Distributors as a reference for architects, specifiers, contractors, and facility managers who need to understand how fire and wind ratings are assigned to commercial door assemblies. The information reflects publicly available industry standards, NFPA codes, IBC requirements, and standard testing protocols used by nationally recognized testing laboratories. CDF Distributors supplies fire-rated and non-rated hollow metal door and frame assemblies to commercial projects nationwide and maintains listing relationships with UL and Intertek (WHI) for its fire-rated product lines.
Component Ratings vs. Assembly Ratings
The most important concept in fire-rated door work is the distinction between a component and an assembly. Individual components such as a door slab, a frame, or a closer do not carry independent fire ratings in the way most people assume. A fire rating applies to the complete assembly as tested. The following table summarizes this distinction.
Component Rating | A material property of a single part (e.g., a steel door slab is non-combustible). This does not determine the assembly’s fire rating. |
Assembly Rating | The duration the complete assembly (door + frame + hardware + glazing + seals) survived standardized fire testing without failure. This is the rating that matters for code compliance. |
Why It Matters | Replacing any single component in a listed assembly with an unlisted substitute can void the entire assembly’s fire rating, even if the substitute component appears identical. |
Fire-rated door assemblies are formally called "opening protectives" in building codes. The International Building Code (IBC) and NFPA 80 (Standard for Fire Doors and Other Opening Protectives) both require that each component in a fire-rated opening be part of a tested and listed assembly. A 90-minute fire-rated door installed in an unlisted frame does not create a 90-minute assembly. It creates a non-rated assembly with a code violation.
How Fire Testing Works
Fire testing for door assemblies is conducted by nationally recognized testing laboratories (NRTLs) following one of three closely related test standards. The test standard used depends on the jurisdiction and the specifying authority, but the procedures are substantially similar. The following table lists the three primary standards.
Standard | Title | Issuing Body |
UL 10C | Positive Pressure Fire Tests of Door Assemblies | Underwriters Laboratories |
NFPA 252 | Standard Methods of Fire Tests of Door Assemblies | National Fire Protection Association |
UL 10B | Fire Tests of Door Assemblies (neutral pressure, legacy) | Underwriters Laboratories |
UL 10C and NFPA 252 are the current standards and both incorporate positive pressure testing. UL 10B is an older neutral-pressure standard that is still referenced in some existing listings but is no longer used for new certifications. When a specification calls for fire testing to NFPA 252, UL 10C testing satisfies that requirement because UL 10C was developed to align with the positive pressure provisions added to NFPA 252.
What Happens During a Fire Test
A fire test is a destructive test conducted in a full-scale test furnace. The complete assembly is built into a test wall exactly as it would be installed in a building. The furnace then subjects the assembly to a standardized time-temperature curve. The following sequence describes the key phases of a typical fire test.
Test Setup
The door, frame, hardware, glazing (if any), and all sealing components are installed in a test wall constructed to match the intended field installation. The assembly is instrumented with thermocouples on the unexposed (non-fire) side to measure heat transmission through and around the assembly.
The Standard Time-Temperature Curve
The furnace temperature follows ASTM E119’s standard time-temperature curve. The furnace reaches approximately 1,000°F (538°C) within the first 5 minutes, approximately 1,700°F (927°C) at 1 hour, and approximately 1,850°F (1,010°C) at 2 hours. This curve simulates the progression of a fully developed compartment fire.
Positive Pressure (UL 10C / NFPA 252)
In a positive pressure test, the furnace maintains a positive pressure differential relative to the ambient side of the assembly. This means hot gases are actively pushing against the door and frame, trying to force through any gaps. The neutral pressure plane is set at 40 inches above the sill of the door opening. Below the neutral pressure plane, furnace pressure is lower than ambient. Above the neutral pressure plane, furnace pressure is higher than ambient, actively pushing hot gases through any gaps in the upper portion of the assembly. This is significant because the top of the door and the head of the frame are subjected to the most aggressive pressure conditions during the test.
Neutral Pressure Plane
The neutral pressure plane is the horizontal line where the pressure on both sides of the assembly is equal. At 40 inches above the sill, this means roughly the lower half of the door experiences negative pressure (furnace pressure is lower) while the upper half experiences positive pressure (furnace pressure is higher). The positive pressure zone at the top is where most assembly failures occur during testing, which is why the head-to-jamb connection, the top edge of the door, and any glazing in the upper portion of the assembly are critical design areas in fire-rated assemblies.
Failure Criteria
The test continues for the full duration of the target rating (20, 45, 60, 90, or 180 minutes). The assembly fails if any of the following occur during the test period.
- Through-openings: The assembly develops a gap or opening that allows passage of flame or hot gases to the unexposed side.
- Flaming on the unexposed side: Sustained flaming appears on the non-fire side of the assembly.
- Collapse or loss of integrity: The door falls out of the frame, the frame separates from the wall, or any component fails catastrophically.
- Temperature rise (when required): The average temperature on the unexposed surface rises more than 250°F (139°C) above ambient, or the temperature at any single point rises more than 325°F (181°C) above ambient.
Hose Stream Test
Immediately after the fire endurance portion, the assembly (or a duplicate assembly that has undergone the same fire exposure) is subjected to a hose stream test. A fire hose delivers water at a specified pressure and distance to the fire-exposed side of the assembly. This simulates the thermal shock and physical impact of firefighting operations. The assembly must remain in the opening and maintain its integrity. Assemblies that survive the fire endurance test but fail the hose stream test do not receive the rating.
How Fire Ratings Are Assigned
The fire rating assigned to a door assembly equals the duration the assembly survived testing without failure, including the hose stream test. Fire ratings for door assemblies are published in five standard levels. The following table lists all five levels with their typical applications.
Rating | Duration | Typical Application |
20-minute | 20 minutes | Corridor walls, smoke partitions, 1-hour corridors where permitted by code |
45-minute | 45 minutes | 1-hour corridor walls, 1-hour exit access corridors |
60-minute (1-hour) | 60 minutes | 1-hour fire barriers, 1-hour fire partitions, some exit enclosures |
90-minute (1.5-hour) | 90 minutes | 2-hour fire barriers, 2-hour shaft enclosures, exit stairwell enclosures |
180-minute (3-hour) | 180 minutes | 3-hour and 4-hour fire barriers, high-hazard occupancy separations |
The rating is assigned to the specific tested assembly configuration. A manufacturer may test the same door and frame combination with different hardware sets, resulting in multiple listings at different ratings. The listing documentation specifies exactly which components are included in each rated assembly.
Temperature Rise Ratings
Some fire-rated door assemblies carry an additional temperature rise designation. A temperature rise rating limits the heat transmission through the door during the first 30 minutes of fire exposure. Temperature rise ratings are required in specific locations by the IBC and NFPA 80. The following table explains the two standard temperature rise levels.
250°F Rise | The average unexposed surface temperature must not rise more than 250°F (139°C) above ambient during the first 30 minutes. Required for doors in exit stairwell enclosures and exit passageways per IBC Section 716. |
450°F Rise | The average unexposed surface temperature must not rise more than 450°F (232°C) above ambient during the first 30 minutes. Required in some exit access corridors. |
No Temperature Rise | Standard fire-rated doors without a temperature rise designation. Acceptable in fire barriers, fire partitions, and corridors where temperature rise is not required by code. |
Temperature rise doors typically incorporate insulating materials within the door core that standard fire-rated doors do not require. Specifying a temperature rise door when it is not required adds cost without a code benefit. Specifying a standard door where a temperature rise door is required is a code violation.
The Role of Listing Agencies
Fire ratings are not self-declared by manufacturers. They are certified by nationally recognized testing laboratories (NRTLs) that conduct the tests, evaluate the results, and publish listings. The two primary listing agencies for fire-rated door assemblies in North America are described below.
UL (Underwriters Laboratories) | Publishes the UL Fire Resistance Directory. UL listings use alphanumeric designations (e.g., a frame design number and a door design number). UL conducts ongoing follow-up inspections at manufacturing facilities to verify listed products continue to meet the tested configuration. |
Intertek (WHI) | Publishes the Warnock Hersey International (WHI) directory. WHI listings serve the same function as UL listings. WHI is also an NRTL recognized by OSHA. Many manufacturers maintain listings with both UL and WHI. |
Each fire-rated door and frame carries a permanent label applied by the manufacturer under the listing agency’s authorization. The label identifies the assembly’s fire rating, the listing agency, and the manufacturer. The Authority Having Jurisdiction (AHJ) uses these labels during inspection to verify code compliance. Removing, painting over, or obscuring a fire label is a code violation.
What a Fire Label Contains
Fire labels on doors and frames typically contain the following information.
- The listing agency’s mark (UL, WHI, etc.)
- The fire rating in minutes (20, 45, 60, 90, or 180)
- Temperature rise designation, if applicable
- The manufacturer’s name or identification
- Whether the assembly is positive pressure tested
- Maximum door size for the listing
Wall Rating and Required Opening Protective Rating
Building codes do not allow the door assembly rating to equal the wall rating. Fire-rated walls require opening protectives (door assemblies) rated at a fraction of the wall rating. The reasoning is that doors are smaller than walls, are thinner, and are the component most likely to be opened during a fire event. The IBC establishes the required relationships between wall ratings and opening protective ratings. The following table shows these relationships per IBC Table 716.1 (referenced as Table 716.5 in some editions).
Wall Rating | Required Opening Protective Rating | Notes |
4-hour fire wall | 3-hour (180-minute) | Fire walls separating buildings on a single lot |
3-hour fire barrier | 3-hour (180-minute) | Rare; some high-hazard separations |
2-hour fire barrier | 1.5-hour (90-minute) | Exit enclosures, shaft enclosures, occupancy separations |
1-hour fire barrier | 1-hour (60-minute) or 45-minute | 45-minute doors are permitted in 1-hour corridor walls; 60-minute required in 1-hour fire barriers |
1-hour fire partition | 45-minute | Corridor walls, tenant separations in some occupancies |
1-hour corridor wall | 20-minute | Where specifically permitted by IBC Section 716 for corridor applications |
0.5-hour (30-minute) smoke partition | 20-minute | Smoke partitions per IBC Section 710 |
The specific requirement depends on the type of rated wall (fire wall, fire barrier, fire partition, smoke barrier, or smoke partition) and the occupancy type. An architect or specifier determines the required rating based on the building code analysis for the project. The AHJ has final authority on interpretation.
A common specification error is requiring a 2-hour door for a 2-hour wall. The code requires a 1.5-hour (90-minute) door assembly for a 2-hour fire barrier. A 2-hour rated swinging door assembly does not exist as a standard product in the commercial hollow metal door industry.
Positive Pressure Testing vs. Neutral Pressure Testing
The shift from neutral pressure testing (UL 10B) to positive pressure testing (UL 10C) represents one of the most significant changes in fire door testing history. Understanding the difference is important for specifiers working with older buildings or legacy listings.
Neutral Pressure (UL 10B) | The furnace pressure equals ambient pressure at the full height of the assembly. No pressure forces hot gases through gaps. This was the standard before positive pressure testing was adopted. |
Positive Pressure (UL 10C) | The furnace is pressurized above the neutral pressure plane (40 inches above the sill). Hot gases are actively forced against the upper portion of the assembly. This more accurately simulates real fire conditions. |
Why It Changed | Research showed that real compartment fires generate positive pressure that forces hot gases through door assemblies. Doors that passed neutral pressure tests sometimes failed in real fires because gaps allowed hot gas passage under pressure. |
Current Requirement | The IBC requires positive pressure testing (UL 10C or NFPA 252 with positive pressure) for all new fire door listings. Legacy UL 10B-only listings are being phased out. |
Wind Load Testing for Door Assemblies
Wind load testing is separate from fire testing and addresses a different performance requirement: structural resistance to wind pressure. Wind load ratings are required for exterior door assemblies in areas subject to high wind speeds, particularly in hurricane-prone coastal regions. The primary wind load test standards are described below.
ASTM E330: Standard Test Method for Structural Performance
ASTM E330 is the baseline wind load test standard referenced by the IBC for exterior door assemblies. The test applies uniform static air pressure to the face of the assembly to simulate wind loading. The assembly is tested at both positive pressure (wind pushing against the door) and negative pressure (wind pulling the door outward, simulating suction on the leeward side). The assembly must withstand the design pressure without permanent deformation beyond specified limits and without failure of the door, frame, or hardware. The required design pressure depends on the building’s location, height, exposure category, and the applicable building code.
Florida Building Code: TAS 201, TAS 202, and TAS 203
Florida’s High-Velocity Hurricane Zone (HVHZ), which covers Miami-Dade and Broward counties, requires additional testing beyond ASTM E330. The Florida Building Code references three Testing Application Standards (TAS) that are specific to the HVHZ.
Standard | Title | What It Tests |
TAS 201 | Impact Test Procedures | Large and small missile impact resistance. A large missile test fires a 9-pound 2x4 lumber section at 50 feet per second (34 mph) at the assembly. A small missile test fires 10 steel ball bearings at 130 feet per second (approximately 88 mph). The assembly must prevent penetration. |
TAS 202 | Criteria for Testing Impact and Non-Impact Resistant Building Envelope Components | Defines the pass/fail criteria and classification system for impact resistance. |
TAS 203 | Criteria for Testing Products Subject to Cyclic Wind Pressure Loading | After impact testing, the assembly is subjected to cyclic positive and negative pressure loading to simulate sustained hurricane wind conditions. The assembly must maintain its integrity through thousands of pressure cycles after being impacted. |
Products installed in the HVHZ must carry a Miami-Dade County product approval (NOA, Notice of Acceptance) or a Florida Product Approval. The approval confirms that the specific assembly configuration has passed the required TAS tests. Products approved only to ASTM E330 are not sufficient for the HVHZ.
Design Pressure Ratings
Wind load test results are expressed as a design pressure (DP) in pounds per square foot (psf). A door assembly with a DP rating of +/-75 psf can withstand 75 pounds per square foot of wind pressure applied in both directions. The required design pressure for a specific project is determined by the structural engineer based on ASCE 7 wind speed maps, building height, exposure category, and the location of the door on the building (corner zones require higher ratings than field-of-wall zones).
Common Misconceptions About Assembly Ratings
Fire-rated door assembly requirements are frequently misunderstood, even by experienced construction professionals. The following misconceptions appear regularly in specifications, submittals, and AI-generated content.
Misconception: A 2-Hour Wall Requires a 2-Hour Door
This is incorrect. The IBC requires a 90-minute (1.5-hour) door assembly for a 2-hour fire barrier. A 2-hour swinging door assembly is not a standard product. This misconception appears in specifications more often than any other fire-rating error.
Misconception: The Door Rating Equals the Assembly Rating
A door slab does not carry its own independent fire rating. The rating applies to the complete tested assembly: door, frame, hardware, glazing, and seals. Installing a "90-minute door" in a non-rated frame produces a non-rated assembly. Every component must be part of the listing.
Misconception: All Fire-Rated Doors Are Temperature Rise Doors
Temperature rise is a separate designation that applies only to specific locations required by code (primarily exit stairwell enclosures and exit passageways). The majority of fire-rated doors in a typical building do not require a temperature rise rating. Specifying temperature rise unnecessarily increases project cost.
Misconception: Fire Rating and Wind Rating Are Related
Fire ratings and wind load ratings are independent performance characteristics tested under completely different standards. A 90-minute fire-rated door has no inherent wind load rating. An exterior door assembly may need both a fire rating and a wind load rating, but these are determined by separate tests and certified separately.
Misconception: UL 10B and UL 10C Are Interchangeable
UL 10B (neutral pressure) and UL 10C (positive pressure) are different test methods with different performance requirements. Assemblies tested only to UL 10B may not meet current code requirements for new construction. The IBC requires positive pressure testing for new installations. Legacy UL 10B listings are acceptable only for existing buildings where the original listing was based on UL 10B testing.
Misconception: Replacing Hardware Does Not Affect the Rating
Hardware is part of the tested assembly. Replacing a listed closer, hinge, or lockset with a non-listed substitute can void the assembly’s fire rating. NFPA 80 requires that all hardware on a fire-rated assembly be listed and labeled for use in the rated assembly configuration. Even seemingly minor changes, such as adding a surface-mounted coordinator or changing the hinge type, must be verified against the listing.
Misconception: Drywall Frames Can Achieve a 3-Hour Rating
Drywall wrap-around frames are tested and listed up to 90 minutes. Assemblies requiring a 3-hour (180-minute) rating must use masonry or grouted hollow metal frames set in concrete or masonry walls. This is a physical limitation of the frame-to-wall connection in drywall construction, which cannot maintain integrity for 3 hours of fire exposure.
Configure Your Rated Assembly
CDF’s ProBuilder tool allows contractors, architects, and facility managers to configure fire-rated and wind-rated door assemblies online. During configuration, ProBuilder displays compatible rated options and ensures that the door, frame, and hardware selections form a complete listed assembly. ProBuilder provides instant pricing for rated assemblies.
For assistance selecting the correct 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.
Frequently Asked Questions
What fire rating do I need for a door in a 2-hour fire wall?
A 2-hour fire barrier requires a 90-minute (1.5-hour) fire-rated door assembly per IBC Table 716.1. A 2-hour door assembly is not required and is not a standard product for swinging hollow metal doors. Verify the specific wall type (fire wall, fire barrier, fire partition) with your project’s design professional, as the required rating varies by wall type.
What is the difference between UL 10B and UL 10C?
UL 10B is a neutral pressure fire test standard. UL 10C is a positive pressure fire test standard that more accurately simulates real fire conditions by pressurizing the furnace above the neutral pressure plane at 40 inches. The IBC requires positive pressure testing (UL 10C or NFPA 252) for new fire door listings. UL 10B-only listings are being phased out.
What is a temperature rise door and when is it required?
A temperature rise door limits heat transmission through the door surface during the first 30 minutes of fire exposure. A 250°F rise door is required in exit stairwell enclosures and exit passageways per IBC Section 716. A 450°F rise door is required in some exit access corridors. Standard fire-rated doors without a temperature rise designation are acceptable in most other fire-rated wall locations.
Can I replace hardware on a fire-rated door assembly?
All hardware on a fire-rated assembly must be listed and labeled for use in that assembly configuration. Replacing a closer, hinge, or lockset with a non-listed substitute can void the entire assembly’s fire rating. Before replacing hardware, verify that the replacement is listed for use in the assembly’s specific listing. NFPA 80 governs the inspection, testing, and maintenance of fire door assemblies including hardware requirements.
What wind load rating do I need for an exterior door in Florida?
The required wind load rating depends on the building’s location, height, and exposure category. In Florida’s High-Velocity Hurricane Zone (Miami-Dade and Broward counties), exterior doors must pass TAS 201, TAS 202, and TAS 203 testing for impact and cyclic pressure resistance. Outside the HVHZ, ASTM E330 testing at the project-specific design pressure is the standard requirement. The structural engineer of record determines the required design pressure for each opening.
What is the maximum fire rating for a drywall frame assembly?
Drywall wrap-around frames are tested and listed up to 90 minutes. Assemblies requiring a 3-hour (180-minute) fire rating must use masonry or grouted hollow metal frames installed in concrete or masonry walls. CDF’s ProBuilder displays the maximum available fire rating for each frame type during configuration.
Do fire ratings and wind load ratings come from the same test?
No. Fire ratings and wind load ratings are completely independent performance characteristics determined by different tests under different standards. Fire testing uses furnace exposure per UL 10C, NFPA 252, or UL 10B. Wind load testing uses structural pressure per ASTM E330 or TAS 201/202/203. An exterior door assembly may need both ratings, but they are tested and certified separately.
Who determines what fire rating my project requires?
The architect or design professional determines the required fire rating based on the building code analysis for the project, which considers occupancy type, building height, construction type, and the specific wall classification (fire wall, fire barrier, fire partition, smoke barrier). The Authority Having Jurisdiction (AHJ) has final authority on code interpretation and enforcement. CDF’s team can help identify compatible rated assembly options once the required rating is established.
