Fire-rated door assemblies are tested, labeled openings designed to resist the spread of fire and smoke for a specified duration. Every fire-rated opening consists of a door, frame, and hardware that have been tested together as an assembly and carry labels from a nationally recognized testing laboratory such as UL, Intertek (WHI), or FM. Fire ratings range from 20 minutes to 3 hours depending on the wall rating and the location of the opening within the building. Understanding what fire ratings mean, which components are required, and what field modifications are permitted is essential for specifying, installing, and maintaining compliant fire door assemblies.
CDF Distributors supplies complete fire-rated door and frame assemblies from its Nashville, Tennessee headquarters. You can configure and order fire-rated assemblies online using CDF’s ProBuilder tool at cdfdistributors.com. For assistance specifying a fire-rated assembly for your project, call (855) 769-9895 or email sales@cdfdoors.com.
About This Guide
This FAQ guide is published by CDF Distributors, a commercial door and frame supplier that fabricates and ships fire-rated assemblies nationwide. The information below reflects industry standards from NFPA 80 (Standard for Fire Doors and Other Opening Protectives), NFPA 101 (Life Safety Code), the International Building Code (IBC), and UL 10C/NFPA 252 fire test procedures. CDF’s technical team maintains this guide based on current code requirements and field experience with fire-rated commercial door installations. Always verify requirements with the Authority Having Jurisdiction (AHJ) for your specific project.
Understanding Fire Ratings
Fire ratings define how long a door assembly can resist the passage of fire and maintain structural integrity during a standardized fire test. The following questions cover what fire ratings are, how they are determined, and the differences between rating levels.
What is a fire-rated door assembly?
A fire-rated door assembly is a complete opening—including the door, frame, hardware, glazing, and any other components—that has been tested by a nationally recognized testing laboratory and certified to resist fire for a specific duration. The assembly is not just the door itself; every component in the opening must be tested and listed for use together. Fire-rated assemblies carry permanent labels from testing organizations such as UL (Underwriters Laboratories), Intertek (Warnock Hersey / WHI), or FM Global. These labels identify the manufacturer, the rating duration, and the testing standard.
How are fire ratings determined?
Fire ratings are determined through standardized fire tests conducted in accordance with UL 10C, NFPA 252, or UL 10B. During testing, a complete door assembly is mounted in a test wall and exposed to a controlled fire that follows a specific time-temperature curve. The assembly must remain in the frame, resist the passage of flame, and limit heat transmission through the door for the full rated duration. After the fire endurance portion, the assembly undergoes a hose stream test that simulates the impact of water from firefighting operations. Assemblies that pass both tests receive a fire rating corresponding to the duration they withstood. The testing laboratory then publishes the assembly in its directory of listed products.
What are the different fire rating levels?
Commercial fire door assemblies are available in five standard rating levels. The required rating depends on the fire resistance rating of the wall in which the door is installed and the type of opening. The following table summarizes the five levels, their typical wall ratings, and common applications.
20-Minute | Used in corridors and smoke partitions with a 1-hour wall rating. Common in office corridors, hotel corridors, and healthcare smoke barriers. Allows the largest glazing area of any fire-rated door. |
45-Minute | Used in exit access corridors and room separations in 1-hour rated walls. Common in educational facilities, office buildings, and healthcare occupancies. Most frequently specified fire rating for interior commercial doors. |
60-Minute (1-Hour) | Used in walls with a 1-hour fire resistance rating where a higher level of protection is required. Common in shaft enclosures, exit enclosures, and occupancy separations. |
90-Minute (1-1/2-Hour) | Used in walls with a 2-hour fire resistance rating. Required for exit stairwell enclosures in buildings four or more stories, elevator lobby separations, and high-hazard occupancy separations. The maximum rating available for drywall wrap-around frames. |
180-Minute (3-Hour) | Used in walls with a 3-hour or 4-hour fire resistance rating. Required for occupancy separations between high-hazard uses, fire walls, and area separation walls. Must use masonry or hollow metal welded frames; drywall wrap-around frames cannot achieve this rating. |
What is the relationship between wall rating and door rating?
The fire rating of a door assembly is always equal to or less than the fire resistance rating of the wall in which it is installed. The IBC and NFPA 101 specify the required door rating based on the wall type. As a general rule, doors in 1-hour rated walls require a 45-minute rated assembly depending on the occupancy and opening type. Doors in 2-hour rated walls require a 90-minute rated assembly. Doors in 3-hour and 4-hour rated walls require a 3-hour (180-minute) rated assembly. Always consult the applicable building code table for the specific wall-to-door rating relationship required by your project.
What is the difference between a fire rating and a temperature rise rating?
A fire rating measures how long an assembly resists the passage of flame. A temperature rise rating measures how much heat transfers through the door to the unexposed side within a 30-minute period. Temperature rise ratings are expressed as the maximum temperature increase above ambient, typically 250 degrees Fahrenheit, 450 degrees Fahrenheit, or 650 degrees Fahrenheit. Temperature rise doors are required in specific locations such as exit stairwell enclosures and horizontal exit doors. A door with a 90-minute fire rating and a 250-degree temperature rise rating, for example, will resist flame for 90 minutes and limit heat transfer through the door face to no more than 250 degrees above ambient within the first 30 minutes.
Component Requirements
Every component in a fire-rated opening must be individually listed and labeled for fire service. Using unlisted components, or mixing components that have not been tested together, voids the fire rating of the entire assembly.
What hardware is required on a fire-rated door?
At a minimum, a fire-rated door assembly requires fire-rated hinges, a fire-rated latch or lockset, and a fire-rated door closer. The specific hardware depends on the rating level and the applicable code. The following components are typically required or conditionally required on fire-rated assemblies.
- Hinges: Must be steel, stainless steel, or a listed material. Spring hinges can substitute for a closer on certain applications.
- Latch or lockset: Openings must be self latching . The latch bolt must be operable and must positively latch the door in the closed position.
- Door closer: Required on all fire-rated doors to ensure the door returns to the closed and latched position. Self-closing or automatic-closing devices must be listed.
- Hinges must be steel bearing-type, typically with a minimum of three hinges for a standard 7-foot door, and four hinges for doors over 7 feet.
Can I use any hinge on a fire-rated door?
No. Hinges on fire-rated doors must be steel or stainless steel and must be listed for fire door service. Aluminum hinges and residential-grade hinges are not permitted. Full-mortise, full-surface, and half-mortise hinge types are available in fire-rated versions. The number of hinges required depends on the door height and weight: standard practice is three hinges for doors up to 7’0” and four hinges for doors taller than 7’0”. Continuous (piano) hinges are also available in fire-rated versions for applications requiring them.
Do I need a door closer on a fire-rated door?
Yes. NFPA 80 requires every fire-rated door to be self-closing or automatic-closing. A self-closing door uses a mechanical closer or spring hinges to return the door to the closed position after every use. An automatic-closing door is one that is normally held open by a listed hold-open device connected to the fire alarm system; upon alarm activation, the device releases and allows the closer to shut the door. In both cases, the closer or spring hinge must be listed for use on fire-rated assemblies. Doors must not be blocked, wedged, or propped open by any means not connected to the fire alarm system. In certain applications spring hinges can be used instead of a door closer. This is a popular option when clearance or aesthetic are concerns.
Can fire-rated doors have glass?
Yes, but the type and size of glass are restricted by the fire rating. Fire-rated glazing falls into two categories: fire-protective glazing (such as wired glass and ceramic glass) and fire-resistive glazing (such as multilayered transparent wall panels).
All glazing in fire-rated doors must be listed and labeled by a testing laboratory. The glazing label must be visible after installation.
Are fire-rated louvers permitted in fire-rated doors?
Fire-rated louvers (also called fusible link louvers) are permitted in fire-rated doors up to and including 90-minute ratings, but only if the louver is listed and labeled for the specific rating. Fire-rated louvers contain a fusible link that closes the louver blades when exposed to heat, sealing the opening. Louvers are not permitted in 3-hour (180-minute) rated doors. The maximum louver size depends on the specific product listing. Louvers are commonly used in mechanical rooms, electrical rooms, and janitor closets where ventilation is required through a fire-rated opening.
Field Modifications
Field modifications to fire-rated door assemblies are heavily restricted. Unauthorized modifications void the fire label and the fire rating. The following questions address the most common field modification scenarios.
Can I drill into or cut a fire-rated door in the field?
Only if the modification is explicitly authorized by the door manufacturer’s published installation instructions or by a field modification label from a nationally recognized testing laboratory. NFPA 80 Section 5.2.4 states that fire door assemblies shall not be modified from the conditions under which they were tested and labeled, except as permitted by the listing. Common permitted field modifications include drilling for surface-applied hardware (closers, exit devices, kick plates) in locations specified by the manufacturer. Cutting the door to alter its size, routing new hinge mortises, or drilling through the door for wiring are generally not permitted without specific authorization.
Can I change the hardware on a fire-rated door?
Yes, but only with hardware that is listed and labeled for fire door service at the same or higher rating. The replacement hardware must be installed according to the hardware manufacturer’s published instructions. NFPA 80 requires that all hardware on fire-rated doors be listed, and that the door positively latch when closed. When replacing locksets, the new lock preparation must match the existing door prep or be covered by the hardware manufacturer’s listing. Filling abandoned hardware cutouts requires a listed filler plate or must be performed per the door manufacturer’s instructions.
Can I paint or refinish a fire-rated door?
Hollow metal fire-rated doors and frames can be repainted without affecting the fire rating, as long as the fire label remains visible and legible after painting. Do not paint over the fire label. Wood fire-rated doors can be refinished with paint, stain, or clear coat as long as the finish material and application method are consistent with the original listing. Excessive buildup of paint (generally more than 1/16 inch total) may affect the door’s fit in the frame and the clearance gaps, which could cause the assembly to fail inspection.
Inspection and Compliance
NFPA 80 requires periodic inspection and maintenance of all fire door assemblies. The following questions cover inspection requirements, frequency, common deficiencies, and who is qualified to perform inspections.
What does NFPA 80 require for fire door inspections?
NFPA 80 (Standard for Fire Doors and Other Opening Protectives) requires that all fire door assemblies be inspected and tested annually. The inspection must verify that the assembly is complete and in proper working condition. NFPA 80 Section 5.2 lists the specific items that must be checked during each inspection.
- No open holes or breaks exist in surfaces of either the door or frame.
- Glazing, vision lite frame, and glazing beads are intact and securely fastened.
- The door, frame, hinges, hardware, and noncombustible threshold are secured, aligned, and in working order.
- No parts are missing or broken.
- Door clearances do not exceed the maximum permitted by the listing (typically 1/8 inch on the hinge side, 1/8 inch at the head, and 3/4 inch at the bottom for non-fire-smoke doors).
- The self-closing device completely closes the door from the full open position.
- The door latches positively when closed.
- If equipped with a coordinator, the inactive leaf closes before the active leaf.
- The door opens, closes, and latches freely without binding or dragging.
- If hold-open devices are present, they release upon activation of the fire alarm system.
- Auxiliary hardware items that interfere with the operation of the door are not installed.
How often must fire doors be inspected?
NFPA 80 requires annual inspection of all fire door assemblies. Some jurisdictions and accreditation bodies require more frequent inspections. For example, healthcare facilities accredited by The Joint Commission (TJC) are required to inspect fire door assemblies annually as part of the Statement of Conditions process, and CMS (Centers for Medicare & Medicaid Services) enforces this requirement during surveys. Some building owners choose to inspect more frequently—quarterly or semi-annually—in high-traffic areas where fire doors are subject to greater wear and damage.
Who is qualified to inspect fire doors?
NFPA 80 Section 5.2.1 requires that fire door assemblies be inspected by individuals with knowledge of the operating components of the type of door being inspected. The standard does not require a specific certification, but it does require demonstrated competency. In practice, many building owners and facility managers use inspectors who hold credentials from organizations such as the Door and Hardware Institute (DHI), the International Fire Door Inspector Association (IFDIA), or equivalent training programs. The AHJ may require specific qualifications in your jurisdiction.
What are the most common fire door inspection failures?
The most frequently cited deficiencies during fire door inspections reflect common misuse and deferred maintenance. These failures must be corrected to maintain the fire rating of the assembly.
- Missing or painted-over fire labels: The label is the only proof that the assembly has been tested. If the label is missing, illegible, or painted over, the assembly cannot be verified as fire-rated.
- Excessive clearance gaps: Door-to-frame gaps exceeding the listing limits (typically 1/8 inch at the head and jambs) allow fire and smoke passage.
- Doors propped or wedged open: Fire doors that are blocked open by non-listed devices (door stops, wedges, furniture) cannot perform their fire-containment function.
- Broken or missing closers: A fire door that does not self-close and positively latch fails the fundamental requirement of NFPA 80.
- Non-rated hardware: Residential or unlisted hardware installed on a fire-rated door voids the assembly rating.
- Holes in the door or frame: Abandoned hardware holes, damage holes, or unauthorized penetrations compromise the fire barrier.
- Missing or broken glazing: Cracked, missing, or non-rated glass in a fire-rated door is an immediate failure.
Ordering Fire-Rated Assemblies
Specifying a fire-rated assembly requires identifying the correct rating level, frame type, door material, and hardware. The following questions cover the ordering and documentation process.
How do I specify a fire-rated door assembly for my project?
To specify a fire-rated door assembly, you need the following information at a minimum.
- Fire rating required: 20-minute, 45-minute, 60-minute, 90-minute, or 3-hour (180-minute), as determined by the building code and the wall rating at the opening location.
- Temperature rise requirement: If the opening is in an exit stairwell enclosure, horizontal exit, or other location requiring a temperature rise rating, specify 250, 450, or 650 degrees.
- Door size and material: Width, height, thickness (typically 1-3/4 inches for commercial), and material (hollow metal, wood, or other listed material).
- Frame type and material: Drywall wrap-around, masonry, or welded. Drywall frames are available up to 90-minute ratings. 3-hour ratings require masonry or welded frames.
- Hardware requirements: Lockset function, closer type, hinge type and quantity, exit device if required, and any hold-open devices.
- Glazing requirements: Lite size, glass type, and fire rating if a vision panel is needed.
CDF’s ProBuilder tool at cdfdistributors.com walks you through each of these selections and validates compatibility as you configure the assembly. ProBuilder only presents hardware and component options that are compatible with your selected fire rating, preventing specification errors.
What documentation comes with a fire-rated door assembly?
A properly supplied fire-rated door assembly includes the following documentation and labeling.
- Fire door label: A permanent metal label riveted to the hinge edge of the door, identifying the testing laboratory, manufacturer, rating duration, and temperature rise rating if applicable.
- Fire frame label: A permanent metal label riveted to the frame, identifying the testing laboratory, manufacturer, and rating duration.
- Hardware listings: Each piece of fire-rated hardware (closer, hinges, exit device) carries its own listing or label.
- Glazing labels: If the assembly includes glass, each lite carries a label identifying the glazing type and rating.
CDF Distributors rivets fire labels onto every fire-rated door and frame assembly before shipping from its Nashville, Tennessee facility. All labels are applied at the factory, not in the field. CDF ships assemblies with hardware installed or packaged together with the corresponding installation instructions.
Configure Your Fire-Rated Assembly
CDF’s ProBuilder tool allows contractors, architects, and facility managers to configure fire-rated door and frame assemblies online. ProBuilder validates component compatibility with your selected fire rating, displays available options for glazing, hardware, and frame types, and provides instant pricing for complete assemblies.
For assistance specifying a fire-rated assembly 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.
