Fire-Rated Doors: Here's What You Need to Know

If you're replacing a door in your home or managing a commercial property, you've probably come across the term fire-rated doors. But what exactly are they, where are they required in Canada and Ontario specifically, and how do you know if yours are up to code?

You're in the right place. Here's everything you need to know about fire-rated doors.

Key Takeaways: Fire-Rated Doors

• In Canada, fire‑rated doors are tested to national standards (such as CAN/ULC‑S104) and must carry an approved certification label (for example, ULC).
• A fire rating (20, 45, 60, 90 minutes, etc.) tells you how long the door assembly resists fire in a standardized lab test.
• The rating applies to the complete assembly, including the door, frame, hardware, seals, and any glass, not just the door slab.
• Modifying the door or hardware beyond the manufacturer’s instructions can void the rating and cause compliance issues. Always check before cutting, trimming, or swapping parts.
• Building and fire codes (NBCC, provincial building codes like the OBC, and fire codes like the OFC) dictate where fire‑rated doors are required; the exact requirements depend on building use, size, and layout.

What Are Fire-Rated Doors?

Fire-rated doors, also called fire doors, are door assemblies that have been laboratory-tested to resist and slow the spread of fire, smoke, and heat for a specified period. That period is the fire rating. Fire doors in Canada are rated as follows:

• 20 minutes -> basic fire control (common in condos)
• 45-60 minutes -> moderate protection (common in commercial and some residential buildings)
• 90 minutes+ -> high-risk areas (stairs, mechanical rooms, attached garages)

A 20-minute rating means the door held up for at least 20 minutes under controlled fire exposure conditions. A 90-minute rating means it held up for 90 minutes. Simple as that. Fire door ratings are based on the rating of the wall they’re installed in. The door rating is usually lower than the wall rating.

The fire rating doesn't apply to the door slab alone. The entire door assembly is tested and rated together: the door leaf, the frame, the latching mechanism, hinges, closers, seals, and any fire-rated glass in the opening. Every component has to match. If one part isn't approved/listed, the whole assembly may lose its certification. That’s why these systems are technologically advanced, designed to withstand high temperatures and slow down the spread of smoke and flames. Still, they are not fireproof - that’s important to remember.

How Are Doors Rated for Fire Resistance?

In Canada, fire-rated products are tested to CAN/ULC-S104, the Canadian standard for fire tests of door assemblies. Testing is done by recognized laboratories. The products that pass are listed and labeled by organizations such as Underwriters Laboratories of Canada (ULC).

During testing, the door is exposed to extreme heat, usually over 1,000°F, and must remain in its frame with no through-openings and no passage of flames during the test period.

For most ratings, the door also has to pass a hose stream test after the fire endurance test. The door has to stay intact. It aims to reproduce the thermal shock and impact force that the door would experience when firefighters arrive.

A compliant fire-rated door will have a permanent certification label or stamp (often on the hinge edge or top of the door and on the frame), showing:

• The testing/certifying body (e.g., ULC)
• The fire rating (e.g., 20, 45, 60, 90 minutes)
• Any special limitations (for example, “20 minutes, no hose stream”)

If the label is missing, painted over, or unreadable, inspectors may treat the door as not fire‑rated, even if the door was originally certified.

Fire-Rated Doors vs Standard Doors

Fire-rated doors differ from standard door types (e.g., front doors and interior doors) in how they’re built, tested, and certified and in how they perform under fire conditions.

Why Are Fire-Rated Doors Important?

Fire doors don't stop a fire. What they do is slow the spread, contain the smoke, and buy time.

During a fire, building occupants typically have only a few minutes to evacuate safely. A fire-rated door that is correctly installed in the right location can truly slow down the spread of fire and smoke, even if just by a few minutes. That time is what allows people to get out and what allows first responders to get in.

Smoke is the other reason. Smoke inhalation causes the majority of fire-related fatalities. Fire doors are the first barrier keeping smoke from spreading through corridors and stairwells into occupied spaces.

Beyond life safety, fire-rated doors also serve practical purposes:

• Slowing the spread of fire limits structural damage to the building
• Code-compliant door assemblies protect against insurance disputes after a loss
• Buildings without essential protection against fire can fail inspections or face resale complications

Where Are Fire-Rated Doors Required?

Exact requirements come from the National Building Code of Canada, provincial building codes (such as the Ontario Building Code), and provincial/municipal fire codes. The details depend on your building’s use, size, and construction, so always confirm with your local building department or fire prevention office. The list below is meant as a general guide, not a substitute for code approval.

Single-Family Homes or Small Residential Buildings

• Between an attached garage and the living space. Because garages contain fuel, chemicals, and ignition sources, many codes require a fire separation between the garage and the home.
• Utility and mechanical rooms. Mechanical rooms containing furnaces, water heaters, or electrical panels may require rated doors depending on the building layout.

Multi-Unit Residential Buildings

Condo and apartment buildings, student residences, and stacked townhouses have stricter requirements because they house more people and rely on shared escape routes. Common locations for fire‑rated doors in multi-unit residential buildings include:

• Suite entry doors opening onto corridors
• Doors to stairwells and exit stair enclosures
• Doors to garbage rooms, laundry rooms, and storage rooms
• Doors to the mechanical and electrical rooms serving the building

These doors are part of the building’s fire and smoke compartments. They help keep exits usable during an emergency.

Commercial and Industrial Buildings

Commercial applications and industrial buildings face more detailed code requirements based on occupancy classification, building height, and the fire resistance rating of the surrounding wall, whose rating is usually higher than the wall rating. Common locations where fire doors are required include:

• Stairwells. Exit stairwells and vertical shafts require rated doors to contain fire and maintain safe egress routes for building occupants and first responders
• Corridor openings. Public corridors leading to exits require fire doors to control smoke movement and maintain safe evacuation paths
• Mechanical rooms. Boiler rooms, electrical rooms, and storage rooms with elevated fire risk require rated doors based on the wall's fire resistance rating
• Occupancy separations. Where two different occupancy types share a building (e.g., retail and residential), fire separations with rated door assemblies are required
• Schools. Schools have large occupant loads and specific OBC requirements for corridors, classrooms, and service areas

Choosing a Fire Rating: General Guidelines

The “right” rating for a door is not something you can guess yourself. It’s determined by the required fire‑resistance rating of the wall it’s in and by the applicable building and fire codes. In simple terms:

• Lower‑risk locations (like some interior corridors and certain residential applications) often use 20‑minute doors.
• Moderate‑risk locations (many commercial corridors, some stairwells, some occupancy separations) may use 45‑ or 60‑minute doors.
• Higher‑risk or higher‑rise locations (major stairwells, some mechanical rooms, key occupancy separations) may use 90‑minute or higher ratings, often in steel.

For most projects, the designer of record, door supplier, or local Authority Having Jurisdiction (AHJ) will confirm the rating you need for each opening. If you’re replacing a door in an existing rated wall, the safest assumption is that the new door should match the original rating and certification unless a professional tells you otherwise.

The Complete Fire-Rated Door Assembly

This is one of the most important things to understand: the fire rating applies to the complete door assembly, not the door alone. That’s why you can’t easily replace a component of a fire-rated door.

A compliant fire-rated opening typically includes the following components, which are also tested and certified:

• The door leaf – the slab itself, tested and labeled for its fire rating
• The frame – a ULC-certified fire-rated frame that matches the door's rating. Removing or swapping a standard frame can void the assembly.
• Hinges and hardware - hinges, locks, latches, or panic hardware that are approved for use on fire-rated doors
• Self-closing mechanism – a closer or spring hinges so the door closes automatically; fire-rated doors are normally required to be self-closing.
• Latching devices – fire doors must be self-latching. Push/pull plates are generally not permitted on fire-rated door assemblies
• Fire-rated glass – glazing that has its own rating and is approved as part of a rated door assembly; standard tempered glass, for example, is not fire-rated 
• Seals and gaskets – intumescent seals that expand under heat to block smoke and flames from passing through gaps around the door

If any component is removed, replaced with a non-rated part, or improperly modified, the entire fire rating is voided, and your building is no longer code-compliant.

Door Core Materials and Their Fire Ratings

Not all doors are engineered the same way. The core material directly affects what fire rating a door can achieve.

Hollow core doors are not rated for fire protection and cannot be used where a fire-rated assembly is required. If you have hollow core doors in locations that require fire-rated door assemblies, particularly between your garage and home, this is a compliance issue that needs to be addressed.

Steel doors offer the highest available fire rating and are the most durable option for commercial applications, mechanical rooms, and areas with high fire risk. They can also be installed with fire-rated glass lites for visibility where needed.

Wood doors with a mineral core are a popular choice in residential and light commercial settings because they can match the aesthetic of surrounding interior doors while still meeting code requirements.

Fire-Rated Glass in Door Assemblies

If your fire door needs a vision panel (for offices, schools, or anywhere natural light and visibility matter), the glass must be part of the tested and listed fire-rated door assembly.

Standard tempered glass is not fire-rated, for example. Using it in a fire door will normally void the fire rating of the entire assembly.

Fire-rated glass options include:

• Wired glass – available with 20-minute fire ratings; the embedded wire helps hold the glass together under heat.
• Fire-rated ceramic glass – available for 20-minute through 90-minute fire-rated assemblies; allows larger glass areas than wire glass at equivalent ratings.
• Fire-resistant glazing – tested to standards like ASTM E-119 and designed to limit radiant heat transmission as well as flames, allowing larger areas of glass in higher-rated openings.

Fire Door Hardware: What's Required

Every piece of hardware on a fire-rated door needs to be listed/approved for use on fire-rated assemblies (in Canada, that is typically ULC-listed) and installed according to the manufacturer’s instructions.

Typical hardware requirements include:

• Self-closing device – Fire-rated doors are expected to be self-closing so they return to the closed position after each use; this is usually done with a door closer. In some cases, spring hinges are permitted instead on smaller doors if allowed by the door listing and applicable codes. 
• Positive latching device – Fire doors should latch automatically and stay closed under fire conditions; locksets or fire‑rated exit devices can provide this, but simple push/pull plates without a latch are not acceptable on rated openings.
• Listed hinges – Steel, ball‑bearing, or continuous hinges that are labeled for use on fire doors are required; they must be sized and installed in line with the door’s listing.
• Panic/exit hardware (where required) - On doors serving as exits from certain occupancies (such as assembly or high‑hazard areas), codes require panic/exit hardware; fire‑rated exit devices are available and can be used on fire‑rated doors where both egress and fire protection are needed.

For any door that forms part of an exit route, hardware must not restrict egress: occupants must be able to open the door from the egress side without a key, special tool, or complicated sequence of actions. Because of this, double‑cylinder deadbolts, captive keys, or similar locking methods are generally not permitted on doors that serve as required exits or form part of a fire‑rated egress path.

Inspection and Maintenance in Ontario

Annual inspections are widely adopted as a best practice and are often expected in commercial and multi-unit residential buildings. More frequent in‑house checks are encouraged, especially in high‑traffic areas.

During an inspection, the following are checked:

• A valid certification label on the door and frame is present, visible, and not painted over
• Self-closing mechanism functions properly
• Door latches securely on its own
• Seals and gaskets are intact
• Frame is secure and undamaged
• No unauthorized modifications have been made

If any component fails inspection, the building owner is responsible for restoring code compliance. This is not optional. Non-compliant fire doors are a fire safety violation under the OFC.

Property managers and condo corporations are directly accountable under the OFC for the condition of fire doors in common areas. Keep records of inspections and any repairs performed.

How to Choose a Fire-Rated Door for Your Home?

For homeowners, choosing a fire-rated door is mostly about matching the right door type to the right location and making sure it is properly certified as a complete assembly.

Here’s a quick selection guide that can help you make the best choice (but always check local building and fire codes):

FAQs

Are there fire-rated glass doors for residential use?

Yes, modern fire-rated glass doors exist for homes, typically using high-quality, specially treated fire-resistant glazing (such as wired glass or ceramic glass) within a tested frame system. However, they are not very common.

Are fiberglass doors fire-rated?

Some fiberglass doors are fire-rated, but not all. Fire rating depends on the specific door assembly (core, frame, seals, and certification), not just the material.

Are all steel doors fire-rated?

No, not all steel doors are fire-rated. Steel doors are commonly used for fire-rated assemblies, but they are only fire-rated if they are tested and certified as a complete system.

Are all exterior doors fire-rated?

Not all exterior doors are fire-rated. Most exterior residential doors are not fire-rated unless they are specifically required by code or installed in a fire-separation area (e.g., garage-to-house door).

Where are fire-rated doors required?

Fire-rated doors are typically required in fire-rated assemblies such as between a garage and living space, in multi-unit buildings (unit entrances and corridors), stairwells, furnace/utility rooms, and other designated fire separations under building codes.

What is considered a fire-rated door?

A fire-rated door is a door assembly (door, frame, hardware, and seals) that has been tested and certified to resist fire for a specified time period (e.g., 20, 45, 60, or 90 minutes) under standardized testing conditions.