Every commercial building in Ontario has doors that are doing more than letting people in and out. Some of them are quietly holding back fire and smoke long enough for everyone to get out and for crews to arrive. When one of those doors is missing a closer, propped open with a wedge, or fitted with the wrong hardware, it stops doing that job, and a routine inspection can turn into an order to fix it before you reopen.
Fire door rules in this province come from two places: the Ontario Building Code, which governs how a building is designed and built, and the Ontario Fire Code, which governs how it has to be maintained once people are using it. The two overlap, and property managers get tripped up where they meet. This guide walks through what the codes actually ask for, in plain terms, so you can look at your own doors and know whether they measure up.
Quick answer: Under the Ontario Building Code, a fire door is a tested and labelled door assembly installed in a fire separation to slow the spread of fire and smoke. It has to carry a fire-protection rating matched to the wall around it, close and latch on its own, and stay free of field modifications. The Fire Code then requires that assembly be kept operational for the life of the building.
What counts as a fire door
A fire door is not one part. It’s an assembly, and every piece of it is part of the rating. The door leaf, the frame, the hinges, the latch, the closer, and any glazing all have to be listed and compatible. Swap in a hardware-store hinge or cut a new vision panel on site, and the whole assembly can lose its listing even though the door still looks fine.
That assembly gets tested as a unit. In Canada the reference test for doors is CAN/ULC-S104, “Fire Tests of Door Assemblies,” which is the standard the Building Code points to when it sets ratings. Windows and glass block are tested to CAN4-S106-M, and fire dampers to CAN/ULC-S112. A door that passes carries a label showing its rating, and that label is your proof the assembly is what the code expects.
The parts of a fire door assembly
| Component | What it does in a fire | Why it fails inspection |
|---|---|---|
| Door leaf | Blocks flame and heat for its rated time | Holes, unfilled cutouts, missing label |
| Frame | Holds the leaf square and anchored to the wall | Loose anchors, damage, wrong frame type |
| Hinges | Keep the door aligned under heat | Non-listed hinges, worn or loose screws |
| Latch | Holds the leaf shut against pressure | Disabled latch, taped strike, no positive latching |
| Closer | Returns the door to closed on its own | Removed, leaking, or won’t close fully |
| Glazing | Lets light through while resisting fire | Non-rated glass, oversized lite |
If a door in your building is losing its alignment or dragging, that’s worth reading about before it turns into a code problem. Our guide on why a commercial door starts grinding covers the early warning signs, and commercial door hinge replacement matters more on a fire door than most people expect, because the hinges have to be listed for that assembly.
Fire-protection rating and fire-resistance rating are not the same thing
This is the distinction that confuses almost everyone. A fire-resistance rating belongs to the wall, floor, or fire separation. A fire-protection rating belongs to the closure, meaning the door, window, or damper in that separation. The wall and the door are rated on different scales on purpose, because an opening with a self-closing door behaves differently in a fire than a solid wall does.
So a two-hour fire separation does not need a two-hour door. The code sets a matched value instead, and that value is lower than the wall’s own rating. The table below is the one that governs it.
How the required rating is set
The Building Code determines a closure’s rating through the CAN/ULC-S104 test, and then Article 3.1.8.4 ties the required closure rating to the fire-resistance rating of the separation it sits in. Here is that relationship.
| Fire-resistance rating of the separation | Required fire-protection rating of the door |
|---|---|
| 30 minutes | 20 minutes |
| 45 minutes | 45 minutes |
| 1 hour | 45 minutes |
| 1.5 hours | 1 hour |
| 2 hours | 1.5 hours |
| 3 hours | 2 hours |
| 4 hours | 3 hours |
Source: Ontario Building Code, Table 3.1.8.4. Always confirm against the current edition of the Code for your project.
There’s also a common shortcut in the code for lower-rated situations. A 20-minute door is allowed as the closure in certain fire separations rated no higher than one hour, such as between a public corridor and a suite, and generally in buildings up to three storeys where the separation is rated no more than 45 minutes. That’s why you’ll see 20-minute doors on corridor-to-office openings while a stair or service room down the hall carries a heavier rating.
Reading a rating off a wall drawing is one thing. Knowing whether your existing doors still match is another, and it’s exactly the kind of gap we walk through in our post on whether your current doors meet the Ontario Building Code.
Clearances and gaps: the small numbers that fail doors
A fire door only performs if it fits its frame tightly. Too big a gap and hot gases push through; too tight and the door binds and won’t latch. For the 20-minute closures the Building Code describes, the door has to have a clearance of no more than 6 mm at the bottom and no more than 3 mm at the sides and top. Those are small tolerances, and they drift over time as buildings settle and hardware wears.
This is one of the most common findings on an inspection, and it’s usually fixable without replacing the door. A technician can adjust the frame, swap worn hinges, or correct a sagging leaf so the gaps come back into range. When a door has dropped far enough that it scrapes the floor or won’t catch the latch, that’s the point to book commercial metal and fire-rated door repair rather than wait for it to be written up.
Hardware the code expects on a fire door
A fire door has to close and latch by itself, every time, with no one thinking about it. That single requirement drives most of the hardware rules.
Self-closing devices
Every fire door needs a closer that returns it fully to the closed position from any open angle. If a closer is leaking oil, sticking, or has been removed because it slammed too hard, the door is non-compliant even if it looks normal. A worn closer is easy to underestimate, and we get into the real cost of leaving one alone in our piece on ignoring a failing commercial door closer.
Positive latching
Closing isn’t enough. The latch has to engage so the door stays shut against the pressure a fire builds. Taping over a latch, disabling it for convenience, or leaving a strike plate that no longer catches all defeat the assembly. On exit doors this ties into panic hardware, which has to both allow instant egress and latch positively behind the last person out.
Hold-open devices
Plenty of fire doors are legitimately held open during the day, but only with a device that’s tied to the fire alarm and releases the door on activation. A rubber wedge, a hook, or a fire extinguisher used as a doorstop are all violations, because none of them let the door close when it matters. If you rely on doors staying open for traffic flow, that’s often a good case for automatic door operators paired with alarm-released hold-opens instead of a prop.
Labels, certification, and field modifications
The label on the hinge edge of a fire door is the whole ballgame during an inspection. It identifies the manufacturer, the rating, and the listing agency. If that label is painted over, removed, or illegible, an inspector can treat the door as unrated even if it was compliant the day it was installed. Painters are a surprisingly common cause of this.
Field modifications are the other trap. Cutting a new vision lite, drilling for hardware the assembly wasn’t tested with, or planing the leaf down to fix a rub can all void the listing. When a door genuinely no longer works, the right path is usually a listed replacement rather than a workaround. Our overview of commercial metal and fire-rated door replacement explains when replacement is the cleaner call, and the broader repair versus replacement decision applies here too.
The Fire Code side: keeping doors compliant after opening day
Meeting the Building Code at construction is only half the story. The Ontario Fire Code makes the building owner responsible for keeping fire separations and their closures working for as long as the building is occupied. In practical terms that means the doors get inspected, tested, and repaired on an ongoing basis, and records are kept.
The Fire Code also carries the core egress rule people know: every required exit door has to be arranged so that it opens in the direction of travel when the latch is released, without a key or special knowledge, whenever the building is occupied. A fire door on an exit has to satisfy both goals at once, letting people out instantly while still closing and latching behind them.
A simple maintenance rhythm
| What to check | Looking for | Typical cadence |
|---|---|---|
| Closer operation | Full close from any angle, no leaks | Routine walk-throughs |
| Latch engagement | Positive catch every time | Routine walk-throughs |
| Perimeter gaps | Clearances within tolerance | Annual inspection |
| Label legibility | Rating label present and readable | Annual inspection |
| Hold-opens | Alarm-released, no wedges or props | Routine walk-throughs |
| Clear path | No storage or obstruction at the door | Ongoing |
You can confirm the exact obligations and the current wording in the Ontario Fire Code (O. Reg. 213/07) and the design side in the Ontario Building Code (O. Reg. 332/12), both published by the Government of Ontario.
Common fire door problems and what they mean
| Symptom | Likely cause | What to do |
|---|---|---|
| Door won’t latch | Misaligned strike, worn hinges, sagging leaf | Adjust alignment and hardware |
| Door won’t close fully | Failing closer or binding frame | Service or replace the closer |
| Gap too wide at the sill | Settling, dropped leaf, floor change | Re-hang or adjust to tolerance |
| Label missing | Painted over or removed | Verify listing or replace assembly |
| Propped open daily | Traffic flow, heat, convenience | Fit an alarm-released hold-open |
When a door has failed outright and the building can’t stay secure or code-compliant, that’s an emergency commercial door repair situation, and it helps to know when to call for emergency door repair before a small fault becomes a shutdown.
Choosing the right fire door in the first place
Getting the specification right at the start saves the retrofits later. Fire doors come in hollow metal, mineral-core wood, and rated glazed options, and the choice depends on the rating, the traffic, and the look you need. Hollow metal is the workhorse for stairs, service rooms, and back-of-house openings; rated glass doors show up where a lobby needs light and sightlines.
Material choice interacts with everything else on the building. Our comparison of steel versus aluminum doors is a useful starting point, and if you’re planning a build or renovation, the walkthrough on choosing the right commercial door covers how ratings, sizing, and hardware fit together. Sizing in particular has its own rules, which we lay out in the guide to standard commercial door sizes.
Fire doors, accessibility, and permits
Fire doors have to work alongside accessibility, not against it. A door can be fire-rated and still need to meet clear-width and operating-force expectations for barrier-free access, which is where closer adjustment and operator selection get delicate. We cover the width side in our post on accessible door width requirements.
Replacing or adding fire doors can also trigger permit requirements, especially when you touch a rated separation or change an exit. Before starting work, it’s worth reading when Toronto businesses need permits for door and storefront work so the project doesn’t stall at inspection.
Not sure your fire doors would pass? A quick assessment tells you where you stand before an inspector does. Our team services rated doors across Toronto and the GTA, from a single sticking closer to a full stair-door replacement.
See our commercial door services or contact Commercial Door Pros for a fire door assessment.
Frequently asked questions
What are the requirements for a fire-rated door in Ontario?
A fire-rated door in Ontario must be a tested, labelled assembly with a fire-protection rating that matches the fire separation it sits in. It has to self-close, latch positively, keep its clearances within tolerance, use listed hardware, and stay free of field modifications that would void its listing.
Does a two-hour fire wall need a two-hour door?
No. The Ontario Building Code sets the door’s rating lower than the wall’s. Under Table 3.1.8.4, a two-hour fire separation requires a one-and-a-half-hour door, and a one-hour separation requires a 45-minute door. The door and the wall are rated on different scales by design.
What is the difference between fire-resistance and fire-protection ratings?
A fire-resistance rating applies to walls, floors, and fire separations. A fire-protection rating applies to the closures in them, meaning doors, windows, and dampers. The two are matched through the Building Code, and a closure’s required rating is generally lower than the separation’s own rating.
How wide can the gap around a fire door be?
For the 20-minute closures the Building Code describes, clearance must be no more than 6 mm at the bottom and no more than 3 mm at the sides and top. Gaps that drift outside those limits are a common inspection finding and can usually be corrected by adjustment.
Can I prop a fire door open?
Only with a hold-open device connected to the fire alarm that releases the door on activation. Wedges, hooks, and objects used as doorstops are not allowed, because the door has to be able to close on its own when the alarm sounds.
Do fire doors need to be inspected?
Yes. The Ontario Fire Code makes the building owner responsible for keeping fire separations and their closures operational. In practice that means regular checks of closers, latches, gaps, and labels, along with repairs and records, for as long as the building is occupied.
What voids a fire door’s rating?
Removing or painting over the label, cutting new openings, drilling for untested hardware, planing the leaf, disabling the latch or closer, and installing non-listed hinges can all void the listing. Once voided, the assembly is treated as unrated until it is corrected or replaced.
Where are fire doors required in a commercial building?
Fire doors are required wherever a fire separation exists, which commonly includes exit stairs, corridors, service and mechanical rooms, storage and garbage rooms, and openings between separated occupancies. The specific locations follow the building’s fire separations as designed under the Building Code.
What is a 20-minute fire door used for?
A 20-minute door is permitted in certain lower-rated separations, such as between a public corridor and a suite, and generally in buildings up to three storeys where the separation is rated no higher than 45 minutes. It’s a lighter closure for lighter-rated openings.
Can a fire door have glass in it?
Yes, if the glazing is fire-rated and sized within the limits of the tested assembly. Ordinary glass is not acceptable in a fire door. Rated glazed doors are common in lobbies and entries where light and sightlines matter but a rating is still required.
Who is responsible for fire door compliance?
The building owner. The Ontario Fire Code places the duty to maintain fire separations and closures on the owner, though property managers and facility teams usually handle the day-to-day inspections and coordinate repairs on the owner’s behalf.
Do exterior doors have to be fire-rated?
Not automatically. A door’s rating depends on whether it sits in a fire separation, not on whether it faces outside. Some exterior doors carry ratings because of spatial separation between buildings, while many do not. The building’s fire plan determines it.
Can a fire door be repaired, or does it have to be replaced?
Many issues, such as worn closers, misalignment, and out-of-tolerance gaps, can be repaired without replacing the door. Replacement becomes the better path when the leaf or frame is damaged, the label is gone, or field modifications have voided the listing.
What standard are fire doors tested to in Canada?
Door assemblies are tested to CAN/ULC-S104, “Fire Tests of Door Assemblies,” which is the standard the Ontario Building Code references. Windows and glass block use CAN4-S106-M, and fire dampers use CAN/ULC-S112. A passing assembly carries a label showing its rating.
How do I know what rating my doors need?
Start with the building’s fire separation drawings, which show the rating of each wall. Match those to the required closure ratings in Table 3.1.8.4. If drawings aren’t available, a door specialist or code professional can assess the separations and confirm what each opening needs.
Are fire doors and smoke doors the same thing?
They overlap but aren’t identical. Fire doors resist the passage of flame and heat for a rated time. Smoke control can be an added requirement, calling for gasketing and tighter sealing. Some doors serve both roles, so it’s worth confirming what a given opening is meant to do.
Editor note on images. This article uses three AI-generated illustrative photographs, each 1376 x 768 px PNG, optimized for web and attached to this post. 1) commercial-fire-rated-door-ontario-building-code-hero.png (featured), a grey steel fire door with closer and panic bar in an office corridor. 2) fire-door-clearance-gap-inspection-1.png, a technician checking a perimeter gap with a feeler gauge. 3) commercial-fire-rated-exit-stair-door.png, a fire-rated stair door on a clear egress path. Images are illustrative and can be swapped for site photography. For technical accuracy, a designer-built diagram of a fire door assembly and a labelled version of the ratings table would be strong future additions, since AI image tools are unreliable for precise labels.
Most fire-rated commercial doors are built from steel. Our guide to hollow metal doors explains the gauges, cores, and construction behind fire-rated steel door assemblies.
Fire doors on an exit route often need fire exit hardware, which behaves differently from standard panic hardware. See our guide to panic bars and exit devices for how the two differ and why dogging is not allowed on a fire door.
