The short answer
- FD means fire door. The number is the minutes it held back fire in a lab test.
- FD30 holds back fire for 30 minutes. FD60 holds it back for 60 minutes.
- The S means smoke seals. An FD30S also limits the cold smoke that gets past it.
- Most homes, flats and offices use FD30 or FD30S. FD60 is used where the fire strategy needs more time, such as some stair cores and plant rooms.
- The rating only counts if the whole doorset is fitted and kept as it was tested.
FD30 vs FD30S vs FD60: What the Codes Mean
Every fire door rating follows the same pattern. “FD” stands for fire door. The number is how many minutes the door held back fire in a lab test. An “S” on the end means it also has smoke seals.
So FD30 is a 30-minute fire door, FD30S is a 30-minute fire door with smoke seals, and FD60 is a 60-minute fire door. FD90 and FD120 exist, but they are rare in homes and offices.
What Does FD30 Mean on a Fire Door?
An FD30 door kept fire from getting through for at least 30 minutes in a standard furnace test. That is called integrity: no flames or hot gas passing through the door or round its edges.
Thirty minutes is enough for most buildings, as it gives people time to escape and firefighters time to arrive. That is why most internal fire doors in homes, flats, HMOs, schools and offices are FD30.
What Does the S in FD30S Mean?
The S means the door has smoke seals and has passed a test that limits how much cold smoke leaks past it. Smoke seals are usually brushes or rubber fins set into the frame or door edge.
This matters because smoke, not flame, causes most harm in a fire. In the early stages, before the intumescent strips have swollen, cold smoke can drift through the gaps and fill an escape route. Smoke seals stop that.
You will often see FD30S on flat front doors, doors onto shared stairs, kitchen doors in HMOs and doors along escape corridors.
When Do You Need an FD60 Fire Door?
An FD60 door holds back fire for at least 60 minutes in the test. It is used where a building’s fire strategy needs more time, for example to protect a stair that is the only way out of a tall building.
- Doors between fire compartments in larger buildings.
- Some doors onto protected stair cores and lift lobbies.
- Plant rooms, boiler rooms and some electrical rooms.
- Some doors onto service risers and stores.
You cannot choose FD60 just to be safe in every case. The rating should match the building’s fire strategy, which comes from Building Regulations and the fire risk assessment. Fitting the wrong rating can still leave you non-compliant.
FD30, FD30S and FD60 Fire Doors Compared
| FD30 | FD30S | FD60 | |
|---|---|---|---|
| Fire resistance | 30 minutes | 30 minutes | 60 minutes |
| Smoke seals | No | Yes | Only if FD60S |
| Typical uses | Most internal fire doors | Flat front doors, stair and kitchen doors | Stair cores, plant rooms, compartment walls |
| Typical thickness | Around 44 mm | Around 44 mm | Around 54 mm |
| Guide price, supplied and fitted | £550–£950 | £1,100–£1,900 as a flat front door | £800–£1,300 |
Thickness varies by maker. Prices are guide prices before VAT and depend on size, glass and hardware.
Which Fire Door Rating Does Your Door Need?
| Door | Typical rating | Notes |
|---|---|---|
| Flat front door onto a shared stair or corridor | FD30S, self-closing | Protects the shared escape route |
| HMO bedroom door onto the escape route | FD30 or FD30S, self-closing | Council licence conditions decide |
| HMO or flat kitchen door | FD30S, self-closing | Kitchens are where most house fires start |
| Office corridor or cross-corridor door | FD30S | Often on hold-open devices |
| Hotel bedroom door | FD30S, self-closing | Guests sleep in unfamiliar buildings |
| Stair core door in a tall building | FD30S or FD60S | Set by the fire strategy |
| Plant room or boiler room | Often FD60 | Higher fire load behind the door |
| House with one family | Often none | Except some loft conversions and garage doors |
Always follow your building’s fire strategy or fire risk assessment. For shared houses, see HMO fire door requirements.
How Fire Door Ratings Are Tested
Fire doors are tested in a furnace as a complete doorset: door, frame, hinges, seals, glass and hardware together. The result only covers that exact set-up.
| Standard | What it tests | How results are shown |
|---|---|---|
| BS 476-22 | Fire resistance (the British standard) | FD30, FD60 and so on |
| BS EN 1634-1 | Fire resistance (the European standard) | E30, E60, or EI30 if insulation is also met |
| BS 476-31.1 | Smoke leakage (the British standard) | Adds the S, as in FD30S |
| BS EN 1634-3 | Smoke leakage (the European standard) | Adds Sa, as in E30 Sa |
Most fire doors sold in the UK are also third-party certified, for example under BM TRADA Q-Mark or Certifire. Certification checks that every door made matches the one that passed the test.
How to Tell a Fire Door’s Rating
- 1
Look for a label or plug
Most certified fire doors have a label or coloured plug on the top or hinge edge. It names the scheme and the rating.
- 2
Check the paperwork
New doors should come with a certificate and fitting instructions. Ask the fitter or the previous owner.
- 3
Look at the seals
A continuous strip round the edges suggests a fire door. A brush or fin seal suggests an S rating.
- 4
Ask an inspector
If there is no label and no paperwork, a trained inspector can check the door and advise on certifying or replacing it.
FD30, FD30S and FD60 Fire Door Costs
| Item | Guide price | Charged |
|---|---|---|
| FD30 internal doorset, supplied and fitted | £550–£950 | per door |
| FD30S flat entrance doorset, supplied and fitted | £1,100–£1,900 | per door |
| FD60 doorset, supplied and fitted | £800–£1,300 | per door |
| Made-to-measure FD30 doorset, fitted | £900–£1,800 | per door |
| Made-to-measure FD60 doorset, fitted | £1,200–£2,400 | per door |
| Fire door leaf into a sound, matched frame | £350–£650 | per door |
Guide prices before VAT, last checked October 2026. Your quote is fixed after a visit or survey.
Glass panels, special finishes, security locks and non-standard sizes all add to the price. See fire door installation in London and made-to-measure fire doors in London.
Fire Door Rating Myths
“A thick door is a fire door”
A solid door is not a fire door unless it was tested and certified. Weight alone proves nothing.
“FD60 is always safer”
FD60 is only needed where the fire strategy asks for it. Fitting it badly is worse than a well-fitted FD30.
“Any hinges will do”
Hinges, closers, locks and glass must all be allowed by the door’s test evidence, or the rating is lost.
“The rating lasts forever”
Damage, gaps, painted seals and missing closers can make any rated door fail. Regular checks keep it working.
Fire Door Rating Questions
How is an FD30 door different from an FD60 door?
An FD30 door held back fire for at least 30 minutes in a lab test, and an FD60 for at least 60 minutes. FD60 doors are usually thicker, heavier and dearer. They are used where the building’s fire strategy needs more time, such as some stair cores.
What does the S mean in FD30S?
The S means the door has smoke seals and has passed a test that limits cold smoke leaking past it. Smoke seals stop smoke spreading in the early stages of a fire, before the intumescent strips swell.
Is FD30S better than FD30?
It gives the same fire resistance, plus protection against cold smoke. On escape routes, flat front doors and kitchen doors, FD30S is usually what is needed. Inside rooms off a protected route, FD30 may be enough.
Do flat front doors need to be FD30S?
In most blocks of flats and converted houses, yes. The flat front door protects the shared escape route from a fire in the flat, so it is usually expected to be a self-closing FD30S door.
What is E30 Sa?
E30 Sa is the European way of writing a similar rating to FD30S. E30 means 30 minutes of integrity under BS EN 1634-1, and Sa means it passed the smoke leakage test under BS EN 1634-3.
Can I upgrade an FD30 door to FD60?
Not usually. A fire door is tested as a whole set, and adding parts to an FD30 door does not make it FD60. If a door needs to be FD60, it should be replaced with a certified FD60 doorset.
How long does an FD30 door last in a real fire?
It depends on the fire and the door’s condition. FD30 means it met the 30-minute standard in a test. A well-kept door in good condition should perform close to that. Gaps, damage or missing closers can make it fail much sooner.
How thick is an FD30 fire door?
Most FD30 doors are around 44 mm thick and most FD60 doors around 54 mm, but it varies by maker. Thickness alone does not prove a rating, so always check for a label or certificate.