If you have been told you need a fire door, the next question is usually which one. FD30 and FD60 are the two ratings you will come across most, and the difference is not just a bigger number. Here is what each rating means in practice, where Building Regulations expect one or the other, and how to check what is already in your home.
The FD stands for fire door and the number is the time in minutes the complete doorset is designed to hold back fire when tested to BS 476 Part 22 or the European standard BS EN 1634-1. An FD30 door resists fire for a minimum of 30 minutes; an FD60 holds for at least 60. That time covers the whole assembly, so the door leaf, the frame, the intumescent strips, the hinges and the closer all have to perform together.
The rating only applies to integrity, which means stopping flames and hot gases passing through. Neither rating promises to keep the other side cool. If you see FD30s or FD60s with an s on the end, that adds cold smoke control, usually through a brush or blade seal fitted alongside the intumescent strip. For flats and shared hallways, the s version is often the one the fire risk assessment will ask for.
Physically, a typical FD30 leaf is around 44mm thick, while most FD60 leaves are around 54mm. The extra thickness comes from a denser core and, in many cases, a heavier construction. An FD60 leaf can easily weigh 45 to 60kg, which is why it needs three or four fire rated hinges and a stronger frame.
For most ordinary homes, FD30 is the standard. Approved Document B of the Building Regulations calls for FD30 doors on habitable rooms opening onto a protected stairway in houses of three or more storeys, including loft conversions in the Victorian and 1930s terraces common across Croydon, Purley and South Norwood. Integral garages also need an FD30 door, ideally self closing, between the garage and the house.
FD60 is more often specified where the consequences of failure are higher. Flat entrance doors in purpose built blocks and converted houses are frequently FD30s, but doors between a flat and a communal riser, plant room or bin store, and doors protecting the only escape route in taller buildings, can be FD60. Commercial premises, HMOs with more than a couple of storeys and buildings with sleeping risk above a workplace often see FD60 doors specified by the fire risk assessor.
The honest answer is that the rating should come from the building's fire strategy or fire risk assessment, not from a guess. If you are a landlord in a converted house in the CR0 or CR2 area, the assessment for the common parts will usually state exactly what each door needs to achieve.
Most certified fire doors carry a label or a small coloured plug on the top edge of the leaf. Certifire and BM TRADA Q-Mark are the two schemes you will see most in the UK, and the label will state the rating. If the top edge has been painted over, a careful scrape with a blade will usually reveal it. No label does not automatically mean the door is not fire rated, but it does mean nobody can prove that it is, and a fire risk assessor will treat it accordingly.
Thickness is a useful clue but not proof. A 44mm door with no intumescent strip in the frame, standard butt hinges and a hollow sound when knocked is almost certainly a plain internal door. Genuine fire doors feel solid and heavy, and the frame will have a groove for the strip either in the door edge or the frame rebate.
Remember that a fire door is only as good as its installation. Gaps around the leaf should be 2 to 4mm at the sides and top, and no more than 8 to 10mm at the threshold unless a drop seal is fitted. Bigger gaps, missing strips or a closer that does not shut the door fully into the latch can reduce a nominal FD60 to something that fails in a few minutes.
Because the leaf is thicker and heavier, an FD60 costs more than an FD30 at every stage. A basic FD30 leaf might start from around £100 to £200 for a plain veneered or primed door, whereas a comparable FD60 leaf is more often £250 to £450 and upwards. Add the frame, ironmongery, seals and fitting and a fully installed FD30 doorset in a house typically lands somewhere in the low to mid hundreds, with FD60 doorsets often several hundred pounds higher. Glazing, bespoke sizes and decorative finishes push both upwards.
Upgrading an existing door from FD30 to FD60 is rarely straightforward. The frame, hinges, closer and often the wall build up around the opening all have to match the higher rating, so in practice it usually means a new doorset rather than a heavier leaf hung in the old frame. Fitting FD60 where FD30 is required is not wrong, but it adds weight, cost and a stiffer closer for no regulatory benefit.
Whichever you need, ask for the test evidence or certification for the specific door and frame combination being fitted, and keep it with your property paperwork. It is what a fire risk assessor, a buyer's surveyor or a housing officer will ask to see.
Not in a simple sense. It holds back fire for longer, which matters where escape takes more time or the risk is higher, but a well fitted FD30 with intact seals will outperform a badly fitted FD60. The right rating is the one your fire risk assessment or Building Regulations specify.
Usually only on the door between an integral garage and the house, and sometimes to a kitchen in an open plan layout as part of a wider fire strategy. Once you add a third storey, such as a loft conversion, FD30 doors on the escape route become a requirement.
Yes, the face of the leaf can be painted or varnished without affecting the rating. Avoid painting over the intumescent strips or the certification label on the top edge, and never plane the door down to make it fit, as that removes the tested edge detail.
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