Double Fire Door Regulations: Ratings, Meeting Stiles and When They Are Required

Double fire doors — a pair of fire-resisting leaves hung in one frame — turn up wherever an opening is too wide, too busy, or too important for a single leaf. Hospital corridors, care home escape routes, school halls, commercial entrances and plant rooms all rely on them. But a double fire doorset is not simply two single doors side by side; the point where the two leaves meet is a tested detail, and getting it wrong is one of the most common ways a "fire door" turns out not to be one. This guide explains when the regulations call for double doors, what rating they need, and what makes a certified pair compliant. You can browse our double fire doors for the standard configurations, or compare the trade-offs in our guide to single versus double fire doors.

When are double fire doors required?

There is no single regulation that says "use double doors here". Instead, the requirement falls out of the clear width a door has to provide. Approved Document B of the Building Regulations, supported by BS 9999 for commercial buildings, sets minimum clear opening widths for escape routes based on the number of people who may need to use them. Once the required width exceeds what a single leaf can sensibly deliver — a single leaf much wider than about 1000mm becomes heavy, slow to close and awkward to use — a double or leaf-and-a-half doorset becomes the practical answer.

Double doors are also specified where wide access is needed for everyday reasons: moving beds and equipment through a hospital, manoeuvring a bariatric wheelchair or evacuation sledge in a care home, or simply handling high two-way footfall in a busy building. The fire strategy and the access requirements are decided together, but the door must still meet the fire-resistance period the strategy demands.

Fire rating: FD30 vs FD60 double doors

A double fire door carries the same FD ratings as a single — most commonly FD30 (30 minutes) or FD60 (60 minutes), with an S suffix (FD30S / FD60S) where cold-smoke control is required, which is the norm on escape routes. The crucial principle is that the rating belongs to the complete certified doorset as it was tested: both leaves, the frame, the seals, the meeting stile and all the ironmongery, assessed together to BS 476 Part 22 or BS EN 1634-1. If you are unsure which period your project needs, our FD30 vs FD60 guide walks through the decision.

The meeting stile: what makes a pair fire-rated

The meeting stile — the vertical line where the two leaves come together — is the single biggest difference between a pair and two singles, and it is where uncertified "double doors" fail. In a tested pair, that junction is protected: the leaves are either rebated (one overlaps the other) or square-edged with an astragal cover strip, and intumescent seals are run along the meeting stile so that, in a fire, the gap between the leaves is sealed as the intumescent expands. You cannot recreate this reliably by hanging two single fire doors in a wide frame, because the meeting-stile detail was never part of their test. Always specify a doorset certified as a pair, and check that the certification covers the exact configuration you are buying — a point our fire door certification guide explains in full.

Closers and the closing sequence

Both leaves of a double fire door need their own controlled self-closing device to BS EN 1154, because each leaf must close and latch on its own. Where the leaves are rebated, they also have to close in the correct order — the rebate means one leaf must shut before the other or they will clash and leave a gap. This is the job of a door selector (coordinator) device certified to BS EN 1158, which holds one leaf back until the other has closed. Where the doors are routinely held open for access, that must be done with electromagnetic hold-open devices to BS EN 1155 wired into the fire alarm, never with wedges. Choosing the right closers is covered in our guide to self-closing devices.

Equal pairs versus leaf-and-a-half

Not all pairs are symmetrical. An equal pair has two leaves of the same width and suits openings that genuinely need the full width in regular use. A leaf-and-a-half (or unequal pair) has one normal-width active leaf used day to day, plus a narrower secondary leaf that is normally held shut by flush or shoot bolts and only opened when wide access is needed. The leaf-and-a-half is popular on escape routes because it gives an everyday door that closes reliably, with the extra width available on demand. On any pair, the bolts and hardware on the inactive leaf must be appropriate to a fire doorset and covered by its certification.

Certification and documentation

Because a pair is tested as an assembly, the documentation matters even more than on a single door. Insist on the Declaration of Performance and the third-party certification for the doorset as a pair, confirm the meeting-stile and ironmongery details match what you are buying, and cross-check the reference against the scheme's register. Correct fitting is just as critical — a perfectly made pair can be compromised by poor installation — which is why we cover it in our guide to fire door installation. Keep all of this on file as part of the building's records; under the Building Safety Act's golden thread, it will be asked for.

For standard openings we supply certified FD30 and FD60 double doorsets, and for anything non-standard we build certified made-to-measure pairs to the exact size and configuration. Request a quote with your opening sizes, or contact us and we will confirm the right specification leaf by leaf.