Why a Double Fire Door Needs a Coordinator, and How to Size One

A single door closes one way. A pair does not. Put a closer on both leaves of a double door and each one obeys its own spring, its own hydraulic setting and whatever the wind is doing in the corridor at that moment, so the two leaves arrive in whichever order they happen to arrive. On an ordinary pair of doors that is untidy. On a fire door it is the difference between a rated assembly and a hole in a wall.

The reason is the overlap. A double fire door has an astragal or a rebate where the leaves meet, and that overlap belongs to the inactive leaf: the active leaf must close on top of it. If the active leaf gets there first, it lands against the edge of an open inactive leaf and stops. The latch never engages the strike. What you are left with is a door that looks shut, is not latched, and will be pushed open by the pressure difference a fire creates long before the leaf itself fails. Every fire test certificate in the world assumes the door was latched.

A door coordinator is the mechanical answer. It sits across the top of the frame, holds the active leaf back while the inactive leaf completes its swing, and then releases it. There is no power, no signal and no adjustment to drift: an arm is held, then it is let go, in the right order, every time. The Canton Hyland DC02 works this way, zinc-plated steel, 397 × 120mm (4-3/4") across the frame head, supplied with two support brackets and its fixings.

The part that gets specified wrong is the pairing. A coordinator is not an alternative to closers; it is a component that only does anything when both leaves already have one. Three items have to agree with each other: the leaf weight, the closer power on each leaf, and the coordinator's rated range. The DC02 is rated for leaves of 55–100kg. Pick a closer whose capacity band contains the actual leaf weight, then check that the weight sits inside the coordinator's range as well.

From our own closer range, the bands are: JU-051 at 15–30kg on doors to 800mm (31-1/2") wide; JU-061 at 25–45kg to 850mm (33-7/16"); JU-073 at 40–65kg to 850mm (33-7/16"); JU-088 at 40–65kg to 950mm (37-3/8"); JU-072 at 40–65kg to 1050mm (41-5/16"); and JU-093 at 45–85kg to 1050mm (41-5/16"). All are aluminum bodies with a 180° maximum opening angle. The overlap that matters for a coordinated pair starts at 55kg, which is where the DC02's range begins, so JU-072, JU-073, JU-088 and JU-093 are the four that can carry a leaf the DC02 is also rated for.

There is a gap in that list and it is better said than discovered on site: above 85kg we do not currently offer a closer. The DC02 is rated to 100kg, and a 90kg leaf is a real specification on a hardwood or steel-faced fire door, but our heaviest closer stops at 85. If your leaves are heavier than that, the coordinator is not your constraint, the closer is, and we would be specifying past our own range to tell you otherwise. Ask us and we will say so rather than sell you a pair that cannot hold the door.

Two more things decide whether the assembly works, and neither is on the coordinator's datasheet. The first is what else is on the inactive leaf: flush bolts or a two-point lock have to be fully home before the active leaf lands, which is the same sequencing problem one component further down. The second is the closing force after coordination, a coordinator adds a restraint to the active leaf's swing, so a closer set at the bottom of its band to feel light in the hand may no longer have the authority to latch against a seal. Set the closer for the door, then confirm it still latches with the coordinator fitted.

Two kinds of coordinator, and which one your pair takes

Catalogs list coordinators as one line. They are two mechanisms with different failure modes, and the choice is made by the head of the frame rather than by preference.

Bar coordinator: a horizontal bar across the soffit of the frame, held down by the active leaf and released when the inactive one passes. It suits pairs with an astragal on the inactive leaf and needs a frame head deep enough to take the bar without fouling the closers. It is the type most often specified, and the one most often ordered too short, the bar has to span the full clear opening, not the leaf.

Gravity coordinator: a pivoting arm that drops as the inactive leaf closes. It needs less head depth and is the answer where the soffit is shallow or already crowded, but it is more sensitive to being installed out of level. A gravity unit on a frame that has settled will release early.

Both are held down by the active leaf, so both have a weight range of their own, a coordinator sized for a 40kg leaf will be held open by a 90kg one and never release.

The astragal decides more than it looks like it does

installation coordinator bars overlapping astragals double doors is a query that reaches this page, and the phrasing is exact: the astragal is what creates the problem the coordinator solves.

The astragal is the vertical strip that closes the gap at the meeting stile. It is fixed to one leaf and overlaps the other, so the leaves can only close in one order. Three things follow from that and all three get missed.

Which leaf carries it decides which leaf is active: the astragal goes on the inactive leaf and the active leaf closes over it. Get that backwards on the schedule and the coordinator is fitted to hold back the wrong leaf.

Its thickness is the gap you see when the order is wrong: a pair that will not quite close, standing open by three or four millimeters, is almost always an astragal problem rather than a closer problem. Adjusting the closers will not fix it; they are doing exactly what they were set to do.

On a fire pair it is usually intumescent: the strip expands under heat to seal the meeting stile, which means it is part of the rated assembly and cannot be substituted for a plain aluminum one because the plain one fitted. Our page on what a test report actually covers sets out why a substitution inside a tested assembly is a change to the test.

What actually goes wrong, in the order it goes wrong

The coordinator is left off the schedule: the most common failure by a wide margin, and it happens because schedules are written leaf by leaf while a coordinator belongs to the pair. Neither leaf's row has a place for it.

The flush bolts are manual when they should be automatic: the inactive leaf needs holding, and a manual bolt means somebody bends down twice a day. On a fire pair that somebody eventually stops bending, and the inactive leaf is then unsecured.

The closers are set to fight the coordinator: if the active closer is faster than the inactive one, the coordinator is holding back a door that wants to arrive first, it will work, and it will wear. Set the inactive leaf to close first with margin, then set the active one.

Nobody checks it after handover: a coordinator is a moving part above head height that nobody looks at. The check takes five seconds: let both leaves go from fully open and watch the order. If the active one lands first, something is out.

What to send us, and why each field is there

Both leaf weights and widths, because the coordinator and both closers are sized from them. Door thickness, because it sets the astragal and the bolt lengths. Whether the pair is fire rated, because that decides whether anything on the opening can be substituted. And a photograph of the frame head, because that one image answers the bar-or-gravity question faster than any description.

One sentence closes the whole topic. A coordinator belongs to the opening, not to either leaf, so it needs its own line on the schedule, its own weight check against both leaves, and its own five-second test at handover. Every failure above is a version of that line being missing.

What to send us when you ask for a quotation: the leaf weight and width for both leaves, the door thickness, whether the pair is rebated or has an applied astragal, what hardware sits on the inactive leaf, and the fire rating the assembly has to hold. With those we can tell you which closer pairs with the DC02 for your doors, or tell you that your leaves are outside what we make, which is an answer we would rather give before the container ships than after. If you supply fire door hardware to installers, ask for the coordinator, the closers and the panic bars for the same pair in one quotation: all three are sized from the same leaf data.

That is also the cheapest fix available on a double door: one row added to a schedule, before anything is ordered, rather than a return visit with a ladder after handover.