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 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 wide; JU-061 at 25–45kg to 850mm; JU-073 at 40–65kg to 850mm; JU-088 at 40–65kg to 950mm; JU-072 at 40–65kg to 1050mm; and JU-093 at 45–85kg to 1050mm. All are aluminium 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.

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.