Not a door, an assembly
Treating a fire door as an ordinary door is the most common misunderstanding in this field. It is a matched set designed to work together: leaf, frame, hinges, seals, lock, closer and, where fitted, panic hardware. Swap one component or leave one out and the performance of the rest loses its meaning. That is why the trade talks about a door assembly rather than a door.
The purpose differs too. An apartment door is about security and insulation. A fire door is about buying time — delaying flame and smoke crossing from one fire compartment to the next so that people can evacuate and crews can intervene.
What resistance periods mean
Fire doors are classified by how long they maintain integrity and insulation under fire exposure, and periods such as 30, 60, 90 and 120 minutes are commonly discussed. The figure does not mean the door will not burn; it means that for that period flame passage and heat transmission are held within defined limits.
Nor is the period a property of the leaf alone — the same leaf behaves differently with another frame, seal or glazing. Resistance applies to the complete assembly, installation included.
What is inside
- Leaf: steel skins over a core suited to fire exposure. Mineral wool is widely used because it holds its form at high temperature and slows heat transfer.
- Frame: formed steel profile carrying the leaf and resisting thermal movement, bedded to the wall with non-combustible packing.
- Intumescent seal: an unremarkable strip in normal conditions that swells with heat and closes the gap between leaf and frame. This is the part that limits smoke passage.
- Door closer: returns the door to the latched position after every use. A fire door standing open is an empty frame.
- Hinges and hardware: selected to hold form at elevated temperature, with hinge count set by leaf weight.
- Glazing: where used, fire-rated glass in a heat-resistant frame. Ordinary glass fails in the first thermal shock.
Where they are used
Fire doors sit at the boundaries between a building's fire compartments: stair enclosures, boiler rooms, electrical and generator rooms, the transition between a car park and the building, storerooms and corridor subdivisions. What these have in common is that they separate two spaces carrying different risk.
Doors on escape routes carry an extra requirement: they open in the escape direction, and from inside without a key. Both conditions are independent of fire resistance.
Compared with a normal steel door
In one sentence: one is designed against forced entry, the other against heat and smoke. An apartment door emphasises multi-point locking, leaf thickness and quiet closing. A fire door emphasises core material, seal behaviour, closer performance and escape direction. You cannot substitute an apartment door for a fire door, and while the reverse is technically possible it is impractical, because fire door aesthetics and acoustics are built around a different goal. On projects using both, treat our fire doors and building entrance doors ranges as separate specifications.
They fail quietly
The dangerous thing about a fire door is that it gives no warning when it stops working. A closer losing oil still closes the door, just not into the latch. A worn seal still lets it shut, but smoke now passes.
- Open the door by hand and release it: does the closer drive it into the latch?
- Is the perimeter gap narrow and even, with the seal unbroken?
- Is the door propped open with a wedge, bucket or wire? Remove it immediately.
- If a panic bar is fitted, does one push retract every bolt?
- Is the identification label still legible?
Five minutes once a year keeps a fire door functional. Which resistance period and hardware configuration you need comes from the building design rather than from a catalogue. Send your opening sizes in centimetres, quantities per size and the escape direction for each, and we will quote the assemblies with shipping from Istanbul priced separately.
