Surviving a fire is often less about the flames than about a door kept closed. If the door of a burning room is designed to withstand fire, the flames and lethal smoke cannot pass into the corridor; the stairwell stays clear, the escape route remains open, and critical minutes are won until the fire brigade arrives. That is why, in certain locations, regulations permit not an ordinary steel door but a certified fire door. Yet in the market a "steel door" and a "fire door" are frequently confused; the two are distinct products in terms of design, materials, testing, and legal liability. This guide explains the EI classes, where such a door is mandatory, and which documents are considered valid.
A Steel Door and a Fire Door Are Not the Same Thing
A standard security steel door is designed against burglary and forced entry; its performance is measured by an RC resistance class under TS EN 1627. A fire door, by contrast, is designed against flame and heat; its performance is measured by the EN 1634-1 test and classified in EI minutes. A door being robust against forced entry does not automatically make it a fire door.
What creates the difference lies in details you cannot see. In a fire door, the core between the steel skins is not polyurethane but non-combustible mineral rock wool; around the leaf, intumescent seals that expand with heat and seal off gaps are fitted. The frame, leaf, hinges, lock, and glazing are tested together as a system; it is the certification of the assembled whole, not of a single part, that is valid.
EI Classes: What Do EI30, EI60, EI90, EI120 Mean?
Fire-door performance is expressed with a letter-and-number code. The letter indicates which property the door provides, and the number shows for how many minutes it sustains it:
- E (Integrity): The time the door prevents flames and hot gases from passing to the other side.
- I (Insulation): Limiting heat transfer; ensuring the surface facing away from the fire does not reach a dangerous temperature.
- S (Smoke): An additional property limiting smoke leakage around the edges; indicated as "Sa" or "S200".
Accordingly, EI30 maintains both integrity and insulation for about 30 minutes, EI60 for 60, EI90 for 90, and EI120 for 120. The required duration is not chosen arbitrarily; the fire design determines it according to the building's height, occupancy class, and compartment resistance, and it rises as the risk increases.
Where Does the Regulation Make the Door Mandatory?
In Turkey, the legal framework is set by the Regulation on the Protection of Buildings Against Fire (BYKHY), which requires escape routes to be protected from fire and smoke; in practice this means a certified fire door. The typical mandatory points are:
- Escape stairs and protected corridors: So that the stairwell stays free of smoke, the entrance doors must be fire-resistant and of the self-closing type.
- Compartment transitions: Doors in partition walls must be of an EI class compatible with the resistance of that wall.
- Boiler rooms, generators, transformers, and enclosed car parks: These spaces, which carry a high fire load, are separated from interior areas by a fire door.
- Hotels, dormitories, hospitals, and high-rise buildings: Because they hold many occupants with limited mobility, compartmentalization of corridor and stair entrances is mandatory.
The obligation does not end with merely "a fire-resistant leaf"; the regulation also requires the door to open in the direction of escape, to be self-closing, and, where necessary, to operate with panic hardware.
Closing, Panic Bars, and Smoke Sealing
A fire door is only useful if it is closed at the moment of the fire; an EI120 door left open has no protective value. That is why the hardware accessories are indispensable.
Door Closer (Hydraulic Arm)
So that fire doors do not remain open, they are equipped with a self-closing hydraulic closer. If the passage is meant to stay open under normal conditions, an electromagnetic hold-open device linked to the fire alarm is used: when the alarm sounds, the hold is released and the door closes automatically.
Panic Bars and Smoke Sealing
At exits where a crowd must evacuate quickly, the door must be openable from the inside with a single movement and without a key; EN 1125-compliant panic bars provide this. Where the entrance must be controlled, EN 179 emergency exit locks are used instead. Because a significant share of fatalities are caused by smoke, at many points EI alone is not enough; cold-smoke seals (Sa) and high-temperature sealing (S200) stop the smoke and are marked on the label as, for example, "EI60-Sa".
Certification, Labelling, and CE: Which Document Is Valid?
A door's fire resistance can only be proven by a real fire test conducted in an accredited laboratory; it cannot be assessed by eye, and a verbal claim that something "is fire-resistant" has no legal weight. The documents to look for are:
- Test / classification report: Shows that the door underwent the EN 1634-1 test and was classified according to EN 13501-2 (e.g. EI60).
- CE marking and Declaration of Performance (DoP): As a construction product, a fire door is placed on the market with CE marking and a declaration of performance.
- Permanent identification label: Carries the manufacturer, the model, and the EI class; a door without a label will be questioned during inspection.
The most common mistake is invalidating the certification by incorrectly installing a door that has passed testing. The certificate belongs to the tested frame-leaf-hinge-lock-installation assembly; replacing a hinge with an untested product, mounting it on the wrong frame, or filling the gaps with non-fire-rated foam renders the door uncertified and creates serious liability for the building management.
Işıldak Çelik Kapı manufactures both standard security doors and fire-resistant door solutions suited to project requirements at its production facility in Sancaktepe, Istanbul; serving Istanbul and the European Side with delivery, during a free site survey our expert team assesses on-site, together with you, the EI class and hardware needs appropriate to your fire design.
Frequently Asked Questions
Can I use my standard steel door as a fire door?
No. A standard security steel door is designed against burglary and assessed under TS EN 1627/RC; because it has not passed a fire test (EN 1634-1), it has no EI class. In places where the regulation requires a fire door, a certified, labelled fire door of the appropriate EI class must be used.
How is it decided which EI class to choose?
The EI class is not chosen arbitrarily; the fire design and the project author determine it according to the building's height, intended use, and compartment resistance. As the structure grows and the risk increases, a higher minute value is required; that is why the approved fire design should be consulted before procuring the door.
