E – integrity
E means that in the fire test the door holds back flames and hot gases – on the unexposed side there are no flames or gaps they could pass through. Doors marked only E stop the spread of fire but not the transfer of heat.
I – insulation (I1 and I2)
I means the door limits the temperature rise on the side away from the fire, so the fire cannot spread by igniting things next to the door. There are two ways of measuring:
- I1 – the stricter method, temperature is also measured close to the edge of the leaf
- I2 – the most common marking for steel fire doors in Europe
For most buildings the design requires EI2. If the bill of quantities just says “EI 60”, EI2 60 doors are offered in practice.
The number – minutes of resistance
The number after the letters shows how many minutes the door withstood the test: 30, 60, 90 or 120. A higher class also covers lower requirements – EI2 60 doors can be fitted where EI 30 is required, and EI2 120 doors where EI 90 is required.
Example: EI2 60 = the door holds back flames and hot gases (E) and limits heat transfer (I2) for 60 minutes.
W – radiation
W appears mainly with glazed elements and means that heat radiation through the glass is limited. An EW requirement is less strict than EI – which is why with glazed doors and fire-rated windows it is always checked which class is actually required.
S – smoke control (Sa and S200)
S means the door limits smoke leakage. Sa means testing with cold smoke, S200 also with smoke at 200 °C. It is required on escape routes, stairwells and in hospitals – see smoke-control doors.
C – self-closing (C0 to C5)
C means the door closes by itself, and the number shows how many opening and closing cycles the mechanism withstood in testing. C5 means 200,000 cycles and is required for busy doors, such as entrances to stairwells or corridors.
EI is not the same as A1 or A2
Two different things are sometimes mixed up in bills of quantities. Reaction to fire (classes A1, A2, B, C, D, E and F to EN 13501-1) says how much a material itself burns and contributes to a fire – steel, brick and mineral wool are A1, plasterboard A2, wood usually D. Fire resistance (classes EI 30, 60, 90, 120 to EN 13501-2) says how long a whole element – a door, wall or ceiling – holds back fire and heat.
Doors do not get class A1 but an EI class. The steel and mineral wool in the leaf are non-combustible, but only testing the whole door shows how long it protects.
The same distinction applies to installation: it is not enough for the gap filling to be “non-combustible” – it must be tested with the door, as described in the article on fire door installation.
How to read the whole marking
The marking EI2 60-S200C5 means: for 60 minutes the door holds back fire and limits heat transfer (measured by method I2), also stops hot smoke and closes by itself, with a mechanism tested for 200,000 cycles.
Doors are tested to EN 1634-1 (fire resistance) and EN 1634-3 (smoke), classified to EN 13501-2, and certified as a product to EN 16034. Which documents you receive is described in the article Documents for building inspection.
