According to the European regulation EN-1634, fire-rated doors are labelled like this: EI2 t-C5. Each of these characters has a meaning and it is the following:
E: Refers to the integrity of an element, or its capacity to bear the fire effects on one of its sides, without transferring the fire to the non-exposed side due to flame or gas escape.
I: Isolation or capacity of an element to bear the fire on one of its sides without allowing the fire to expand to the other side due to heat transference.
• Isolation I1: Average 140ºC, Maximum 180ºC. Measuring 25mm away from the leaf and frame at 180ºC.
• Isolation I2: Average 140ºC, Maximum 180ºC. Measuring 100mm away from the leaf and frame at 360ºC.
T: Time of fire resistance or fire rating of the door in minutes.
C5: Automatic closure durability (200.000 cycles of aperture and closure).