Understanding the Difference Between EI1 and EI2 Fire Resistance Classifications for Steel Doors


What Do EI1 and EI2 Stand For?

Both EI₁ and EI₂ are part of the European classification system for fire-resistant doors, based on the EN 13501-2 standard. This system evaluates a door’s performance in terms of two critical criteria:

  • E (Integrity): The door’s ability to prevent flames and hot gases from passing through.
  • I (Insulation): The door’s ability to limit the temperature rise on the unexposed side.

The numbers following EI₁ and EI₂ represent the duration in minutes that the door maintains its integrity and insulation properties during a fire. An example being, EI₂60 (60 minutes integrity and insulation).

EI1 and EI2 Fire Doors:

1. EI1 Doors:

  • Higher Insulation Standard: EI₁ doors offer a higher level of fire insulation performance. They maintain the temperature on the unexposed side of the door and frame at a lower threshold compared to EI₂ doors.
  • Temperature Limits: EI₁ doors limit the temperature rise to an average of 140°C and a maximum of 180°C at any point on the unexposed side.
  • Applications: Required in specialist applications for maximum protection. EI₂ is a more commonly requested application across Europe.
  • Thermocouples Positions: They are positioned 25mm from the edge of the leaf and are influenced more aggressively by heat conduction.

2. EI2 Doors:

  • Standard Insulation Level: EI₂ doors have a standard level of fire insulation performance, which is slightly less stringent than EI₁.
  • Temperature Limits: EI₂ doors allow for higher temperatures on the unexposed side, with an average rise of 140°C and a maximum of 180°C at any point.
  • Applications: Often used in more general applications which require fire insulation performance.
  • Thermocouples Positions: They are positioned 100mm from the edge of the leaf.

Additional Information:

  • Testing Standards: Both types of doors are tested according to EN 1634-1: 2014 + A1: 2018 and classified according to EN 13501-2: 2023.
  • Construction: Both door types are constructed from materials that ensure integrity and insulation but differ in the specifics of their thermal insulation capabilities.
  • Missing Subscripts: If the subscript 1 and 2 are missing, you can assume performance relates to EI₂.
  • EI Rating: Likewise, walls can be classified to be rated EI60, although the 1 and 2 subscripts are only applicable to doors.

Example from EBD Steel Doors – EBD65-FireEI:

  • Classification: EI₂ fire resistance performance up to 60 minutes.
  • Construction: Hot dipped galvanised steel with a thermal insulating core.


table explaining EI1 vs EI2
Illustration of thermal couples on a door during a fire test

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