Fireproof ducts have the same basic structure as normal duct systems like other duct systems, but they have been treated with layers of fireproof insulating material on the surface of the ductwork. This layer of material helps the duct to be able to withstand the impact of fire for a certain period of time.

EI ductwork structure:

  • Layer 1: Galvanized corrugated iron layer; minimum thickness 0.75mm
  • Layer 2: Primer layer: (paint to treat the surface of corrugated iron, zinc, …) to create roughness in order to increase the ability to adhere and bond between layers of materials with the corrugated iron surface of the duct. The reinforced wire mesh layer helps the connection between the layers of materials and is more durable. Note: Depending on the size of the duct, it will be used accordingly.
  • Layer 3: Central insulation fireproof layer
  • Layer 4: The outermost layer is fireproof paint

Conditions for construction of EI ductwork system:

  • Condition:
    – The surface of the material must be cleaned of grease and dirt
    – It is recommended to apply when the air temperature is >10 degrees Celsius and the air humidity is <85%, no rain, splash water on the surface.
  • Thickness required protective layers
    The total thickness of the constructions must be according to the norm and meet the selected fire resistance standard.
  • Dry time:
    – Temperature: The lower the temperature, the longer the drying time.
    – Air humidity: The higher the air humidity, the longer the drying time, should not be applied while the air humidity is > 85%.
    – Air circulation: In well-ventilated areas will dry faster.
    – Coating thickness: Depending on the material coating thickness, drying time varies.
    – Construction method: It is recommended to limit construction in conditions of low temperature, high humidity, low air circulation.


The EI ductwork system has an extremely important role: fire prevention, fire control, toxic gas removal and smoke extraction in fire areas. With this requirement, the design and installation of fireproof ductwork is very important to protect the safety of human life and property.



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