How to fireproof steel structures

Updated April 17, 2017

When constructing a steel building, using building materials that are specially designed to reduce the transfer of heat can mean the difference between life and death when a fire starts. The intense heat from a blazing inferno can exceed temperatures of 871 degrees Celsius, causing the structural steel to quickly warp and collapse. While fireproofing does not prevent or contain fires, designing a steel structure with fire safety in mind can help to protect the occupants and the building.

Contact the local building and fire brigade for information concerning regulations, standards and restrictions that may apply to methods or construction materials that will be used. Obtain a permit when you are performing renovations or construction on a steel structure, if required. Plan the fireproofing systems on paper. Note potential fire hazards, such as greasy duct work in a kitchen, and electrical cables.

Check the label of the intumescent paint for warnings and instructions. Apply the intumescent paint to exposed, weight bearing steel supports. Air dry the intumescent paint fully before applying additional layers. Using intumescent paint to coat steel supports can help reduce the transfer of heat from the fire to the metal.

Assemble the form boards around the structural steel posts. Insert the metal mesh and steel rebars in between the form boards. Mix the concrete with water. Pour the concrete into the form boards. Remove the form boards when the concrete has dried and cured.

Choose materials with high fire ratings and features for interior finishes such as doors, windows, flooring and wall boards; these materials are specially designed to resist combustion. Divide long hallways with fire doors to help contain fires within an enclosed area.

Mount a fire alarm on every floor of the building, including basements or storage areas. Refer to the manufacturer's guide for installation instructions. Contract a licensed electrician to install alarms that are wired into the building's electrical system. Test the fire alarms.


All measurements, methods and standards for fireproofing materials and installations can be found in the National Building Code. Encasing steel in concrete, which acts as natural insulation, can help disperse heat away from the support beams.


Always wear the appropriate personal protective equipment, such as safety glasses and steel-toed boots, when installing fireproofing systems, to reduce the risk of injury. Only use fireproofing products and materials that have been properly tested and certified by the regulatory body in your area.

Things You'll Need

  • Concrete
  • Form boards
  • Steel rebars
  • Metal mesh
  • Intumescent paint
  • Fire alarms
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About the Author

David Hill began writing professionally in 2008. He has written for communities at Seneca College, where he studied the art fundamentals. Hill also studied art fundamentals at Sheridan College.