Although no practical building material can be considered fireproof, utilizing fire-resistant materials and assemblies helps reduce damage from fires. It can also improve safety standards and help structures return to use faster, boosting community resilience.
Natural materials like lumber offer little in the way of fire resistance, but builders have access to specialized chemical treatments that can significantly increase their performance.
Combustible Materials
Choosing materials for your building project can be confusing if you don’t understand the differences between combustible, non-combustible, ignition resistant and fire-resistant materials. They may sound similar but they are different, and have a lot to do with how well your home or commercial structure will perform in the event of a fire.
Non-combustible materials are those that will not burn, even when subjected to a high heat. Typically they also will not contribute to the spread of fire within or outside a building and won’t release much smoke. These are the ideal materials to use in construction if you are in a wildfire zone or any other area where a fire is a possible hazard.
There are different methods for evaluating a material’s flammability and the flame spread rating of various materials is one way that is used to determine this. The flame spread index (F) of a material is based on the speed at which it will burn and the rate of the flame front as it travels over the surface of the material. A higher F means a faster burning material and a lower F indicates a slower burning material. Usually there are different F ratings for a material based on its composition and thickness. For example, a steel sandwich panel with mineral wool filling and glue and a polymer coating will have an A1 F rating while a Ruukki sandwich panel with PIR foam filling and glue and a Polyurethane or polyethylene coating would have an A2 F rating.
Ignition Resistant, or Flame Retardant are chemical or treatment applied to a combustible material that makes it less likely to burn or ignite. It is common to use these on textiles like curtains and upholstered furniture or on synthetic based materials such as plastics, foams or certain fabrics. They are also commonly used on natural based materials like wood, paper or cotton as well.
The term “fireproof” has been used to describe the ability of a material to withstand fire but this is inaccurate because a structure can only be made from non-combustible materials or by using a combination of fire-resistant materials that together have a high enough performance rating for a specific time period (i.e., 20-minute, one-hour or two-hour walls).
Type iii construction is the least fire resistant of all building types and allows for the use of combustible materials like wood framing and siding. This type of construction is commonly used in residential buildings and low-rise commercial structures but it must be built to fire protection standards to ensure a safe environment for occupants in the event of a fire.