Fire Resistance

All residential structures contain large amounts of wood. Cellulose insulation is the only wood-based building material that is always treated for fire retardancy. All of our cellulose insulation products are treated with non-toxic minimal amounts of boric acid for fire resistance. By treating the insulation fibers with this natural additive, homeowners can take comfort that this added protection treatment is safe, its less toxic than table salt and is used in eye wash solutions. How does this treatment work? If a fire occurs, the dense structure of cellulose and its fire retardants slow its spread through the home by blocking flames and hot gases and restricting the availability of oxygen in insulated walls and ceilings.


Under CAN/ULC-S703-09, ThermoShield™/ProCell™ cellulose insulation passes tests for fire resistance that include flame spread, smoulder resistance and open-flammability (with tests for resistance permanency).   Our products undergo stringent slow combustion and flame spread ratings tests to meet national and applicable building codes.  During the manufacturing process, our in-house laboratory technician performs daily on-going product testing to ensure the quality and safety of our insulation.

ThermoShield/ProCell will not melt or degrade as most other insulations will when exposed to flame or high temperatures.  Because ThermoShield will only char under direct fire exposure it will provide heat protection longer to adjacent building materials, and therefore allow building occupants more time to escape than would be the case with most other insulation materials.  Tests have shown that our insulation has superior fire containment features than most other commonly used insulations. Because of its fire retardant treatment, ThermoShield/ProCell has the ability to inhibit the spread of fire.  Foam insulation products burn and release large quantities of toxic smoke. Neither conventional insulation nor foam can match the fire ratings achieved with cellulose insulation.  As a fire barrier, cellulose insulation is one of the safest materials in a building.

Tests conducted by independent laboratories shows that Cellulose insulation provides an effective 1 hour fire rating. In several demonstration burns, buildings with cellulose have retained their structural integrity longer than building with other fibrous insulations. In one demonstration the ceiling of a building insulated with fiberglass collapsed 22 minutes after ignition while the cellulose structure stayed in place for 70 minutes. This is an important margin of safety when considering what insulation you choose for your home.

The National Research Council of Canada (NRC) added scientific support to the fire safety benefits of cellulose insulation by testing various fire-testing assemblies and how they perform. This study concluded that fiberglass reduced the fire resistance of insulated assemblies while cellulose insulation improved the fire resistance by 22 to 55%.

Additional testing performed by NRCC tested floor/ceiling assemblies and found that cellulose increased the fire resistance more than twice that of fiberglass in a floor/ceiling assembly.

As a result of this enhanced fire resistance, under some fire conditions, cellulose can provide your family with more time to reach safety and firefighters more time to save your home. View the Big Burn Video to see an actual fire demonstration of the performance of cellulose insulation.