Why, with all the truly flammable materials found in a typical home, is the safety of the one wood-based construction product that is always manufactured to be fire retardant so frequently questioned? Possibly it is because the makers of other products find it extremely difficult to compete with cellulose on any other basis. Cellulose is simply better insulation, and, as more and more tests are demonstrating, it's safer insulation, too.
Ever since cellulose insulation was first marketed in the 1920s sellers of competing products have raised questions about the safety of the material. These questions are based on legitimate concerns. Cellulose insulation is an organic material. (It’s made from recycled paper pulp.) Without special processing organic materials will burn.
Of course, if organic materials are automatically assumed to be fire hazards, most building materials used in the United States are hazardous, and most residential and commercial buildings are dangerous structures.
Cellulose insulation is one of the few wood based building materials that is always treated for fire retardancy and is covered by industry and government standards. Wood framing members, wood floor and roof underlayment, wood siding, wood casegoods, and many other common wood items are not usually treated for fire resistance.
Petroleum-based materials in siding, roofing, ducts, flooring, floor coverings, wall coverings, and upholstery are not usually fire resistant. Why, with all the truly flammable materials found in a typical home, is the safety of the one construction product that is always manufactured to be fire resistant so frequently questioned? Possibly it's because other products find it difficult to compete with cellulose insulation on any other basis. Cellulose is simply better insulation. Early investigations
The Fire Hazard Case Against Cellulose Insulation is based on a few surveys that apparently found a high incidence of non-compliance with government and industry standards in samples of cellulose insulation taken from homes. These studies were done by the U.S. Consumer Products Safety Commission in the late 1970s, and more recently by the California Bureau of Home Furnishings and by the CertainTeed Corporation, a maker of glass fiber insulation.
None of the studies have had rigorous scientific review and independent confirmation, but they do merit careful assessment. The CPSC is one organization that has made such an assessment.
Because of its findings CPSC kept close watch on the cellulose insulation issue. As more and more experience accumulated it became apparent there was no significant increase in the number of so-called “insulationrelated fires” involving cellulose.
In the fall of 1985 CPSC requested Congress to repeal the federal cellulose flammability standard. Representatives of the Commission testified that the “cellulose flammability standard was not necessary to assure the safety of cellulose insulation and should be repealed by the Congress.”
While CPSC was arriving at this conclusion David T. Darby, assistant chief with the Oklahoma City Fire Department, became concerned about the “cellulose hazard" after noticing an increase in the number of attic fires associated with home weatherization programs.
To his surprise a study of “insulationrelated fires” revealed that such fires involved mineral fiber insulation and cellulose at rates that paralleled the market shares of the materials. Cellulose, turned out to be no more hazardous than mineral fiber insulation! He looked farther and found there was a common factor in virtually all “insulation-related fires” — recessed lighting. The hazard arbitrarily attributed to cellulose insulation was equally applicable to all insulation.
These findings have been confirmed in other states. In California, where another study apparently revealed a high incidence of nonconforming cellulose insulation, a state task force studied over 2 million house fires and reported:
- There does not appear to be a significant number of fires related to any particular manufacturer’s product, and
- Heat-producing devices and electrical short circuits were major factors in insulated-related fires.
Even when a fire is classified as “insulation-related,” the insulation is seldom the first material to ignite. In the vast majority of cases a heat-producing device, such as a recessed lighting fixture, is covered by insulation. Heat builds up and is conducted through wiring or metal brackets to a wood structural member. The wood, or electrical insulation, usually ignites first. Exploiting fear
The makers of mineral fiber insulation represent fire as a “given” hazard of cellulose insulation, in spite of the vast amount of contradictory data. In 1980 the Mineral Insulation Manufacturers Association, now known as the North American Insulation Manufacturers Association, published a “technical bulletin” based on the original CPSC study. Additional NAIMA publications with distorted fire hazard claims have appeared at regular intervals since then.