SAFETY ISSUE: Fireplace & Chimney Maintenance

Incomplete combustion of wood in fireplaces creates a buildup of flammable oils (creosote) in chimney flues, which can contribute to chimney or building fires. Only dry, seasoned wood (preferably hardwood) should be burned in fireplaces. Green and/or water saturated wood burns at a lower temperature and less completely than dry, seasoned wood and poses a greater potential for creosote deposition. Coniferous woods (pine, fir, spruce, etc.) should not be used. They tend to be highly resinous and will deposit more material than hardwoods. Household trash or other items should never be burned in fireplaces.

Artificial logs should only be used in accordance with manufacturers’ instructions and limitations. Most such products are intended to be burned only one at a time. Artificial logs vary in composition from hardwood fibers (sawdust or other sawmill waste) combined with wax or other binders, to petroleum wax (paraffin) mixed with various recycled materials. As a general rule, artificial logs should not be used unless the composition and burning characteristics of a specific product are fully described and deemed acceptable. Plastics, unidentified composites, or other materials of questionable makeup should be avoided.

Fireboxes require occasional cleaning/removal of ashes. Ashes should only be removed when absolutely no embers are present. Because embers can remain undetected long after a fire is out, ashes should only be placed into fireproof, metal containers.

Chimneys should be periodically inspected and cleaned, the frequency of which depends on fireplace use. Annual inspection is recommended for fireplaces that are used regularly. Cleaning may not be necessary at every inspection interval. It should be noted that chemical cleaners (cleaning logs, fire additives, etc.) should not be considered equal to professional cleaning.

Some products incorporate catalytic chemicals that react with the creosote and cause it to soften, flake and debond; however, the dislodged material can accumulate on shelves or other chimney offsets. They also tend to react only with the outer layer of creosote and are only partly effective in the presence of heavy buildups. They also may have no appreciable effect on soot, or residue from artificial logs.

Some products (which employ copper or other metal salts) rely on the rapid expansion of gas created when the salts are burned to dislodge deposited material. The effectiveness of those products is questionable, particularly with respect to heavy accumulations.