You could have a chimney fire and not know it, according to the Chimney Safety Institute of America (CSIA).

Slow-burning chimney fires don't always exhibit the sights and sounds commonly associated with free-burning chimney fires, which are usually noisy and dramatic events. But a slow-burning chimney fire is potentially more damaging to the chimney and surrounding combustibles than a free-burning fire because they can't vent freely. This lack of ventilation masks the obvious signs of a fire while contributing to rapid heat buildup in the chimney.

Continued use of a damaged masonry chimney system could cause adjacent woodwork and other combustible materials to catch fire. Fallen pieces of damaged clay-tile chimney lining can block the flue and cause harmful gases to back up into a home or furnace system.

Flue gases can also leak into a home where the lining has been broken or damaged.

To prevent any type of chimney fire, the CSIA recommends:

• Using seasoned woods only (dryness is more important than hard wood versus soft wood considerations).
• Building smaller, hotter fires that burn more completely and produce less smoke.
• Never burning cardboard boxes, wrapping paper, trash or Christmas trees.
• Installing stovepipe thermometers to help monitor flue temperatures and adjust burning practices as needed in wood stoves.
• Inspecting and cleaning catalytic combustors on a regular basis, where applicable.

For informational brochures and help finding a qualified chimney sweep in your area, contact the Chimney Safety Institute of America at 8752 Robbins Road, Indianapolis, IN 46268. Phone: (317) 871-2703. Or go to www.csia.org on the Internet.