Keeping the Fire in the Fireplace

Forget the rooftop dancing. Keeping a chimney clean is serious work.

There are 26,000 residential chimney fires each year, according to the National Fire Protection Association. At the very least, these fires weaken the chimney structure, making it more vulnerable in another fire. At worst, they can burn a house down.

The good news is that you can prevent chimney fires with regular inspection and cleaning.

The chimney is the one part of a house not protected by the roof. It's subject to rain, wind, lightning and animals, all of which can interfere with its main job -- letting out smoke and other byproducts of burning fuel.

And remember, whether you heat with gas, oil or solid fuel, the furnace or wood stove is vented through your chimney. Those appliances can also produce byproducts that lead to chimney fires.

From the Bottom Up

The fireplace and chimney have a number of parts, all of which need attention.

The firebox is where you put the wood and build the fire. The damper is the part that controls the airflow up the chimney.

Behind the damper is a smoke shelf, designed to prevent back drafts and to catch any rain that comes down the chimney.

Above that is the smoke chamber, which is usually two to four feet high and funnels the smoke into the flue.

The flue is the vertical passageway inside the chimney. There are separate flues for each heating appliance, so one chimney can have several flues. For example, your gas furnace and wood stove or fireplace usually share a chimney.

A liner is a vertical shaft, usually made of terra cotta or stainless steel and surrounded by insulation, which directs smoke upward efficiently. Liners are specific to the size of the chimney.

Smoke goes up in a spiral, so round liners work better than oval and oval ones work better than square, said Steve Crowell of Winston's Chimney Restoration and Service in Kensington.