- Mt Lebanon Magazine - http://lebomag.com -

fireplace and wood stove safety

Even if you don’t have a fireplace or a wood stove, sometimes just picking up the scent of wood smoke as you’re outside on a chilly fall day can seem like a promise of a warm cozy night ahead. Just remember to use some caution when you’re tending the fire. Here are some tips from the Mt. Lebanon Inspection Office for safely enjoying this cold-weather ritual.

Only burn regular split hardwood, such as maple, beech, ash, hickory or oak. Never use painted wood, paneling, plywood or any other wood product used for construction or recreation. They generally have glues or plastics that will create a fire that burns hotter and emits more toxic fumes than regular hardwood.

Fire wood should be cut, split and air-dried for at least a year. Well-seasoned hardwood will show cracks at the ends of the logs. Keep the wood sheltered from the elements.

WOOD BURNING STOVE INSTALLATION
Make sure you follow the manufacturer’s instructions. All wood stoves require specific minimum distances or clearance between the stove and all combustible materials. Insufficient clearance could cause heat from the stove to penetrate small openings and ignite nearby combustibles. If you can’t find the manufacturer’s information—which, come on, man, everything’s online now but if you can’t, then look to the building code for clearances. When in doubt, contact the inspection office, 412-343-3408, or the fire department, 412-343-3402.

Most of the clearance problems come from roof penetration, where the installer does not cut enough of the roof decking away, or tries to seal the opening with asphalt shingles and roof cement, both of which are flammable. You can reduce the amount of clearance needed by installing a heat shield.

CHIMNEY OR FLUE PIPE
The chimney for a wood stove must be masonry or Underwriter Labs listed, and factory built. Never, under any circumstances, should an unlined, single-brick chimney be used for a wood stove. Single-brick chimneys are prone to deterioration, which may allow potentially dangerous situations to develop. Hot gases can ignite combustible material through the smallest openings. Many older homes have unlined chimneys made of double brick, or a clay flue liner. You can use these for a wood stove if you check carefully for cracked mortar, loose or missing brick, or a broken section of the liner. Unless the chimney is absolutely straight, the individual flue sections may not be able to provide adequate protection, because the flue sections may not be able to lock completely into each other. Exterior discoloration of woodstoves’ metal chimneys indicate a possible breakdown of the insulating material. Questionable sections should be replaced.

VENTILATION
Venting the stove  is the most important part of a wood-burning system. About 90 percent of stove-related fires originate within the venting system. A venting system is not a chimney. It consists of lengths of 24-gauge or heavier stovepipe, which connects the stove to an approved chimney. The vent must be as short as possible, with no more than two right-angle elbows. The sections of stovepipe should be assembled with crimped, male ends of the sections facing down, toward the stove. Stovepipe sections should be fastened with at least three sheet-metal screws or other fasteners. Seams must overlap and face up on inclined runs.

Stovepipe clearance is extremely important. The pipe must never pass through an interior wall, wall, floor or ceiling. Stovepipe should never be used for a chimney, because the elements will rust. Wherever possible, the stovepipe should go directly into a lined masonry or Underwriters Labs-listed, factory-built chimney. If your stovepipe must pass through an exterior wall to reach the chimney, maintain an 18-inch minimum clearance to all combustibles. Consult the inspection office for direction on the proper connections or metal thimbles designed for that purpose.

OPERATIONS AND MAINTENANCE
Clean your stovepipe and chimney with a wire brush at least once a year. Use a reputable chimney sweep to clean the chimney or flue pipe.

Avoid creosote buildup. Creosote is a highly combustible fuel that burns intensely. A slow-burning fire in a modern, damped-down, airtight stove produces a flue temperature in the 100 to 200-degree range. These comparatively low temperatures do not sufficiently carry all of the unburned, combustible gases into the atmosphere. Instead, they condense along the walls of the stovepipe and the chimney as creosote.

Creosote takes three forms:

TIPS FOR BUILDING A FIRE