Glossary Of Terms

AFUE – AFUE stands for “Annual Fuel Utilization Efficiency.” It is the official heat source measurement rating for fireplaces and wall heaters.

Air Inlet – Designed to be the port of entry for combustion air in a wood burning appliance.

Ash – A noncombustible solid material that is a byproduct of solid fuel combustion.

Back Draft – Also known as “back draught,” this is an undesirable effect that occurs when strong winds blow smoke back down the chimney and into the room. Common in poorer houses, today’s chimney designs are able to prevent this from happening.

Baffle – A partition in a wood burning fireplace that directs the flow of gases and heat.

Bellows – An accessory with an expandable bladder that is used to feed air to the flames of a fire in a wood burning stove.

Burn Rate – The combustion rate of a material. Generally, it is expressed in pounds of fuel consumed per hour.

Carbon Dioxide – Also referred to as CO2, this gas is produced with complete combustion of carbon units. In large amounts, it can be dangerous, but the amounts produced by normal units are small quantities.

Carbon Monoxide – One of the most dangerous gases produced in combustion, CO occurs when incomplete combustion of carbon takes place. Colorless and odorless, carbon monoxide can be deadly if there is not good ventilation.

Chimney – A part of the venting system that allows flue gasses to pass to the outdoors.

Combustible Materials – These materials are made of or surfaced with wood, compressed paper, and other fibers that will ignite and burn.

Combustion – The process of burning that results in both heat and light.

Companion Set – A set of fireside tools used to manipulate the coals and logs inside a fireplace. Traditionally, the set sits next to the fireplace and consists of a poker, shovel, brush, and coal tongs.

Damper – A device that consists of a movable plate that directs the flow of air and gases. It is used to close off a flue or chimney when not in use or to allow air in when the fire is going.

Electronic Sniffer – A small device that is able to detect the presence of small amounts of certain gases. Used in gas supply lines and for appliance leak detection, the device will emit a loud, piercing noise if it detects any dangerous gasses.

Firebox – here the fuel is located and where primary combustion occurs in a solid fuel appliance.

Firestop – A barrier put in place to span the air space between the outer walls of the chimney and the combustibles. The job of this piece is to prevent the spread of fire between floors of a structure.

Flue – The venting or chimney that connects the fireplace with the outside, allowing the passage of gasses.

Grate – The metal frame used to hold the fuel inside a fireplace.

Hearth – The thick slab on the floor where the fireplace is mounted.

Ignition Temperature – The lowest temperature needed for combustion to occur.

Insert –An appliance, either gas or wood, that retrofits into an existing wood burning fireplace.  Inserts are designed to burn fuel more efficiently and transfer heat into the house more readily than traditional fireplaces.  Often inserts are used when the homeowner wants increased heat and efficiency performance but doesn’t want to completely redo the current fireplace.

Kindling – Material that is easily ignited and used to start a fire. Usually this includes thin, dry pieces of wood, cardboard, or newspaper. There are also manufactured products available on the market today.

Main Gas Burner – The device that is responsible for the final conveyance of gas into the combustion zone. The device consists of multiple components: the burner orifice, air shutter, mixer, and burner head.

Mantel – The decorative facing surrounding the fireplace, usually including a shelf.

Negative Air Pressure – A situation that occurs in tightly constructed homes during which the air pressure inside the home is lower than the outdoor ambient air pressure.  Negative pressure can make it difficult to make a conventional wood burning fireplace operate and will often result in smoke and exhaust coming into the house rather than exiting through the chimney.  High efficient gas fireplaces do not usually suffer performance problems from negative pressure issues in homes.