Glossary of Fireplace Terms

AFUE - Annual Fuel Utilization Efficiency. An official heat source measurement rating for fireplaces and wall heaters.

ANDIRONS Free standing metal supports, usually constructed of cast iron or steel, for firewood on a hearth. Each consists of a horizontal bar supported on short legs. May include decorative fronts.

ANSI The American National Standards Institute. An organization which lays down acceptable standards and testing parameters for such things as gas fires, etc - largely related to safety matters.

Arched Insert More properly, an 'arched insert fireplace'. So called because of the distinctive arch in its design. Very popular in Victorian times, and almost always found in bedrooms of the period. Usually it is a cast iron unit set into a fire surround. They may be used for burning solid fuels like coal, coke or wood or have gas logs, gas coals or electric fires inset.

Back Draft More properly 'back draught'. The effect where in strong winds, smoke could be blown back down the chimney into the room - very undesirable, but very common in poorer houses. The term also has a slightly wider meaning referring to any fire or flue emission which flow contrary to the desired or intended direction - therefore extensively used in firefighting. Nowadays, various cowls, rotating vents and other chimney-top devices are available to prevent this effect on domestic chimneys.

Baking Soda Bicarbonate of soda, usable as an emergency fire extinguisher. When poured on a blaze baking soda releases carbon dioxide, which will not support combustion.

Basket Or fire basket. An alternative type of fire arrangement whereby a free-standing metal basket in which fuel is placed in an open fireplace. Fire baskets may also be fitted with gas coals or gas logs or electric fires.

Bituminous Coal A solid fuel suitable for burning in fireplaces. It gives off more heat than hardwood. A special "coal basket" is required for its use.


BTU - British Thermal Unit, the primary heat measurement unit used by the hearth industry. It is the amount of energy required to raise the temperature of 1 lb. of water by 1 degree F.Despite its name, the unit is used universally in North America and only sometimes in Britain.

Carbon Dioxide - Sometimes referred to as CO2. Carbon dioxide is a gas that is produced with complete combustion of carbon units. It is not generally dangerous in the amounts produced.Though it is colourless and odourless and is present in small quantities naturally in air, it is dangerous if inhaled in large amounts.

Carbon Monoxide Sometimes referred to as CO and probably the most dangerous gas produced in combustion. Usually, it occurs when incomplete combustion of carbon takes place. It is colourless, odourless, and deadly even in relatively small quantities if there is not good ventilation.

Catalytic Combustor - A device used in some wood burning stoves to increase combustion efficiency by lowering flue gas ignition temperatures.

Ceramic Fibre Log Set. In the past log sets were made from concrete and looked false. Today the better log sets are made from a Ceramic Fibre that can look like wood. When the flame touches the ember material and side of the log, it glows like a real fire.

CFM, Cubic Feet per Minute. This is the amount of air that a blower will move. There is no magic figure that is suited to all units. A blower should be tapered to a particular unit. If the amount of air movement is not balanced to the size of the unit it can become noisy.

Chinaman's Hat A conical device fixed to the top of a chimney to prevent rain or other debris falling in and obstructing the flue. So called because of its resemblance to the traditional headgear worn by peasants in China.

Chimneypiece or Chimney Piece Also known as a 'Hob' and sometimes a 'Horseshoe' because of its distinct horseshoe shaped arch. Rarely seen nowadays, the original Victorian chimneypieces were practical solid fuel units, usually coal fuelled, with side oven boxes and trivet for boiling kettles or stewpots for hob cooking. Nowadays they are generally purely decorative.

Class 'A' Flue An insulated double or triple wall pipe approved for use with any fuel.

Clearance - The distance required by building and fire codes between a portion of the fireplace unit, including pipes and chimney, and combustible materials.Zero clearance refers to no clearance between such surfaces.

Chase - A decorative surrounding that covers the metal flue inside the chimney.

Chimney Breast The area extending from above the fire chamber opening to the ceiling. It may include a mantle shelf, decorative facing, or be plain flat wall surface

Chimney Cap - A vented cap placed on top of a chimney to prevent obstructions such as leaves and bird nests. A chimney cap can also protect the chimney top from gusts of wind that will interfere with the draft.

Chimney Pot - A decorative pot set at the top of a chimney that can extend the chimney's length and improve its draft.

Companion Set Sometimes referred to simply as 'Companions', they are a set of fireside tools traditionally found standing on the hearth for use with solid fuels like coal or logs. Conventionally, a Companion Set would consist of a poker, shovel, brush and coal tongs, suspended on a central stand - available in black, brass, copper, pewter, antique and chrome finishes.

Combination Fireplace Sometimes known simply as 'Combinations'. Simply, an all-in-one fireplace, usually in cast iron with a top mantel shelf. May have side tiled panels or not and generally with an arch shaped chamber opening.

Convection Air. Is the cold room air that passes through the stoves heat exchanger, is heated and put back into the room.


Damper A trap door like device used to close off a flue or chimney when not in use and to allow air in when a fire is going. Most dampers are installed at the base of the flue and are reachable from within the firebox.



Draft The flow of air through a heating system. Air from outside is drawn naturally under the fire, through it, and up the chimney - this is usually how smoke and gases are channelled outside thus preventing backdrafts which blow smoke back into the room.

Draw A well designed and functioning fireplace has what is referred to as good draw - the smoke is pulled up into the chimney and air is circulated in the firebox for good combustion. A fireplace with poor draw sends smoke back into the room and provides low efficiency.

Emissions – Unburned gases and particles as a result of incomplete combustion.


Fender A frame, usually in black iron or more commonly in polished brass, placed around the front of a hearth and around it to protect from scuffing, as a barrier to prevent hot coals falling onto carpets or as a purely decorative feature.


Fire Bed The actual bottom grate or bars on which solid fuels like coal or coke are placed. These are usually metal slats or bars which allow draft to pass through from beneath and so aid combustion of the fire.


Firestop - A noncombustible device that seals openings between floors to prevent smoke or fire from penetrating from one level to the next.

Firebox The interior portion of the fireplace where the fire is built. Sometimes referred to as the fire 'Chamber'.

Flue - Any vent or chimney that connects a combustion device with the outside, the passageway in a chimney for conveying gases to the outdoors.

Flue Collar - Ring on an appliance for attaching a draft hood, vent connector, or other venting system. The flue collar determines the size of the vent

Free standing Stove. This is a stove that sits on a pedestal and is independent of any fireplace.

Fret A fret, or fire front is a decorative front cover for a fire unit. It is usually free-standing and not fixed and may be removed to access the ash pan beneath the firebox or chamber for emptying or cleaning.

Fireplace Insert. This is a unit that is installed into a masonry or factory built wood burning fireplace with a chimney.


Gas Logs – an open flame appliance with manufactured ceramic or ceramic fiber logs placed over a burner to provide dramatic realism of a traditional flame. Manufactured log sets have a burner that uses either natural gas or propane.

Gas Fireplace. This is a unit that can be put into new construction or renovation without an existing chimney.

Grate – a metal frame used to hold and contain burning fuel in a fireplace.. Sometimes referred to as the 'Fuel Bed'.

Hardwood Wood from deciduous trees (those that lose their leaves in the fall). Harder to ignite and often more difficult to split, hardwoods give off more heat than softwood.

Hearth Usually a thick slab on the floor on which the fireplace is mounted. But it is also sometimes used as general term to describe the whole hearth slab and fireplace setting. Generally, hearths fall into 2 categories: a slab of stone such as granite or slate, or sometimes a tiled concrete slab. Its function was originally to protect the wooden floor from overheating or catching fire - an ever-present danger in olden days.

Heat Exchanger. This device is responsible for transferring the heat created in the firebox to the convection air and into the room. The points to look for in an efficient heat exchanger are 1) a large surface area to allow the convection air sufficient contact to transfer as much heat as possible from the fire to the room. 2) The heat exchanger should have natural convection allowing the air to circulate freely with or without a blower. 3) It should be of solid construction to allow for durability and good heat transfer qualities.

Heat Plate A metal plate, usually made of steel, fitted to the hearth slab to protect tiles or stone from cracking or crazing due to intense heat generated by some solid fuels.


Hood Also known as a 'canopy'. Somewhat self-explanatory. Some cast iron fireplaces had a canopy above the firebox aperture, initially to catch any escaping smoke and direct it up the Chimney, thus helping prevent back drafts. Nowadays they are purely decorative and some fireplaces have them included as standard. Hoods can also be purchased as separate items and fixed to a unit if required.

Hopper A container for a fuel source such as wood pellets or coal that is attached to an appliance so that the fuel is fed to the burner.


H.P.B.A.C. The Hearth, Patio and Barbecue Association of Canada (HPBAC) is a trade association, dedicated to serving the needs of our members, established for the purpose of: providing a voice for the industry, promoting and protecting the interests of those engaged in the hearth, patio and barbecue industries, coordinating and integrating the needs of industry dealers, distributors, manufacturers and suppliers, providing educational and networking opportunities to all our members on both national and regional levels, promoting consumer awareness of the benefits associated with our products.

Insert - A fireplace insert retrofits an existing fireplace to allow it to burn a different fuel or to make it more efficient at burning fuel or producing useable heat


Kindling - Easily ignited material used to start a fire. Traditionally, kindling is thin, dry wood, but newspaper or other manufacture products are often used.

Liquid Propane - liquefied petroleum gas, available in cylinders, for home use. LPG Liquefied Petroleum Gas, (sometimes 'Liquefied Propane Gas'), or bottled gas sold often under the proprietary names of 'Propane' or 'Butane', also called LPG, LP Gas, or Autogas. This is a mixture of hydrocarbon gases used as a fuel in heating appliances and vehicles. Typically LPG is most common where no gas pipeline is in place and in remote settings where gas cylinders are used or preferred.

Mantel - an ornamental facing surrounding the fireplace or simply a shelf above a fireplace.

Metal Liner - A liner placed inside an existing chimney to reduce the flue diameter and increase the speed at which smoke exits. Usually used with fireplace inserts but also used when an existing chimney is unlimited or deteriorating. Metal Liner - used primarily with fireplace inserts and placed inside an existing chimney (usually masonry) to reduce the diameter of the flue for more rapid exit of smoke and combustion gases. Also used when an existing chimney is unlimited or deteriorating. Flue Liner simply called a 'metal liner'. This is a tubular liner placed inside an existing chimney to reduce the flue diameter and increase the speed at which smoke exits. Generally recommended for use with gas fires, but always in older buildings where the fabric of the chimney may have deteriorated or become partially clogged with soot or otherwise obstructed. The flue liner provides a smooth, clean, and unobstructed passage for combusted gases and smoke to be expelled from the fireplace. May also be made of concrete.

Natural Draft (B-Vent) Appliance - An appliance that takes in combustion air from the outside and vents the products of combustion back to the outside. Natural draft (B-vent) Appliances - a gas-burning appliance that takes in combustion air from the home and vents byproducts of combustion outside the home. • BV or B Vent. This type of unit takes its air for combustion from the house and vents through a flue. The advantages are that B Vent units and the venting are generally less expensive. It is not recommended that you put a B Vent unit into new energy efficient construction or tightly sealed houses, due to possible combustion problems.

Natural Gas - Colourless, odourless, clean-burning fossil fuel consisting mainly of methane. This is the gas that is piped into most homes.

Pellets - Fuel source made of 100% compressed, recycled sawdust. Pellets are an efficient, clean burning energy source with only 5 to 10% moisture.

Peninsula Fireplace - a fireplace that has three sides of glass.

Pilot - A small, continuously burning flame that a gas appliance uses to ignite the main burner.

Propane - Liquefied petroleum gas containing more heat value than natural gas. Propane is available in cylinders for use in the home. It is colourless, odourless, and non-toxic. (See also: Natural Gas) • LP. (Liquified Petroleum Gas) Propane

Room Heater, Direct Vent Wall Furnace and Wall Furnace. These are industry terms for units that have been designed to a high level of efficiency. You should avoid units that are only decorative rated.

Safety Pilot - A safety shutoff for gas flow that provides a heat source to ignite the main burner.

Seasoned Wood - Fuel wood that has been allowed to dry for at least six months to a year before burning. Seasoned wood has lower moisture content which allows it to burn hotter, more efficiently, and with less smoke.

Spillage - A failure of the venting system that sends flue gases back into the home rather than out the vent or chimney. Combined with incomplete combustion, spillage can result in dangerous levels of carbon monoxide entering the home.

Spill Switch - A device used to detect the occurrence of spillage and alert the homeowner.


Stove. This is a free standing unit that sits on a pedestal and is independent of any fireplace.

Therm - A unit of heat equal to 100,000 British Thermal Units (BTUs).

Vent Free - A device that does not draw outside air to fuel the fire and does not exhaust gases to the outside. An appliance that draws combustion air from inside the home. The appliance is designed to burn so efficiently that it eliminates the need for venting. A vent free device needs to be very efficient to avoid spilling pollutants and toxins into your living room.

Venting - The system of pipes that draws air in from the outside to aid combustion and exhausts smoke and gases to the outside.

Water Column (WC) - A measurement of gas pressure equal to one twenty-eight of a pound per square inch (PSI).


Zero-Clearance Fireplace – Are one type of factory-built fireplace that can be placed safely next to combustible material without risk of fire. These devices typically vent directly to the outside and do not require a chimney. There are very few “Zero Clearance Fireplaces” Most manufactured fireplaces have required clearances. Home owners should check with manufacturers to confirm specifications for individual units.