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Air Vent

An air vent is a means of supplying fresh air to a room in your house from outside which helps with the burn of the fire. Normally only required on higher input gs engines or higher output solid fuel stoves.

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Balanced Flue

See Flue Types.

Builder’s Opening

A builder’s opening is the whole at the bottom of the chimney. When a fireplace is removed, the opening is usually expanded to the builders opening for installing a stove.

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Class 1 Flue

See Flue Types.

Class 2 Flue

See Flue Types.

Constructional Hearths

A constructional hearth is the area in front of the fire that protects the wooden floor beneath, if your fireplace does not have a hearth and you wish to install a solid fuel burner then you must a have a hearth installed.

The constructional hearth is used to stop joists beneath the fire totally drying out and becoming a fire hazard, if any of the fire embers were to find there way to joists underneath your fire there would be a danger of them catching fire. Hearths must be made from fire retardant materials and be in front of the fire by at least 18 inches, 6 inches deep and 48 inches around.

Inset Fuel-Effect Fires or Convector

This type of gas fire uses a heat exchanger to recover heat that would normally be expelled up the chimney back into the room where it is installed. This type of fire is usually more efficient which results in lower running costs with a higher heat output than a standard radiant fire.

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Decorative Gas Fires (DGF)

This type of fire usually simulate a real solid fuel fire and hold ceramic coals, pebbles or logs. These fires have a low heat output and are used for their aesthetics or heat production.

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Fire Back

Also known as a Clay Back, it is the back wall of the fire which protects the structure of the building and helps to reflect the heat back into the room where the fire sits.

Fire Surround

The fire surround incorporates the mantelpiece and the protective sides of the fire opening.

Fanned Flue

See Flue Types.

Fire Bed

The fire bed is the area where the solid fuel sit or the part of the gas fire where the ceramic material sits and above the gas burner.


This is a protective screen which protects the room from any embers falling out of a real soid fuel fire and also protects anyone from injuring themselves on any type of fire.

Flame Supervision Device

If the fires pilot light is for some reason extinguished then this device will cut the gas supply as a safety precaution.

Flue Lining

A flue liner is a flexible metal tube which stretches the length of the flue, theses are installed when the flue is old and not in good condition to prevent any leakage of smoke and toxic gasses from the fire below. There are generally 3 types; Gas ( for gas fires), 316 for Wood burning stoves and 904 for coal, coke, etc.

Flue Terminal

This is a like a vented cap which sits onto of the chimney, these are not required by any regulation but we would recommend installing a rain / bird guard to prevent birds sitting, nesting or falling down the chimney and becoming stuck. A guard also helps prevent soot falling down the flue when it rains.

Flueless or Catalytic Gas Fires

This type of fire does not require the house to have a chimney, flue or wall vent as the toxic carbon monoxide that is produced by the fire passes through a catalytic converter. The only by-products are water vapour and carbon dioxide which can easily be dispersed with adequate ventilation.


A fret is an external decorative fire front, this is usually freestanding and finished in brass, silver or black, it is also possible to buy these from some manufacturers in a range of colours and styles. Inset fires use the Fret to conceal the controls for the fire.

Fuel bed

This is the simulated fuels that sit inside a gas fire to dissipate the flame, they are often made to look like wood, coal or pebbles.

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Gel Fires

This type of fire burns an alcohol gel and does not require a flue or chimney.

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Gas Input

This is measured in Kilowatts per hour or kWh, this will be displayed by the manufacture as minimum and maximum settings.

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The hearth is the protective slab that sits underneath the fire/stove to ensure no heated elements stray onto the floor. Also see Constructional Hearths.

Heat Output

This is the maximum amount of heat that a fire produces which is measured in Kilowatts per hour.

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Inset Fire

An inset fire sits within the fireplace opening and is flush with the surrounding wall. These fires are made to fit into existing fireplaces, these fires usually have a flame effect to give the appearance of a real fire.

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Low Lintel

Some inset fires are designed to fit into fireplaces where the lintel is lower than a regular fireplace.


Liquid Petroleum Gas is used where it is not possible to have a mains supply, such as rural properties. the gas is supplied via tanker to the house where it is stored in a large storage tank on the property or can be supplied in bottles. Not all fires will work with LPG and some may need to have converter kits installed or in some cases a bespoke fire will have to be made by the manufacturer.

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No-Vent (NV)

Most 16 inch inset fires will normally be NV fires, these fires do not need extra ventilation installed.

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Outset Fire

These fires will sit outside the fireplace opening or is able to be wall mounted and are not restricted by the size of the fireplace opening.

Oxygen Depletion Sensor (ODS)

The ODS is a safety device which will extinguish the fire should the toxic gases build up to a dangerous level, this is fitted to all pilot assemblies.

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Permanent Pilot

A permanent pilot light is always lit which means that the pilot light does not need to be lit every time the fire is turned on.

Piezzo Ignition

This type of ignition can be found on most types of gas fire, it allows the operator to turn a knob which fires a spark, this knob or button is normally concealed behind a cover.


The pilot is a small gas flame which is used to ignite the main fire flame.

Power flue

See Flue Types.

Pre-Cast Flue

See Flue Types.

Pre-Fabricated Flue

See Flue Types.

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Radiant Gas Fires

All gas fires and solid fuel fire give out radiant heat, in this process heat moves through the air away from the fire. Hotbox is sometimes the name given to inset fires.

Rear Vent

A rear vent is where a power flue will connect to the fire and pass through the outside wall, these are also used for balanced flues.


The fireplace rebate is the measurement between inside and outside leg return, the leg return is the distance between the front of the back panel to the wall behind. This can be altered to between one and three inches.

Remote Control

Controlling the operation of a gas or electric fire by a remote device. This type of control is ideal for those who want the added luxury of being able to adjust their fire from the comfort of their chair. On most gas fires, this type of control will be available only as an extra cost option – although more and more electric fires are now being produced with remote control as standard.

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Slide Control

A slide control is the lever which slides up and down and controls both the heat control and the on and off function of the fire. This control is normally positioned at the to of the fire unit or near the top.

Spacer kit

These are mainly used with electric fires where it is necessary to alter the depth of the fire place opening.

Standard Fireplace Opening

This is the hole in the fireplace where the gas, electric or solid fuel fire will be installed, the standard size of this opening is sixteen inches x twenty two inches. (420mm x 570mm) Adjustments may need to be made to ensure that your new fire fits securely.

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The trim is the decorative strip that runs around the outside of the fire, they normally are supplies in brass or metal but can be supplied in a variety of colours and styles if required.

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If a gas fire has a seven kilowatt or less input the ventilation is not normally required but and fire over this will usually require some form of extra ventilation. A certified gas fitter will be able to advise you of if this is necessary and advise you how to go about this task. If a solid fuel appliance emits an output higher than 5kW, then additional ventilation is usually required.

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