Fireplace and Chimney (Leaving Cert Construction Studies): Revision Notes

Fireplace and Chimney

• Fireplaces have been a central feature of homes for centuries, valued for both their aesthetic and functional qualities.
• They can be traditional or modern in design, but all require a chimney to remove smoke and gases from the building.
• Chimneys can be placed internally (within external, partition, or party walls) or externally (freestanding or with an external flue).

Functions of a Fireplace

1. Generate Heat Safely

• Built from non-combustible materials such as ceramics or concrete, which can withstand high temperatures.
• Well-insulated at the back to reflect heat into the room instead of losing it through walls.

1. Extract Smoke and Gases

• The chimney uses draught (created by flue height and air pressure differences) to pull smoke and gases upward.
• Flue must be the correct width — too wide and draught will weaken, reducing efficiency.

1. Burn Fuel Efficiently

• A well-designed grate allows air to circulate under the fuel, enabling hotter, cleaner burns.
• Open fires can lose up to 80% of their heat because of the open design.

Heat Loss

• Heat escapes up the chimney along the same route as smoke.
• Only around 25% of the heat from an open fire reaches the room.
• Additional loss depends on insulation quality.

Chimney Placement Options

• External wall – Built into an outside wall.
• Partition wall – Between rooms, not an external wall.
• Party wall – Shared wall between adjoining houses.
• Freestanding – Independent of the house walls.
• External flue – Metal or other external flue pipe attached outside the building.