About Fireplace and Chimney Construction

A chimney vents hot gases and smoke from a fireplace to the outside environment. It is typically vertical, which ensures the gases flow more smoothly. A fireplace is any structure that contains a fire. The purpose of the fire is usually for heating, although it can also be used for cooking.

A chimney is typically constructed of clay bricks due to their high heat tolerance. Bricks are less able to tolerate transverse loads, meaning that it is easily to shift them sideways. This means that the fireplace on each floor of a building should typically share the same chimney to reduce the possibility of the chimney collapsing.

Homeowners today typically use fireplaces as a supplemental source of heat rather than the primary source of heat. The placement of a chimney in modern houses is therefore less critical than it was in older designs. Fireplaces typically use a vent pipe to conduct flue gas from the fireplace to the chimney. This design allows the fireplace to be separated from the chimney, since the vent pipe can go around obstacles. Some heating appliances do not even use a chimney and run the vent pipe directly through an outside wall.

Masonry and manufactured fireplaces are the most common types of fireplaces. A masonry fireplace is constructed of brick or stone. A manufactured, or prefabricated, fireplace is essentially a box constructed of sheet metal. Both types of fireplaces can use a variety of fuels such as wood, propane and natural gas.

A ventless fireplace can use liquid propane or a flammable gel. These types of fireplaces do not require vents because the fuel burns with almost 100 percent efficiency, meaning that these fuels produce very little gas when they burn. The primary design consideration for ventless fireplaces is that they must be appropriately sized for the room. Ventless fireplaces also require carbon monoxide sensors.