Chimney, structure designed to carry off smoke from your fireplace or furnace. A chimney also induces and keeps a draft that provides air for the fire.In western Europe prior to 12th century, heating fires were almost invariably placed in the midst of a place, and chimneys were therefore rare. Most from the characteristic varieties of modern chimneys originated in northern Europe, when masonry techniques were developed that allowed the building of a hearth along a wall with a fireproof backstop and flue. Some medieval chimney stacks were tubular, plus some had ingenious conical caps with hooded side vents to shield against rain. During the 15th and 16th centuries, tall chimneys elaborately decorated with carvings, niches, and inlays formed a significant part of the architectural ensemble. As housing grew more commodious and several rooms in a dwelling were furnished with fireplaces, flues were grouped to handle smoke to some central chimney of masonry. In English housing of the time, each flue emerging with the roof line was treated being a separate columnar structure with base, cap, and polygonal shaft, generally of elaborately shaped bricks. Chimneys of the 17th and 18th centuries tended to be rectangular also to have projecting top courses that formed protective caps. In North America a massive chimney with this type became the central feature with the colonial New England farmhouse. As coal was introduced for domestic heating, chimney construction took over as the subject of serious study, as well as in the late 1700s Sir Benjamin Thompson established the definitive forms and proper relationships with the chimney’s essential parts.An ordinary domestic chimney includes three parts: the throat, the smoke chamber, as well as the flue. The throat is the opening immediately higher than the fire; it usually narrows to your few inches in width just beneath the damper, a door which can be closed if the furnace or fireplace just isn't used. Above the damper may be the smoke chamber. At the bottom of the smoke chamber is a smoke shelf formed by setting back the masonry on the top in the throat on the line in the back wall from the flue; its function is always to deflect downdrafts that may otherwise blow smoke out in to the room. The smoke chamber narrows uniformly toward the most notable; it decelerates drafts and acts as being a reservoir for smoke held in the chimney by gusts throughout the chimney top. The flue, the primary length of the chimney, is generally of masonry, often brick, and metal-lined. Vertical flues work most effectively, though a bend is oftentimes included to cut back rain splash; bends can also be necessary when several flues are united in a very common outlet.Industrial chimneys are generally free-standing single flues with cylindrical cores of firebrick and outer jackets of steel, brick, or reinforced concrete, often having an insulating air space between to allow for differential expansion. Because the taller the chimney, better the draft, some industrial chimneys are more than 300 feet (91.5 m) in height.