In the sign of fire

The fireplace: History

From paleolithic hearths to the flue

The discovery, or rather control, of the fire by early humans during the Lower Paleolithic, a historical period ranging from about 2.5 million to about 120,000 years ago, represents a turning point in human evolution. Indeed, fire made it possible to cook food, thus taking in more protein and carbohydrates and improving nutrition; to be able to work or move around even at night; and to be able to defend themselves from predators. The oldest evidence of early hominid use of fire has been found at several archaeological sites in East Africa.

Thus, it can be argued that the modern fireplace has its origins in Paleolithic hearths via Roman hypocausts to the fireplaces of the early Middle Ages.

It was only toward the end of this period that the fireplace evolved to become a motif of furniture as well: until then the hearth was placed in the center of the room, with a hole in the roof for the smoke to escape. This solution allowed the fire to be kept away from the walls, which were usually made of wood, and spread the heat evenly, however, the dispersion was considerable and certainly the smoke exhaust was not done in the correct way, in fact this configuration of the hearth was the cause of many fires because the roofs were built of thatch or wood, highly flammable materials.

It was the Normans who materialized the idea of building a cape and a “chimney” , necessary to convey the smoke produced by combustion to the upper end of the chimney beyond the roof. Before the spread of this system, fire was generally made to burn inside the dwelling in a special room (such as in theatrium of Roman houses, a word whose etymon comes from the Latin ater: black, blackened). The gradual takeover of new building materials led to the replacement of wooden houses with buildings made of stone and brick. This also changed the arrangement of the fireplace within buildings-thus the modern fireplace, the ancestor of our present-day fireplaces, was born.

The modern fireplace: the origins

Conceived in Nordic countries, therefore, the wall chimney type spread throughout Europe and made its appearance in northern Italy between 1200 and 1300, first in Venice, where there is news of it in 1227, and then in Pisa, where its presence is ascertained in 1298, thanks to the intensification of trade of which the Maritime Republics were the first to take advantage, while in Rome it was introduced in the second half of the 14th century. However, the transition from the central hearth to the wall fireplace continued until the end of the 14th century; in fact, for a long time the use of the central hearth persisted in poorer homes.

The history of the fireplace from 1300 until 1600 is primarily an architectural history and stylistic, as the technical solutions are limited to half embedding the chimney in the wall. They vary in size, which, starting with huge Gothic chimneys, are reduced in Renaissance, Baroque, and Rococo chimneys, certainly bringing efficiency and cost gains. Among the few in this time frame to deal with the fireplace from a technical point of view is Leonardo da Vinci : in his Codex Atlanticus there is a study of feeding the flame by means of a funnel-shaped external air intake, which can improve combustion. This study is the first theorization of the supply of combustion air from outside, which is used to this day in some types of appliances. Leon Battista Alberti in his De re aedificatoria talks about the ideal placement of the chimney in rooms and describes its dimensional characteristics, from the hearth to the dispersion of smoke.

The turning point with the Scientific Revolution of the 1700s.

The real breakthrough in chimney design came as a result of the Scientific and technical revolution at the end of the eighteenth century, a time when the modern sciences flourished: chemistry, physics, geology, biology, economics, etc., and with each the related field of research and practical technique whose great initiators were Volta, Lavoiser, Smith, Spallanzani and others. In our specific case, the revolution came about through the work of two American colonists, who, with a scientific spirit combined with technological discoveries, a keen practical sense and resourcefulness, succeeded in solving virtually all the problems that had hitherto been more or less present in chimneys-Benjamin Franklin and Benjamin Thompson.

Benjamin Thomson, of humble origins and self-taught in his studies, through his resourcefulness, curiosity, multifacetedness and “fieldwork,” managed to gain prestigious positions in English society and was in fact appointed earl. Thomson is the father of numerous studies and disparate inventions including the discovery of convection currents, the fact that heat is not a substance but the product of the motion of particles, and the invention of the calorimeter, an apparatus for calculating the heat of combustion of wood, coal and other fuels. Through his research and experiments, he was the first to understand and use so-called radiant heat and broughtthe technique of building heating fireplaces almost to perfection.

From his practical experience and his studies on heat derived certain principles that completely changed the technique of fireplace and chimney construction hitherto adopted: “since it would be a miracle if smoke did not rise up the chimney, just as if water did not flow down the mountains,” he believed “we only need to find and remove the obstacles that prevent smoke from following its natural tendency to rise‘.

The knowledge that the heat of combustion was a heat radiant led him to modify the shape of the fireplace by decisively decreasing its depth and tilting the side walls at angles mathematically designed to maximize the radiation of heat to the room; this resulted in a fireplace that was very effective in heating and almost entirely free of smoke leakage into the rooms.

Further research turned instead to the evaluation of fuels capable of higher efficiency, such as hard coal or coke, which led to the introduction of a grate under the firebox for the air supply needed to burn these materials.

Modern Times

Around the mid-1800s, increased knowledge of physical and thermodynamic laws led to the devising of methods for making the most of the heat produced by combustion fumes as well, combining radiation with convection heating by introducing a cavity around the firebox into which air taken from the room, collected at the bottom, was introduced and heated inside it to be then reintroduced into the room, by convective motion, from the top of the appliance; hence the principle of the modern insert.

By the end of the Century, technological and metallurgical progress allowed the beginning of mass production of heating stoves and inexpensive cookstoves, at first fueled by wood and coal and later by gas, which were more efficient and less wasteful than fireplaces; the production and installation of fireplaces, as a result, dropped dramatically. The new housing dynamics and new plant technologies of the twentieth century made the fireplace, in fact, no longer an appropriate solution to the heating needs of a home, let alone a building; however, the charm and peculiar warmth of the “living flame” ensured that the fireplace never disappeared altogether, albeit likened to an “accessory” for home beautification.

In recent times, thanks to technological innovation and awareness of alternative and renewable energy sources, there has been a real rediscovery of the fireplace and stove, which have now reached very high degrees of efficiency and are often the sole source of heating and hot water production for an entire home by taking advantage of environmentally friendly and sustainable fuels.