Hypocaust
Overview
 
A hypocaust was an ancient Roman
Ancient Rome
Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....

 system of underfloor heating
Underfloor heating
Underfloor heating and cooling is a form of central heating and cooling which achieves indoor climate control for thermal comfort using conduction, radiation and convection...

, used to heat houses with hot air. The word derives from the Ancient Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...

 hypo meaning "under" and caust-, meaning "burnt". The Roman architect Vitruvius, writing about the end of the 1st century B.C., attributes their invention to Sergius Orata
Sergius Orata
Sergius Orata was a famed merchant and hydraulic engineer of the Roman Republic.Sergius was well-known by his contemporaries because of the breeding and commercialization of oysters, in which he can be considered a pioneer. Orata wanted to take advantage of Romans' taste for shellfish, so he...

, but this is not fully confirmed.
Hypocausts were used for heating hot baths (thermae
Thermae
In ancient Rome, thermae and balnea were facilities for bathing...

), houses and other buildings, whether public or private.
Encyclopedia
A hypocaust was an ancient Roman
Ancient Rome
Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....

 system of underfloor heating
Underfloor heating
Underfloor heating and cooling is a form of central heating and cooling which achieves indoor climate control for thermal comfort using conduction, radiation and convection...

, used to heat houses with hot air. The word derives from the Ancient Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...

 hypo meaning "under" and caust-, meaning "burnt". The Roman architect Vitruvius, writing about the end of the 1st century B.C., attributes their invention to Sergius Orata
Sergius Orata
Sergius Orata was a famed merchant and hydraulic engineer of the Roman Republic.Sergius was well-known by his contemporaries because of the breeding and commercialization of oysters, in which he can be considered a pioneer. Orata wanted to take advantage of Romans' taste for shellfish, so he...

, but this is not fully confirmed.

Roman operation

Hypocausts were used for heating hot baths (thermae
Thermae
In ancient Rome, thermae and balnea were facilities for bathing...

), houses and other buildings, whether public or private. The floor was raised above the ground by pillars, called pilae stacks
Pilae Stacks
Pilae Stacks are stacks of pilae tiles, square thin tiles, that were used in Roman times as an element of the underfloor heating system, common in Roman bathhouses, called the hypocaust. The concept of the Pilae stacks is that the floor is constructed at an elevated position, allowing air to freely...

, with a layer of tiles then a layer of concrete then another of tiles on top; and spaces were left inside the walls so that hot air and smoke from the furnace
Furnace
A furnace is a device used for heating. The name derives from Latin fornax, oven.In American English and Canadian English, the term furnace on its own is generally used to describe household heating systems based on a central furnace , and sometimes as a synonym for kiln, a device used in the...

 would pass through these enclosed areas and out of flues in the roof, thereby heating but not polluting the interior of the room. Ceramic box tiles were placed inside the walls to both remove the hot burned air, and also to heat the walls. Rooms requiring the most heat were placed closest to the furnace, whose heat could be increased by adding more wood to the fire. It was labour-intensive to run a hypocaust as it required constant attention to tend the fire, and expensive in fuel, so it was a feature of the villa
Villa
A villa was originally an ancient Roman upper-class country house. Since its origins in the Roman villa, the idea and function of a villa have evolved considerably. After the fall of the Roman Republic, villas became small farming compounds, which were increasingly fortified in Late Antiquity,...

 and public baths.

Vitruvius
Vitruvius
Marcus Vitruvius Pollio was a Roman writer, architect and engineer, active in the 1st century BC. He is best known as the author of the multi-volume work De Architectura ....

 describes their construction and operation in his work De architectura
De architectura
' is a treatise on architecture written by the Roman architect Vitruvius and dedicated to his patron, the emperor Caesar Augustus, as a guide for building projects...

in about 15 BC, adding details about how fuel could be conserved by designing the hot room or caldarium
Caldarium
right|thumb|230px|Caldarium from the Roman Baths at [[Bath, England]]. The floor has been removed to reveal the empty space where the hot air flowed through to heat the floor....

 for men and women to be built next to one another, adjacent to the tepidarium
Tepidarium
The tepidarium was the warm bathroom of the Roman baths heated by a hypocaust or underfloor heating system.The specialty of a tepidarium is the pleasant feeling of constant radiant heat which directly affects the human body from the walls and floor.There is an interesting example at Pompeii; this...

 so as to run the public baths efficiently. He also describes a device for adjusting the heat by a bronze
Bronze
Bronze is a metal alloy consisting primarily of copper, usually with tin as the main additive. It is hard and brittle, and it was particularly significant in antiquity, so much so that the Bronze Age was named after the metal...

 ventilator in the domed ceiling.

Many remains of Roman hypocausts have survived throughout Europe, western Asia, and northern Africa. The hypocaust was an invention which improved the hygiene and living conditions of citizens, and was a forerunner of modern central heating
Central heating
A central heating system provides warmth to the whole interior of a building from one point to multiple rooms. When combined with other systems in order to control the building climate, the whole system may be a HVAC system.Central heating differs from local heating in that the heat generation...

.

Non-Roman example

Excavations at Mohenjo-daro
Mohenjo-daro
Mohenjo-daro is an archeological site situated in what is now the province of Sindh, Pakistan. Built around 2600 BC, it was one of the largest settlements of the ancient Indus Valley Civilization, and one of the world's earliest major urban settlements, existing at the same time as the...

 in what is now Pakistan
Pakistan
Pakistan , officially the Islamic Republic of Pakistan is a sovereign state in South Asia. It has a coastline along the Arabian Sea and the Gulf of Oman in the south and is bordered by Afghanistan and Iran in the west, India in the east and China in the far northeast. In the north, Tajikistan...

 have unearthed what is believed to be a hypocaust lined with bitumen-coated bricks. If so, the structure would pre-date the earliest Roman hypocaust by as much as 2000 years.

After the Romans

With the decline of the Roman Empire, the hypocaust fell into disuse, especially in western provinces. In Britain, from c. 400 until c. 1900, central heating did not exist, and hot baths were rare.

In Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...

 the Roman system was adopted for the heating of Hispano-Islamic (Al Andalus) baths (hammams).
A derivation of hypocaust, the gloria
Gloria (heating system)
Gloria was a central heating system used in Castile beginning in the Middle Ages. It was a direct descendant of the Roman hypocaust, and due to its slow rate of combustion, it allowed people to use smaller fuels such as hay instead of wood.-Description:The Gloria consisted of a firebox, generally...

, was in use in Castile
Castile (historical region)
A former kingdom, Castile gradually merged with its neighbours to become the Crown of Castile and later the Kingdom of Spain when united with the Crown of Aragon and the Kingdom of Navarre...

 until the arrival of modern heating. After the fuel (mainly wood) was reduced to ashes, the air intake was closed to keep hot air inside and to slow combustion
Combustion
Combustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...

.

Korean traditional houses sometimes use an ondol
Ondol
An ondol, also called gudeul, in Korean traditional architecture, is underfloor heating which uses direct heat transfer from wood smoke to the underside of a thick masonry floor...

, which is similar to a hypocaust, drawing smoke from a wood fire typically used for cooking.

See also

  • De Architectura
    De architectura
    ' is a treatise on architecture written by the Roman architect Vitruvius and dedicated to his patron, the emperor Caesar Augustus, as a guide for building projects...

  • Roman engineering
    Roman engineering
    Romans are famous for their advanced engineering accomplishments, although some of their own inventions were improvements on older ideas, concepts and inventions. Technology for bringing running water into cities was developed in the east, but transformed by the Romans into a technology...

  • Roman technology
    Roman technology
    Roman technology is the engineering practice which supported Roman civilization and made the expansion of Roman commerce and Roman military possible over nearly a thousand years....

  • Ondol
    Ondol
    An ondol, also called gudeul, in Korean traditional architecture, is underfloor heating which uses direct heat transfer from wood smoke to the underside of a thick masonry floor...

  • Gloria in the Spanish Wikipedia.
  • Masonry heater
    Masonry heater
    A masonry heater is a device for warming a home that captures the heat from periodic burning of fuels , and then radiates that heat over a long period at a fairly constant temperature. The technology exists in many forms from the Roman hypocaust to the Austrian/German kachelofen...

     (similar to Kachelofen in the German Wikipedia).
  • Kang bed-stove
    Kang bed-stove
    The Kang is a traditional long sleeping platform made of bricks or other forms of fired clay and more recently of concrete in some locations. Its interior cavity, leading to a flue, channels the exhaust from a wood or coal stove...

  • Vitruvius
    Vitruvius
    Marcus Vitruvius Pollio was a Roman writer, architect and engineer, active in the 1st century BC. He is best known as the author of the multi-volume work De Architectura ....

  • Underfloor heating
    Underfloor heating
    Underfloor heating and cooling is a form of central heating and cooling which achieves indoor climate control for thermal comfort using conduction, radiation and convection...

    , (history)

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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