History mystery: Hypocaust

Hypocaust, one of the ancient forms of heating system in underground heating with hot air, originated with the Romans, 2000 years ago and was both a primary as well as secondary system for houses and building for both public and private purpose. Hypocaust is derived from the Greek work `hypo’ meaning `under’ and `caust’ meaning `burnt’. The main use of hypocaust was found in large bath houses and sauna rooms were made by adding water as a pool which was heated by fire and also the air below. The floor was raised above ground level by pillars, or columns or pedestals of stone, called pile stack which had layer of tiles, followed by layer of concrete to top the tile.

 A furnace with continuous burning fire created heat which then flowed through the space below the raised floor, providing heat to the floor and the rest of the room and once cooled the air escaped through flues in the wall and through vents in the roof. Since the furnace area needed to be spacious, it was usually located in a separate area of the room and the flues were constructed in a way that it did not utilize any extra space. This enabled the heating without polluting the interior of the room. Ceramic box tiles were also placed inside the walls in order to remove the hot burned air as well as to heat the walls and where rooms in need of more heat, were placed closer to the furnace.

This heat could be increased on adding more wood to the fuel. This involved a lot of labor and constant attention was needed to keep the fire burning as well as expensive. The purpose of the hypocaust was to heat the room evenly. Similar to the water system, the air flow system was also connected by ducts comprising of brick or stone tunnels built underground towards large open space beneath raised floor ending into wall flues. These flues were provided with insulation for the room and the hot air rising created a barrier thereby retaining the warmth inside the building. One of the main disadvantages of the hypocaust was that it seemed dangerous when the fumes created by the furnace in the form of carbon monoxide crept out of the spaces below the false floor and in the main space and though this is detectable and preventable today, in those days, the Romans had no knowledge about the same. Another disadvantage was that with this system, there could have been the possibility of a fire break out which could be unmanageable and out of control. While the concrete or stone construction could have withstood the fire, the occupants would be in danger.

This system seemed to be useful in ancient times but keeping in mind the safety codes, it is impossible to install them in modern times since the hypocaust system in high probability would be causing the occupant discomfort resulting in falling ill or even the possibility of dying from carbon dioxide or poisoning. Control on the hypocaust system is not user controlled due to the fact of the heat coming off from an open flame and for this reason; there are two setting for this system of on and off.