High temperatures with low humidity are characteristic for hot-air rooms. Heat radiation (Infrared) comes from walls and ceiling due to the specific architecture and used materials.
They are either a massive type of construction or build with wood and other light materials.
1. The sweat lodge
The sweat lodge or sweat house (also called purification ceremony, ceremonial sauna, or simply sweat) is a ceremonial or ritual event in some cultures, particularly among some North American First Nations, Native American, Scandinavian, Baltic and Eastern European cultures. There are several styles of structures used in different cultures; these include a domed or oblong hut similar to a wickiup, a permanent structure made of wood or stone, or even a simple hole dug into the ground and covered with planks or tree trunks. Stones are typically heated and then water poured over them to create steam. In ceremonial usage, these ritual actions are accompanied by traditional prayers and songs.
Fire heating: < 100 °C / 212 °F with low humidity.
2. Traditional sauna
A tradidional finnish sauna is a small room or house designed as a place to experience dry or wet heat sessions, or an establishment with one or more of these and auxiliary facilities.
A sauna session can be a social affair in which the participants disrobe and sit or recline in temperatures typically between 70 °C (158 °F) and 100 °C (212 °F). This induces relaxation and promotes sweating.
The temperature of the air, the room and the benches is above the dew point even when water is thrown on the hot stones and vaporized. Thus, they remain dry. In contrast, the sauna bathers are at about 38 °C / 100°F, which is below the dew point, so that water is condensed on the bathers’ skin. This process releases heat and makes the steam feel hot.
95 – 105 °C (203 – 221 °F) at the ceiling with falling temperature to the ground 60°C (140 °F); low humidity: 2 – 5 %. Momentary increase of humidity when water gets poured over the oven.
3. Laconicum / Caldarium
Laconicum, the dry sweating room of the Roman thermae, contiguous to the caldarium or hot room. The name was given to it as being the only form of warm bath that the Spartans admitted. The laconicum was usually a circular room with niches in the axes of the diagonals and was covered by a conical roof with a circular opening at the top, according to Vitruvius, from which a brazen shield is suspended by chains, capable of being so lowered and raised as to regulate the temperature. The walls of the laconicum were plastered with marble stucco and painted blue with gold stars.
Here is the image of a modern Laconicium at Hotel al Sorriso Greenpark in Italy.
70 – 80 °C (158 – 176 °F) with low humidity.
In order to obtain the great heat required, the whole wall was lined with vertical terra-cotta flue pipes of rectangular section, placed side by side, through which hot air and smoke from the suspensura passed to an exit in the roof.
When Arabs and Turks overran the eastern Roman Empire, they adopted and developed this feature in their baths or hammams.
Here is the image of a modern sudatorium at Kaiser-Friedrich-Therme in Germany.
50 – 60 °C (122 – 140 °F) with low humidity.
A temazcal is a type of sweat lodge which originated with pre-Hispanic Indigenous peoples in Mesoamerica. The word temazcal comes from the Nahuatl word temazcalli (“house of heat”), or possibly from the Aztec teme (to bathe) and calli (house). In ancient Mesoamerica it was used as part of a curative ceremony thought to purify the body after exertion such as after a battle or a ceremonial ball game. It was also used for healing the sick, improving health, and for women to give birth.
It continues to be used today in Indigenous cultures of Mexico and Central America that were part of the ancient Mesoamerican region for spiritual and health reasons. It is currently being recovered by all sectors of society in that part of the world and is used as a cleansing of mind, body and spirit.
The sweatlodge in Mesoamerica is usually a permanent structure, unlike in other regions. The temazcal is usually constructed from volcanic rock and cement and is usually a circular dome, although rectangular ones have been found at certain archeological sites and this shape is also used. To produce the heat, volcanic stones are heated. Volcanic stones are safe because they do not explode from the temperature. They are then placed in a pit located in the center or near a wall of the temazcal.
80 – 100 °C (176 – 212 °F) with low humidity.
Photo Credits 1. Sweat lodge: matthewvenn via Compfight cc
3. Laconicum/Caldarium: Open air museum Petronell ( Lower Austria ). Thermae: Caldarium ( hot baths ). Wolfgang Sauber via cc
5. Temazcal:One of the temazcals at the La Chonita Hacienda in Tabasco, Mexico AlejandroLinaresGarcia via cc