How Sauna Works? 

"Temperature: between 70° C to 95° C
Humidity: 5% to 15% at level of second bench; 3% to 10% at level of third bench"

A heat source emanates warmth from wood-clad walls via stones heated in an electric or gas sauna burner, or by log fires in traditional systems. 
Saunas often contain two or three levels of benches to accommodate as many people as possible while also offering distinct temperature zones—as the heat is substantially stronger at higher levels. 
The benches are made of wood that has been specially selected for its low thermal conductivity and strong laminar strength. The benches are lattice-style with wide openings to allow air to move freely throughout the sauna.

Water infusions cause an increase in humidity, exposing the body to a brief but intense heat stimulus. A small wooden tub filled of water and a ladle were traditionally used to pour water over the hot rocks. 
Furthermore, the water was frequently infused with birch twigs to add a pleasant fragrance; birch was also thought to improve the immune system and open skin pores. Modern installations frequently use automated water dosing systems, and the infusions are typically oil essences in a variety of scents that provide different aromatherapy stimuli for body and mind.Furthermore, automatic dosing systems provide safety and efficiency benefits such as avoiding over-dosing fragrance and limiting the amount of water used, minimizing unnecessary wear on the heat source, and avoiding any water puddling.

Usage Type

 
Saunas have traditionally been used to relax and relieve muscle tension, as well as to promote circulation and the immune system. 
Saunas should be used in conjunction with cold—this can be anything from a cold shower, an ice fountain, or a "roll in the snow" in a snow room or via a snow shower—as one of the hottest therapy cabins in the hydrothermal spa. A heated, ankle-deep footbath (outside the sauna cabin) should also be considered for temperature equalization. (Because the feet have a tiny quantity of flesh and fat paired with a great number of blood arteries, they get cold and hot faster than any other body area, hence a footbath will assist regulate the body's temperature.) 

Health Advantages 

The use of heat and cold (also known as contrast therapy) ensures that a steady flow of blood is pumped through the veins, aiding in the removal of toxins from sections of the body that aren't ordinarily afforded the chance to do so (namely the skin and subcutaneous tissues). 
Immersion in both hot and cold temperatures is also thought to train the immune system, and regular sauna users seldom get mild illnesses or colds. 
Sauna Stove Heat Source: Heat is generated by specifically supplied stones, which are often deep igneous, plutonic rocks capable of absorbing and producing large amounts of heat. They are heated in the sauna stove, which is historically powered by a wood fire but is increasingly powered by electricity or gas.The size of the sauna stove is decided by the amount of heat required per cubic meter, which must be calculated by a wet-area spa specialist. For example, if the sauna has any windows or if glass is used in the design in general, the power need of the heater increases. If this is the case, there may be a health and safety concern for guests. 

Materials/Construction

Structure: In classic sauna design, soft, sustainable wood that is resin-free is desired; frequent alternatives include pine, hemlock, spruce, and cedar. When selecting wood, keep in mind that fewer knots are better because they might act as hot spots and produce unequal heat radiation.

Benches: The benches must be made of a hard, low-thermal-conductivity wood. Aspen, obeche, and poplar are suitable alternatives since they do not split and conduct little heat, so they do not burn the skin. Benches should be able to sustain a minimum of 200 kg/440 lbs per linear meter or 134 pounds per linear foot. 

Ceiling: When seated on the highest bench, the ceiling should not be higher than 226 mm over the bather's head. 

Door: Traditionally built of wood, however design trends have shifted to all glass (must be tempered safety glass). Door sizes might vary based on use and construction standards, particularly when it comes to disability access. The interior door handle must be made of wood so that it does not grow too hot to the touch. 

Windows: Although not traditional, Windows

Design

Size/Space: When developing saunas for commercial use, personal space should be considered, with a minimum of 600 millimeters allocated for each person sitting. Bathers also like to lie down in saunas, therefore it should be large enough to accommodate a two-meter-long individual.

Audio/Visual:  Consider using both lighting and noises to improve the experience. Audio, in example, is employed in commercial construction to assist break the often-uncomfortable quiet that might occur when entering a tight area with strangers. There are heat-resistant speakers made expressly for this application, as well as specialized equipment that connects both light and sound output. 

Illumination: Lighting options in saunas are quite restricted due to the fact that it must be resistant to extremely high working temperatures, particularly in the upper region of the sauna where heat is highest. Sconces, crystal glass diffusers, and fiber optic lighting are among the specialist goods available for use in saunas. Because heat is less of a concern below the first bench level, standard lighting equipment may also be acquired.

Ventilation: Saunas must be adequately ventilated in order to maintain a constant flow of oxygen in the chamber. An air extractor point is positioned near the bottom of the cabin to remove the cooler, more humid air, often through a duct installed into the wall panel that discharges the air at roof level. Fresh air will be pumped directly into the heat source, ideally seven to ten times each hour.

Special Considerations:  Sauna users must be able to monitor their sauna experience's temperature, relative humidity, and duration. This necessitates the addition of a thermometer, a hygrometer (for detecting moisture content), and a timer (ideally, a 'hour glass' monitoring appropriate time segments).

How to Use a Sauna 

• A typical sauna session lasts 90 minutes.

• Eliminate all clothes, jewelry, and contact lenses before entering the sauna. 

• Before entering the sauna, users must shower and completely dry themselves to remove any film on the skin that may delay the commencement of sweating (ideally, a foot bath should be used)

• Once in the sauna, it's best to lie down so that your entire body is in the same temperature zone; if you must sit, sit with your feet up on the same bench you're sitting on.

• The first sauna session should last eight minutes to 12 minutes (depending on how the body reacts), followed by cooling off 12 minutes to 20 minutes

• Cool off first in the air, then rinse off the sweat with cold water. It is critical to relax and chill down thoroughly after your final sauna session.