Research
Blackstone Saunas is unique in that one of our owners is a Scientific Researcher! This ensures that all we produce and sell is not only well researched, but also that our customers are well informed on all research practices and health benefits of Infrared saunas. Additionally, our staff is well versed on all of our products and their effective usage.
(Following excerpt from: Need for Heat: A Complete Guide to Far Infrared Saunas by Dr. Kathie M. Black).
What Is Infrared?
Heat is heat – but sources of heat vary. Infrared commonly refers to the warm heat as related to heat from the sun. This chapter explains the electromagnetic spectrum as it applies to infrared heat, as well as how infrared saunas efficiently and effectively apply this heat for healing.
Electromagnetic Spectrum
The electromagnetic spectrum includes all waves generated from the sun. The word infrared means “below red,” as these waves are just below those of visible red light. Although we cannot see infrared light, we feel it as heat in the increased warmth of our skin. While we feel the heat from these rays, they are below the visible light spectrum and cause no damage to our skin as ultra violet rays can. Infrared waves penetrate and heat objects by exciting the molecules in the object, causing them to move together, producing heat.
What Is Radiant Heat?
Radiant heat is a form of energy that heats objects directly through conversion without heating the surrounding air. This radiant heat is from the infrared band of the electromagnetic spectrum, divided into three wavelength segments measured as microns or micrometers. The near or close infrared spectrum falls between 00.76 to 1.5 microns; the middle or intermediate between 1.5 to 5.6 microns; and the far infrared spectrum falling between 5.6 to 1000 microns. Far infrared falls just below visible light on the electromagnetic spectrum (Flickstein, 2000). [See diagram].
Here’s another way to view the spectrum. Perhaps this is a bit easier to understand:
The History Of Infrared Science
William Herschel ‘discovered’ infrared heat during the 19th century. He held a prism up to light from the sun and observed the refraction of light in a prism. While he was conducting this experiment he found a section of heat directly below red on the spectrum as measured by a thermometer. He originally called these rays “Calorific Rays” and proceeded to publish his results with the Royal Society of London in 1800.
Historical advances in Infrared
1835 Macedonio Melloni makes the first thermopile IR detector
1860 Gustav Kirchhoff formulates the blackbody theorem E = J(T,n)
1873 Willoughby Smith discovers the photoconductivity of selenium
1879 Stefan-Boltzmann law formulated empirically that the power radiated by a blackbody is proportional to T4
1880s & 1890s Lord Rayleigh and Wilhelm Wien both solve part of the blackbody equation, but both solutions are approximations that “blow up” out of their useful ranges. This problem was called the “UV Catastrophe and Infrared Catastrophe”
1901 Max Planck published the blackbody equation and theorem. He solved the problem by quantizing the allowable energy transitions
1905 Albert Einstein develops the theory of the photoelectric effect, determining the photon. Also William Coblentz in spectroscopy and radiometry.
1917 Theodore Case develops thallous sulfide detector; British develop the first infrared search and track (IRST) in World War I and detect aircraft at a range of one mile (1.6 km)
1935 Lead salts – early missile guidance in World War II
1938 Teau Ta predicted that the pyroelectric effect could be used to detect infrared radiation
1945 The Zielgerät 1229 “Vampir” infrared weapon system is introduced as the first portable infrared device to be used in a military application
1952 H. Welker discovers InSb
1950s Paul Kruse (at Honeywell) and Texas Instruments form infrared images before 1955
1950s and 1960s Nomenclature and radiometric units defined by Fred Nicodemenus, G.J. Zissis and R. Clark, Jones defines D*
1958 W.D. Lawson (Royal Radar Establishment in Malvern) discovers IR detection properties of HgCdTe
1958 Falcon & Sidewinder missiles developed using infrared and the first textbook on infrared sensors appears by Paul Kruse, et al.
1961 J. Cooper demonstrated pyroelectric detection
1962 Kruse and Rodat advance HgCdTe; Signal Element and Linear Arrays available
1965 First IR Handbook; first commercial imagers (Barnes, Agema {now part of FLIR Systems Inc.}). Richard Hudson’s landmark text; F4 TRAM FLIR by Hughes; phenomenology pioneered by Fred Simmons and A.T. Stair; U.S. Army’s night vision lab formed (now Night Vision and Electronic Sensors Directorate (NVESD); and Rachets develops detection, recognition and identification modeling while there
1970 Willard Boyle & George E. Smith propose CCD at Bell Labs for picture phone
1972 Common module program started by NVESD
1978 Infrared imaging astronomy comes of age, observatories planned, IRTF on Mauna Kea opened; 32 by 32 and 64 by 64 arrays are produced in InSb, HgCdTe and other materials
Applications Of Far Infrared
Today infrared technology is used in a multitude of purposes from heaters to imaging. Infrared technology is most widely known for use in military and law enforcement for night filters or tracking of objects by their heat signature.
Every physical body – whether it is living or non-living – gives off a certain amount of heat. This is known in science as the “Blackbody Radiation Law.” We can virtually “see” any object by the heat emitting from that object. You may have seen night vision goggles in movies or in person – allowing the user to see at night by tracking the heat of an object. Thermography is the method that scientists use to measure the temperature of objects. Infrared is used in imaging of digital cameras and cell phones as well as in different types of communications. You will find infrared technology in spectroscopy, climatology, astronomy and interestingly, in art history. Art historians use infrared technology on old paintings to determine if there is a hidden under-layer to paintings or works of art. For our purposes, we focus only on the heating value of infrared for this book. I will discuss different methods of heating either through ceramic or carbon fibre heaters later on.
The International Commission on Non-Ionizing Radiation Protection (ICNIRP) (2006) published a statement exploring infrared exposure on humans with respect to biological tissues. It gives a solid definition of infrared rays along with excellent graphs and descriptions of infrared wave penetration at various wavelengths. The ICNIRP statement also gives a clear explanation of how infrared waves as produced in saunas affect the skin, eyes, and other biological tissues. It states adequate exposure times and gives a caution to using an infrared sauna if one has skin cancer.
Infrared Saunas
Finnish saunas and other conventional hot air saunas heat only the air around them at high temperatures between 150-500° F. An Infrared sauna produces infrared waves at lower temperatures that penetrate the skin to approximately 1.5” or 3.81 cm, increasing the body’s temperature internally and more quickly than merely sitting in a hot environment. Infrared saunas provide greater benefits at lower temperatures resulting in more effective sauna sessions for the user.
Heaters used in infrared saunas emit approximately one third of their waves in the middle to intermediate portion of the infrared band of the electromagnetic spectrum: 2 to 5.6 microns. However, what makes them so effective is that two thirds of their emission falls in the deep body penetration range of 5.6 to 25 microns- with the average wave length being 9.4 microns- which happens to be the optimal point for human heating output (Flickstein, 2000).
Here is a visual representation of this optimal range in the infrared band of the electromagnetic spectrum:
Transition From Traditional Hot Rock To Infrared
Finnish culture used saunas for ancient religious ceremonies involving mental, spiritual, and physical cleansing from well before 5,000 and 3,000 BC. Traditional sauna use stayed with the Finns long after they migrated from areas northwest of Tibet to their present geographical location of Finland. Native American Indians incorporated sweat lodges for cleaning and purifying as well in their spiritual ceremonies. Japanese researcher Dr. Tadashi Ishikawa received a patent in 1965 for use of the first zirconium ceramic infrared heater in the use of healing thermal systems. Japanese health professionals were the only ones using infrared heat therapy until 1979 when the patent was released for public use. Flickstein (2000) states however, that there was use of infrared heat therapy in Germany for the past 80 years. Since the release of the patent in 1979, infrared heat has been used in the form of panels in hospital nurseries to warm newborns (Flickstein, 2000).
Infrared heaters only heat approximately twenty percent (20%) of the surrounding air, leaving eighty percent (80%) of the heating waves available to directly heat the body. This direct heating of the body is preferable to indirect heating from traditional or conventional saunas, which only heat the air to between 50-125°F (10-52°C). A far-infrared heater creates penetrating heat for the body while leaving the surrounding air cool to breathe. Many sauna users report discomfort breathing the hot air in a traditional sauna and a much great feeling of well-being after breathing the cooler air in a far-infrared sauna (Flickstein, 2000).
References
Flickstein, A.M., (2000). Infrared Radiant Energy. Health Mate Sauna Article. ISSU 202, pages 66-74.
The International Commission on Non-Ionizing Radiation Protection (ICNIRP) Statement on Far Infrared Radiation Exposure. (2006). Health Physics. December 2006, Volume 91, Number 6.
For more images, Google “Electromagnetic spectrum”
Electromagnetic Spectrum: http://science.hq.nasa.gov/kids/imagers/ems/index.html
Wikipedia. http://en.wikipedia.org/wiki/Infrared
(Excerpt from: Need for Heat: A Complete Guide to Far Infrared Saunas by Dr. Kathie M. Black).
