SKIN AND SUBCUTANEOUS TEMPERATURE CHANGES DURING EXPOSURE TO INTENSE THERMAL RADIATION
Abstract
Radiometric measurements have been made of the skin temperature changes occurring during irradiation of the body by high intensity thermal radiation with square wave pulses. Quartz lamps operated at 50% overvoltage provided a source of color temperature 2650K and a uniform (=5%) irradiance of 0.15 gm cal/sec/square cm over areas of 40x30cm. A spring operated focal-plane shutter controlled exposure times from 2-120 seconds with a rise time of 0.01 seconds. The radiometer, mounted between the quartz lamps so as to view the skin from normal incidence, had a 96% response time of 0.1 seconds and a precision of =0.1C. Significant corrections were necessary to allow for the far infrared reflection from the human skin; a reflectivity of 1.5% was measured for the white skin in the spectral region 3.7 microns to 30 microns. The experimental values of skin temperature rise during irradiation were compared with those calculated by the finite differences method for various skin layers with the best available values for optical and thermal properties of each skin layer, using an analog computer. During the initial 10-15 sec of irradiation theoretical and experimental values are in agreement, indicating passive responses. For longer exposures, it is concluded that physiological responses such as vasodilation and sweating slow the skin temperature rise. Subcutaneous temperatures can be calculated from surface temperature data; it is indicated that most of the radiation is absorbed in the first 0.05 0.15 mm of skin through combined effects of absorption and scattering. Some of the radiation of wavelength near 1 micron penetrates to a depth of 5 mm or more
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1964
- Accession Number
- AD0615477
Entities
People
- J. A. Stolwijk
- J. D. Hardy