Emittance Factors for Infrared Thermometers Used for Wood Products


  • Robert W. Rice


Emittance factor, infrared thermometers


Most infrared thermometers and pyrometers require that an emissivity factor be set for the proper prediction of temperature. During this series of experiments, emittance values were measured for both solid wood and wood-based composites of various colors and surface textures. After establishing the correct values of emittance for the samples, temperature measurements were done at three temperature levels using two infrared thermometers. The thermometers were first tested using the suggested emissivity values from the manufacturer and then reset with the measured emittances. When compared, little difference between the temperature values measured with the infrared thermometers and the actual temperature values were found at room temperature, regardless of the emissivity setting. At nominal temperatures of 100 and zero Celsius, the differences in actual temperature and the temperature measured with the infrared thermometers were significant regardless of the emissivity settings.


Anon. 2003. Guide To Non Contact Temperature Measurement. Wintronics Incorporated, http://www.wintron.com/infraredIguideIR.htm'>http://www.wintron.com/infraredIguideIR.htmnASHRAE. 2001. 2001 ASHRAE Handbook- Fundamentals. American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc., Atlanta, GA.nAmerican Society of Testing and Materials (ASTM). 2003. Method E 408-71. (Reapproved 2002). Standard Test Methods for Total Normal Emittance of Surfaces Using Inspection-Meter Techniques. American Society for the Testing of Materials, West Conshohocken. PA.nBaron, W. R. 2003. Principles of Infrared Thermometry. http://www.omega.com.pdf/temperature/Z/pdf/z059-062.pdf'>http://www.omega.com.pdf/temperature/Z/pdf/z059-062.pdfnChilds, P. R. N. 2001. Practical temperature measurement. Butterworth-Heinemann, Oxford, UK. 372 pp.nDewitt, D. P., and G. D. Nutter. 1988. Theory and practice of radiation thermometry. Wiley-Interscience, New York, NY. 1138 pp.nFraden, J. 1999. Infrared thermometers. Chapter 32, Pages 32-87 in John Webster, ed. The measurement, instrumentation and sensors handbook CRC Press, Boca Raton, FL.nMichalski, L., K. Eckersdorf, J. Kucharski, and J. McGhee. 2001. Temperature measurement, 2nd ed. John Wiley and Sons, New York, NY. 501 pp.nNelson, K. E., E. E. Luedke, and J. T. Bevans. 1966. A device for the rapid measurement of total emittance. J. Spacecraft and Rockets3(5):758-760.nSmith, R. A., F. E. Jones, and R. P. Chasmar. 1968. The detection, measurement of infra-red radiation. Clarendon Press, Oxford, UK. 503 pp.n






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