Guide to UV Measurement
Introduction to the RadTech UV Glossary
Reprinted from The RadTech Report , March/April 2002
The UV Measurement Task Force was formed in January, 2000, under the Technical Committee of RadTech North America. Among its chartered tasks is providing technical information to users, potential users, researchers and manufacturers in the technology and terminology of UV measurement and the promotion of good practices and standards in UV measurement. The task force consists of formulators, researchers, and manufacturers of UV lamps and UV radiometers
One of the first obstacles encountered was the loose and sometimes incorrect use of optical terms in the reporting of UV "curing" data. Very often in published papers, the exposure conditions were omitted or incompletely described, a few authors still content with describing exposure in "watts per inch." It became clear that there are issues of awareness, usage, understanding and terminology of radiometric measurements and the reasons for making them.
In addressing these separate issues, the Measurement Task force has encouraged and stimulated the presentation of technical papers, publication of articles, and conduct of workshops on Measurement and Control. In fact, RadTech 2002 will include an entire technical session devoted to UV Measurement and Control.
One of the projects identified by the Task Force was the generation of a glossary of terms used in our technology. A purpose of the glossary is to help guide the use of proper technical terms, and to try to further reduce the use of improper or undefined "street words" in technical papers and articles. (We have come a long way since 1995 when we set out replace the much-abused term "intensity" with the more correct optical term "irradiance"). There are several cases where the preferred term is indicated.
A number of issues arise from some difference in terms or their abbreviations applied by various bodies and disciplines. Science has struggled with various "dialects" in technical language for years. In the preparation of the Glossary, we worked with several other organizations and appreciate the assistance provided by The National Institute of Standards (NIST), The International Ultraviolet Association (IUVA), The Council on Optical Radiation Measurements (CORM), and input from ASTM, CIE, and IUPAC (International Union of Pure and Applied Chemistry).
Part of the difficulty with this project is that it could expand forever. We have tried to limit the content to terms that relate to measurement and specification of UV exposure in curing technology. Fifty words and five pages was our guideline. The glossary is a first effort to help bring some common (and correct) language into use in the Process Design and Measurement part of our technology.