The average, in decibels, of the sound-pressure levels of a noise in the three octave bands of frequency: 600–1,200, 1,200–2,400, and 2,400– 4,800 Hz {680}.. An OSH glossary used in safety and health at work which is, adopted by ILO
Barbara A. Plog, Patricia J. Quinlan, Jodey B. Schonfeld and Patricia M. Dewey (editors), Fundamentals of industrial hygiene 5th ed., Appendix E - Glossary (Michael Horowitz, MS, CIH - Compiler), National Safety Council, Illinoise, USA 2002. http://www.wbcsd.org/web/projects/cement/tf3/fihAp pendices.pdf, (Env and Occupn Sfty and Hlth - Amer) {680}