George Paul Wilson
Wilson, Ihrig & Assoc., Inc., 5776 Broadway, Oakland, CA 94618
Accurate and supportable measurements of noise levels require the user/consultant to frequently ``calibrate'' acoustical instrumentation, usually under ``field'' rather than laboratory conditions. Field use calibrators are subject to a variety of environmental and use conditions, but must maintain accuracy and have calibrations traceable to NIST standards. In many instances the measurement data are used as facts in litigation or to establish compliance with ordinances and applied standards. Other uses include comparison with measurement data by others, with previous data and with projections. A description of calibration and verification methods employed by consultants is presented along with an assessment of their effectiveness. Also, presented are comments on the need for education of users in the use and significance of instrument calibration and the requirement for frequent ``traceable'' confirmations of calibration. Of particular importance is the concept and use of a system calibration which includes all relevant instrumentation components.