Raymond F. Feldman
U.S. Dept. of Labor, OSHA Cincinnati Lab., USPO Bldg., Room 108, 5th & Walnut St., Cincinnati, OH 45202
Acoustical instruments are more susceptible to radio interference than many users find acceptable. Degraded performance caused by electromagnetic fields is called electromagnetic susceptibility (EMS). In the past, performance standards for acoustical instruments, and all industrial hygiene instruments in general, have not adequately addressed this problem. EMS deficiencies can range from subtle deviations to gross errors in sound measurements. It has even been reported, that EMS has caused audiometers to malfunction and blast the ears of patients with sound levels of 80 and 90 dBA. The OSHA Cincinnati Laboratory has been working to reduce EMS effects on sound instruments that are used by OSHA and MSHA. Manufacturers are being persuaded to meet EMS performance specifications for instruments which these agencies purchase. These requirements assure the instruments will operate properly in industrial and mining environments. In 1992, ASA established an ANSI/ASA working group to write an EMS standard for acoustical instruments.