34:15-35.16. Hearing tests; instruments; test conditions.
Hearing levels shall be determined at all times by using puretone air-conduction audiometric instruments calibrated in accordance with American National Standard ANSI S3.6-1969-R 1973 and ANSI S3.13-1972 and performed in an environment as prescribed by American National Standard S3.1-1960 R 1971 (American Standard Criteria for Background Noise in Audiometer Rooms). To measure permanent hearing loss, hearing tests shall be performed after at least 16 hours absence from exposure to hazardous noise. The calibration of an audiometric instrument used to measure permanent hearing loss shall have been performed within 1 year of the time of the hearing examination, to assure that the audiometer is within the tolerances permitted by the ANSI standards.