Audiometer calibration is not a detail — it is the foundation of audiometric record validity. An audiometric test conducted with an out-of-calibration audiometer does not produce a valid OSHA record, regardless of how compliant every other aspect of the program is. OSHA 29 CFR 1910.95(h)(5) requires audiometers to be calibrated at least annually and checked acoustically before each day of testing. Audiometer calibration records that cannot be produced during an OSHA inspection or in WC litigation undermine the entire audiometric program. According to CDC/NIOSH, approximately 22 million U.S. workers undergo occupational audiometric testing annually.
OSHA Calibration Requirements Under Appendix E
OSHA 1910.95 Appendix E establishes the calibration requirements for audiometers used in HCP audiometric testing:
| Calibration Type | Frequency Required | Who Performs | What It Verifies |
|---|---|---|---|
| Biologic check | Before each day of use | Technician (tests a person with known thresholds) | Audiometer is producing audible tones; no obvious malfunction |
| Exhaustive calibration | At least annually | Qualified technician with calibrated equipment | Electroacoustic output levels, frequencies, harmonic distortion, all per ANSI S3.6 |
| Check after repairs | Whenever audiometer is repaired | Qualified technician | Full ANSI S3.6 verification after any repair that could affect calibration |
An audiometer that has not been calibrated within the required annual window is out of compliance, and any audiometric records generated during the uncalibrated period may be challenged as unreliable. In OSHA inspections, missing calibration records result in citations. In WC proceedings, opposing counsel will argue that uncalibrated audiometric results should not be admitted or given weight. Calibration records must be maintained for the life of the audiometer program.
What the Daily Biologic Check Is and Isn’t
The daily biologic check is a functional verification, not a calibration. It confirms that the audiometer is producing audible tones and that the testing person with known thresholds obtains expected results. It does not verify electroacoustic output levels or frequency accuracy to ANSI S3.6 standards. A biologic check can catch obvious malfunctions but will not detect gradual calibration drift in output levels.
Both the daily biologic check and the annual electroacoustic calibration are required. Neither substitutes for the other.
Maintain calibration records for every audiometer used in the program, including the date, technician, calibration results, and any adjustments made. Calibration records should be retained with audiometric program records — they are part of the documentation set that validates the audiometric results. In WC proceedings and OSHA inspections, the calibration record for the audiometer that generated a specific worker’s results may be specifically requested.
Frequently Asked Questions
Calibration Maintained. Records Documented. Program Defensible.
Soundtrace audiometers maintain ANSI S3.6 calibration with documented records — supporting OSHA compliance and the audiometric record validity required for WC defense.
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