OSHA 2022 Letter of Interpretation: Boothless Audiometry and ANSI S3.1 Compliance

The October 2022 OSHA Letter of Interpretation confirmed that boothless audiometric testing satisfies 1910.95 if the test environment meets ANSI S3.1-1999 ambient noise requirements. This guide explains what the LOI means and how to document compliance. OSHA Letters of Interpretation are the agency's official written clarifications of 29 CFR 1910.95 requirements. According to CDC/NIOSH, approximately 22 million U.S. workers are exposed to hazardous occupational noise annually. Note: This guide reflects OSHA's known compliance positions; always consult current OSHA guidance and legal counsel for specific situations.

Soundtrace is built around OSHA's official compliance positions — including the 2022 boothless audiometry LOI — with per-audiogram ambient noise validation, licensed audiologist Professional Supervisor review, and documentation that satisfies OSHA inspection requirements.

What the 2022 LOI Established

The October 2022 OSHA Letter of Interpretation addressed a direct question: does OSHA 1910.95 require audiometric testing to be conducted in a traditional soundproof booth? OSHA's answer was clear: no. The standard requires that the test environment meet the ANSI S3.1-1999 maximum permissible ambient noise levels at each test frequency. A traditional booth is one common way to achieve these limits, but it is not the only way.

The LOI confirmed that audiometric testing systems that measure the ambient noise level at each test frequency and compare it against ANSI S3.1-1999 MPANLs — before or during each test — can document ANSI S3.1 compliance without a traditional booth, provided the ambient levels actually meet the limits during the test session.

ANSI S3.1-1999 Requirements the LOI References

The ANSI S3.1-1999 standard (reaffirmed 2018, as incorporated into OSHA 1910.95 Appendix D) specifies maximum permissible octave-band sound pressure levels in the audiometric test environment for each test frequency:

The test environment must not exceed these octave-band levels at any test frequency during the audiogram session.

What "Boothless" Actually Means

"Boothless" audiometry does not mean testing anywhere without measurement. It means testing in a quiet, controlled environment where the ambient noise is measured and documented at the test frequencies to confirm ANSI S3.1 compliance — rather than relying on the physical attenuation of a soundproof booth to achieve the limits. A conference room that meets ANSI S3.1 at 500–6000 Hz is a compliant test environment. A break room adjacent to a noisy production floor that does not meet these limits is not — regardless of whether a booth is present.

Documentation Requirements the LOI Implies

The 2022 LOI implies that boothless audiometric testing requires documentation of the ambient noise levels at the time of each test session to demonstrate ANSI S3.1 compliance. Best practice for boothless audiometric systems: measure frequency-specific ambient noise at each test frequency at the start of each testing session (or continuously during each individual audiogram), compare to ANSI S3.1 MPANLs, and retain the ambient noise data as part of the audiometric record. Soundtrace documents ambient noise conditions per individual audiogram for every test, creating a per-test compliance record.

Implications for Employers Using Portable Audiometers

Employers who use portable audiometers in break rooms, offices, or conference rooms without verifying ambient noise conditions are not operating boothless audiometry as described in the 2022 LOI — they are operating non-compliant testing without documentation. The distinction matters: the LOI provides a path to compliant boothless testing, but that path requires ambient noise measurement and documentation. See: OSHA Appendix D: audiometric test rooms and ANSI S3.1.