The November 2023 Change 1 to DoD Instruction 6055.12 introduced mandatory Personal Attenuation Rating (PAR) fit testing for all service members and DoD civilian employees with documented noise exposures exceeding 95 dBA 8-hour TWA — the most operationally significant new hearing conservation requirement in recent DoD history. This guide explains what PAR testing is, who it applies to, how it differs from OSHA’s NRR baseline, and what safety managers need to know about implementation.
DoDI 6055.12 Change 1 (November 22, 2023): All service members and DoD civilian employees with documented noise exposures exceeding 95 dBA TWA must receive initial hearing protector fit testing using PAR methodology — going beyond what OSHA 1910.95 requires.
What the 2023 Update Changed
Prior to Change 1, DoDI 6055.12 — like OSHA 1910.95 — required hearing protectors to provide adequate attenuation based on NRR de-rating methods. Change 1 adds a direct measurement requirement for the highest-exposed workers: workers with documented exposures above 95 dBA TWA must now be individually fit tested to confirm their specific device delivers adequate protection. NRR-based estimation continues for workers below the 95 dBA TWA threshold.
What PAR Fit Testing Is and How It Works
- The worker dons their hearing protector as they normally would
- The fit-testing system generates a calibrated sound field
- Sound levels are measured inside and outside the ear canal simultaneously
- The difference yields the Personal Attenuation Rating (PAR) for this individual
- If PAR is insufficient, the worker tries different devices or fitting approaches until adequate attenuation is confirmed
NRR represents a population average from laboratory testing. PAR represents this person, today, wearing this device this way. A worker who achieves a PAR of 12 dB may have an NRR de-rated value suggesting 15–20 dB of protection. For workers above 95 dBA TWA, that gap is the difference between adequate and inadequate protection.
PAR vs. NRR De-Rating
| Dimension | NRR De-Rating (OSHA baseline) | PAR Fit Testing (DoDI 6055.12, 2023) |
|---|---|---|
| What is measured | Population-average attenuation; de-rated for field use | Actual attenuation for this individual at this fitting |
| Individual variation | Not captured | Directly measured; poor fit immediately visible in score |
| Training benefit | None inherent | Immediate — worker sees score improve with better technique |
| Required by OSHA 1910.95 | Yes — Appendix B adequacy methods | No — PAR exceeds the OSHA baseline |
| Required by DoDI 6055.12 | Yes — for workers below 95 dBA TWA | Yes — required for workers above 95 dBA TWA (Change 1, 2023) |
Who the Mandate Applies To
- Covered: Service members with documented noise exposures exceeding 95 dBA TWA
- Covered: DoD civilian employees with documented noise exposures exceeding 95 dBA TWA
- Not covered: Personnel at or below 95 dBA TWA — NRR adequacy estimation continues
- Not covered: Defense contractors — OSHA 1910.95 applies; fit testing not required by OSHA
- Trigger is documented exposure: Noise monitoring is a prerequisite to determine who requires PAR fit testing
The requirement is triggered by documented exposures. Noise monitoring is required before you can determine who requires PAR fit testing. Installations with outdated surveys for high-noise areas may have a documentation gap that prevents correct implementation.
Why PAR Testing Matters Beyond Compliance
Real protection confirmation: For workers above 95 dBA TWA, HPDs are the primary control. Confirming actual attenuation — not just that the NRR calculation suggests adequate protection — directly reduces hearing loss risk in the highest-exposure population.
Documentation value: A documented PAR score is stronger evidence of adequate protection than an NRR de-rating calculation in workers’ compensation or VA disability proceedings.
Implementation Status
As of 2025, the Defense Centers for Public Health – Aberdeen is conducting implementation studies across installations. DHA is developing equipment procurement pathways and technician training programs. Installation HROs should contact their DHA Public Health representative for current timelines specific to their installation.
Implications for DoD Civilian Safety Managers
- Civilian employees at depots, arsenals, and shipyards with documented exposures above 95 dBA TWA are in scope
- The civilian safety manager has a compliance obligation to address this for the civilian workforce — not just the military HRO
- Civilian PAR scores should be documented in audiometric records and retained per 29 CFR 1910.95(m)
Frequently Asked Questions
PAR (Personal Attenuation Rating) testing measures the actual noise reduction achieved by a specific hearing protector on a specific individual — not a population-average estimate from the NRR label. A portable system measures sound levels inside and outside the ear with the device worn, yielding a real protection score.
All service members and DoD civilian employees with documented noise exposures exceeding 95 dBA 8-hour TWA. Workers below the 95 dBA TWA threshold continue with NRR adequacy estimation. Defense contractors are not subject to the DoDI requirement.
No. OSHA 1910.95 does not require hearing protector fit testing. PAR testing exceeds the OSHA baseline and is currently required only by DoDI 6055.12 Change 1 for DoD personnel with documented exposures above 95 dBA TWA.
DoD Civilian HCP Support
Soundtrace supports DoD civilian safety managers with automated audiometric testing, audiologist review on every record, and documentation satisfying both OSHA 1910.95 and DoDI 6055.12 — including awareness of the 2023 PAR fit-testing mandate.
Request a Federal Program Assessment- Federal Government & DoD Hearing Conservation: The Complete Compliance Guide
- DoDI 6055.12: Complete Guide for DoD Civilian Safety Managers
- DOEHRS-HC Explained: DoD’s Audiometric Data System
- Government Contractor Hearing Conservation: Which Standard Applies?
- OSHA Hearing Conservation Program: The Complete Guide
- Workers’ Compensation for Occupational Hearing Loss: 50-State Guide