How to Select Hearing Protection Devices for Your Facility

HPD selection is not a one-time decision — it requires matching attenuation to measured noise exposure and verifying that each worker achieves adequate protection. OSHA 1910.95 Appendix B defines the adequacy calculation. According to CDC/NIOSH, 22 million U.S. workers face hazardous noise annually, many relying on improperly selected HPDs.

Step 1: Know Your Measured TWA

HPD adequacy cannot be assessed without measured TWA data by job classification. Noise monitoring under 1910.95(d) produces the TWA data needed for Appendix B calculations. Do not select HPDs based on perceived loudness — measure first.

Step 2: Apply the OSHA NRR Derating Formula

For each HPD option and each job classification: Effective exposure = Measured TWA(A) − [(NRR − 7) ÷ 2]

Step 3: Provide Variety

OSHA requires at least one insertion-type (earplug) and one circumaural-type (earmuff). In practice, offer multiple insertion styles and at least one earmuff option. Workers who find one style uncomfortable won't wear it correctly, negating the NRR calculation entirely.

Step 4: Verify With Individual Fit Testing

The NRR derating is a population estimate. Individual workers vary. REAT-based fit testing measures each worker's actual attenuation, replacing the estimate with measured data. Workers under-protected despite the calculation are identified and refitted before their audiogram reveals the failure. See: HPD fit testing: complete employer guide.