Reference

OSHA's noise rule runs on two numbers: a 90 dBA permissible exposure limit and an 85 dBA action level that triggers the full hearing conservation program. This guide walks Table G-16's time limits, the OSHA-vs-NIOSH exchange-rate gap, real-world NRR derating, and a worked compliance example for a 92 dBA fabrication shop.

The NRR on every earplug and earmuff is a laboratory number, not the protection you actually get on the floor of a plant. This guide shows you how to read the NRR on the EPA label, apply the OSHA 50 percent derating rule and the NIOSH (NRR-7)/2 formula, and calculate combined attenuation when you double up earplugs and earmuffs together.