Reference

Hearing protector fit testing measures what one worker actually gets from one earplug, reported as a personal attenuation rating in decibels. OSHA's February 2026 bulletin calls it a best practice but says a PAR cannot replace the NRR for selection. Covers NRR versus PAR, the 2025 NIOSH change, target PAR, and a worked example.

Respiratory protective equipment (RPE) is the umbrella term for every device that protects breathing — from disposable N95s and FFP3s to powered and supplied-air systems. This guide maps the full family tree, the adequate-and-suitable selection test, fit testing rules, and how the US, UK, EU, Canadian, and Australian rulebooks attach.

Assigned protection factors (APF) are the protection levels OSHA assigns to each respirator class in 29 CFR 1910.134 Table 1. This guide decodes the APF table from quarter mask to pressure-demand SCBA, shows how APF and the exposure limit set the maximum use concentration, and works an example of picking a respirator from a measured exposure.

OSHA 29 CFR 1910.134 governs respiratory protection programs across general industry and construction. This guide covers every major section: written programs, APF selection, medical evaluations, fit testing, user seal checks, cartridge change-out, IDLH requirements, training, recordkeeping, and a step-by-step compliance example.

ANSI/ASSP Z88.2 is the consensus respiratory protection program standard, providing guidance that goes beyond OSHA 1910.134 minimums. It covers hazard identification, respirator selection, written programs, fit testing, and program evaluation. This guide explains Z88.2's structure and how it relates to 1910.134 and NIOSH 42 CFR Part 84.

OSHA 29 CFR 1926.103 is the construction respiratory protection standard. It requires all construction employers to comply with 29 CFR 1910.134 — including written programs, medical evaluations, and fit testing. This guide covers APF selection, silica and asbestos rules, common citation triggers and a worked example for concrete grinding.

What Happens If a Respirator Doesn't Fit: A respirator that does not seal properly against the face stops working as rated. Fit failure collapses the assigned protection factor (APF) - a half-face respirator with an APF of 10 can deliver as little as 2× protection if the face seal leaks.