Reference

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.

Most OSHA PELs derive from 1968 ACGIH TLVs and have not been updated since 1971 — ACGIH updates TLVs annually. For many chemicals the TLV is 5–20× lower than the PEL, requiring a higher APF respirator. ANSI/ASSP Z88.2 directs employers to use the most protective OEL. This guide covers the practical selection implications.

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.