# Air-Purifying Respirator — Respirator assigned protection factors — federal OSHA and Cal/OSHA, with maximum use concentrations

For Air-Purifying Respirator, facepiece is Half mask; assigned protection factor is 10; jurisdiction is 29 CFR 1910.134; conditions is This APF category includes filtering facepieces, and half masks with elastomeric facepieces, recorded from its source on 2026-08-10.

- **Respirator type:** Air-Purifying Respirator _(verified: appears in the quote below)_
- **Facepiece:** Half mask _(our reading, not quoted from the source)_
- **Assigned protection factor:** 10 _(verified: appears in the quote below)_
- **Jurisdiction:** 29 CFR 1910.134 _(our reading, not quoted from the source)_
- **Conditions:** This APF category includes filtering facepieces, and half masks with elastomeric facepieces. _(verified: appears in the quote below)_

## What the source says

> Type of respirator 1 2 | Quarter mask | Half mask | Full facepiece | Helmet/hood | Loose-fitting facepiece | 1. Air-Purifying Respirator | 5 | 3 10 | 50 | | | 2. Powered Air-Purifying Respirator (PAPR) | | 50 | 1,000 | 4 25/1,000 | 25 | 3. Supplied-Air Respirator (SAR) or Airline Respirator | | | | | | • Demand mode | | 10 | 50 | | | • Continuous flow mode | | 50 | 1,000 | 4 25/1,000 | 25 | • Pressure-demand or other positive-pressure mode | | 50 | 1,000 | | | 4. Self-Contained Breathing Apparatus (SCBA) | | | | | | • Demand mode | | 10 | 50 | 50 | | • Pressure-demand or other positive-pressure mode (e.g., open/closed circuit) | | | 10,000 | 10,000 | | Notes: | 1 Employers may select respirators assigned for use in higher workplace concentrations of a hazardous substance for use at lower concentrations of that substance, or when required respirator use is independent of concentration. | 2 The assigned protection factors in Table 1 are only effective when the employer implements a continuing, effective respirator program as required by this section ( <https://www.ecfr.gov/current/title-29/section-1910.134> 29 CFR 1910.134 ), including training, fit testing, maintenance, and use requirements. | 3 This APF category includes filtering facepieces, and half masks with elastomeric facepieces. |

## Source

- https://www.ecfr.gov/current/title-29/subtitle-B/chapter-XVII/part-1910/subpart-I/section-1910.134

Last verified: 2026-08-10. Review by: 2028-08-09.
Part of [Respirator assigned protection factors — federal OSHA and Cal/OSHA, with maximum use concentrations](https://referencesource.org/respirator-assigned-protection-factors/).