42 CFR § 84.175 - Instantaneous filter efficiency level determination test—PAPR series HE, PAPR100-N, and PAPR100-P filtration.

---
identifier: "/us/cfr/t42/s84.175"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "42 CFR § 84.175 - Instantaneous filter efficiency level determination test—PAPR series HE, PAPR100-N, and PAPR100-P filtration."
title_number: 42
title_name: "Public Health"
section_number: "84.175"
section_name: "Instantaneous filter efficiency level determination test—PAPR series HE, PAPR100-N, and PAPR100-P filtration."
chapter_name: "PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES"
subchapter_number: "G"
subchapter_name: "OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES"
part_number: "84"
part_name: "APPROVAL OF RESPIRATORY PROTECTIVE DEVICES"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "29 U.S.C. 651  30 U.S.C. 3, 5, 7, 811, 842(h), 844."
regulatory_source: "60 FR 30355, June 8, 1995, unless otherwise noted."
cfr_part: "84"
---


# 84.175 Instantaneous filter efficiency level determination test—PAPR series HE, PAPR100-N, and PAPR100-P filtration.

(a) Three filters from each powered air-purifying particulate respirator for efficiency will be tested against a neat cold-nebulized dioctyl phthalate (DOP) or equivalent aerosol at 25 ± 5 °C that has been neutralized to the Boltzmann equilibrium state.

(b) Single air-purifying particulate respirator filter units will be tested in an atmosphere concentration of 100 mg/m
<sup>3</sup> of DOP at the following continuous flow rates for a period of 5 to 10 seconds:

| Type of respiratory inlet
covering | Airflow rate
(liters per
minute) |
| --- | --- |
| Tight-fitting | 115 |
| Loose-fitting | 170 |

(c) Powered air-purifying particulate respirators with multiple filter units will be tested by dividing the flow rate specified in paragraph (b) of this section by the total number of filters used.

(d) The filter will be mounted on a connector in the same manner as used on the respirator and the total efficiency must be ≥99.97 percent.