42 CFR § 84.156 - Airflow resistance test; Type C supplied-air respirator, demand class; minimum requirements.

---
identifier: "/us/cfr/t42/s84.156"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "42 CFR § 84.156 - Airflow resistance test; Type C supplied-air respirator, demand class; minimum requirements."
title_number: 42
title_name: "Public Health"
section_number: "84.156"
section_name: "Airflow resistance test; Type C supplied-air respirator, demand class; minimum requirements."
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"
---


# 84.156 Airflow resistance test; Type C supplied-air respirator, demand class; minimum requirements.

(a) Inhalation resistance shall not exceed 50 millimeters (2 inches) of water at an air flow of 115 liters (4 cubic feet) per minute.

(b) The exhalation resistance to a flow of air at a rate of 85 liters (3 cubic feet) per minute shall not exceed 25 millimeters (1 inch) of water.