---
kind: "section"
citation: "42 C.F.R. § 84.70"
title: "42"
number: "84.70"
heading: "Self-contained breathing apparatus; description."
url: "https://uscodex.org/cfr/42/84.70"
---

# §84.70. Self-contained breathing apparatus; description.

- (a) Self-contained breathing apparatus, including all completely assembled, portable, self-contained devices designed for use as respiratory protection during entry into and escape from or escape only from hazardous atmospheres, are described as follows:
  - (1) **Closed-circuit apparatus.** An apparatus of the type in which the exhalation is rebreathed by the wearer after the carbon dioxide has been effectively removed and a suitable oxygen concentration restored from sources composed of:
    - (i) Compressed oxygen; or
    - (ii) Chemical oxygen; or
    - (iii) **Liquid-oxygen.**
  - (2) **Open-circuit apparatus.** An apparatus of the following types from which exhalation is vented to the atmosphere and not rebreathed:
    - (i) **Demand-type apparatus.** An apparatus in which the pressure inside the facepiece in relation to the immediate environment is positive during exhalation and negative during inhalation; or
    - (ii) **Pressure-demand-type apparatus.** An apparatus in which the pressure inside the facepiece in relation to the immediate environment is positive during both inhalation and exhalation.
- (b) The following respirators may be classified as designed and approved for use during emergency entry into a hazardous atmosphere:
  - (1) A combination respirator which includes a self-contained breathing apparatus; and
  - (2) **A Type “C” or Type “CE” supplied air respirator, where—**
    - (i) The self-contained breathing apparatus is classified for 3-, 5-, or 10-minute service time and the air line supply is used during entry; or
    - (ii) The self-contained breathing apparatus is classified for 15 minutes or longer service time and not more than 20 percent of the rated capacity of the air supply is used during entry.
- (c) Self-contained breathing apparatus classified for less than 1 hour service time will not be approved for use during underground mine rescue and recovery operations except as auxiliary equipment.
- (d) Self-contained breathing apparatus classified for less than 30 minutes' service time will not be approved for use as auxiliary equipment during underground mine rescue and recovery operations.

## Notes

### Amendments

[60 FR 30355, June 8, 1995, as amended at 77 FR 14193, Mar. 8, 2012; 84 FR 16412, Apr. 19, 2019]

### Authority

Authority: 29 U.S.C. 651 et seq.; 30 U.S.C. 3, 5, 7, 811, 842(h), 844.

### Source

Source: 60 FR 30355, June 8, 1995, unless otherwise noted.

### Amendments

[60 FR 30355, June 8, 1995, as amended at 77 FR 14193, Mar. 8, 2012; 84 FR 16412, Apr. 19, 2019]