---
kind: "section"
citation: "30 C.F.R. § 7.507"
title: "30"
number: "7.507"
heading: "Air-monitoring components."
url: "https://uscodex.org/cfr/30/7.507"
---

# §7.507. Air-monitoring components.

- (a) Each refuge alternative shall have an air-monitoring component that provides persons inside with the ability to determine the concentrations of carbon dioxide, carbon monoxide, oxygen, and methane, inside and outside the structure, including the airlock.
- (b) Refuge alternatives designed for use in mines with a history of harmful gases, other than carbon monoxide, carbon dioxide, and methane, shall be equipped to measure the harmful gases' concentrations.
- (c) The air-monitoring component shall be inspected or tested and the test results shall be included in the application.
- (d) The air-monitoring component shall meet the following:
  - (1) The total measurement error, including the cross-sensitivity to other gases, shall not exceed ±10 percent of the reading, except as specified in the approval.
  - (2) The measurement error limits shall not be exceeded after start-up, after 8 hours of continuous operation, after 96 hours of storage, and after exposure to atmospheres with a carbon monoxide concentration of 999 ppm (full-scale), a carbon dioxide concentration of 3 percent, and full-scale concentrations of other gases.
  - (3) Calibration gas values shall be traceable to the National Institute for Standards and Technology (NIST) “Standard Reference Materials” (SRMs).
  - (4) The analytical accuracy of the calibration gas and span gas values shall be within 2.0 percent of NIST gas standards.
  - (5) The detectors shall be capable of being kept fully charged and ready for immediate use.

## Notes

### Source

Source: 74 FR 80694, Dec. 31, 2008, unless otherwise noted.

### Authority

Authority: 30 U.S.C. 957.

### Source

Source: 53 FR 23500, June 22, 1988, unless otherwise noted.