---
kind: "section"
citation: "30 C.F.R. § 27.23"
title: "30"
number: "27.23"
heading: "Automatic warning device."
url: "https://uscodex.org/cfr/30/27.23"
---

# §27.23. Automatic warning device.

- (a) An automatic warning device shall be suitably constructed for incorporation in or with permissible and approved equipment that is operated in gassy mines and tunnels.
- (b) An automatic warning device shall include an alarm signal (audible or colored light), which shall be made to function automatically at a methane content of the mine atmosphere between 1.0 to 1.5 volume percent and at all higher concentrations of methane.
- (c) It is recommended that the automatic warning device be supplemented by a meter calibrated in volume percent of methane.

## Notes

### Authority

Authority: 30 U.S.C. 957, 961.

### Source

Source: 31 FR 10607, Aug. 9, 1966, unless otherwise noted.