30 C.F.R. § 27.22 Methane detector component.
Title 30 - Mineral Resources
(a) A methane detector component shall be suitably constructed for incorporation in or with permissible and approved equipment that is operated in gassy mines and tunnels. (b) A methane detector shall include: (1) A method of continuous sampling of the atmosphere in which it functions. (2) A method for actuating a warning device which shall function automatically at a methane content of the mine atmosphere between 1.0 to 1.5 volume percent. The warning device shall also function automatically at all higher concentrations of methane in the mine atmosphere. (3) A method for actuating a power-shutoff component, which shall function automatically when the methane content of the mine atmosphere is 2.0 volume percent and at all higher concentrations of methane. (4) A suitable filter on the sampling intake to prevent dust and moisture from entering and interfering with normal operation. Note: This requirement for the methane detector may be waived if the design is such as to preclude the need of a filter. (c) A methane detector may provide means for sampling at more than one point; provided, the methane detector shall separately detect the methane in the atmosphere at each sampling point with, in MSHA's opinion, sufficient frequency.
Title 30: Mineral Resources
PART 27—METHANE-MONITORING SYSTEMS
Subpart B—Construction and Design Requirements
§ 27.22 Methane detector component.

