CFR > Title 30 - Mineral Resources > CHAPTER I—MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR > SUBCHAPTER B—TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS (parts 5 to 36) > PART 27—METHANE-MONITORING SYSTEMS > SUBPART B—Construction and Design Requirements (§27.20 to §27.24) > 27.22—Methane detector component.

27.22—Methane detector component.

(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.

Code of Federal Regulations

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.