CFR›Title 30›Chapter I›Part 27 ContainsSubparts A–CCorpusDaily eCFRDisplayed edition2026-04-15Last updated2026-04-15 PART 27—METHANE-MONITORING SYSTEMS Subparts A Subpart A—General Provisions Sections 27.1–27.12 B Subpart B—Construction and Design Requirements Sections 27.20–27.24 C Subpart C—Test Requirements Sections 27.30–27.41 Authority30 U.S.C. 957, 961.Source31 FR 10607, Aug. 9, 1966, unless otherwise noted. Previous 23 Part 23—Telephones and Signaling Devices Next 28 Part 28—Fuses for Use with Direct Current in Providing Short-Circuit Protection for Trailing Cables in Coal Mines