{"data":{"id":"us/30-cfr-57.4504","jurisdiction":"us","citation":"30 CFR 57.4504","heading":"Fan installations.","body":"(a) Fan houses, fan bulkheads for main and booster fans, and air ducts connecting main fans to underground openings shall be constructed of noncombustible materials.\n(b) Areas within 25 feet of main fans or booster fans shall be free of combustible materials, except installed wiring, ground and track support, headframes, and direct-fired heaters. Other timber shall be coated with one inch of shotcrete, one-half inch of gunite, or other noncombustible materials.","path":["Title 30—Mineral Resources","CHAPTER I—MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR","SUBCHAPTER K—METAL AND NONMETAL MINE SAFETY AND HEALTH","PART 57—SAFETY AND HEALTH STANDARDS—UNDERGROUND METAL AND NONMETAL MINES","Subpart C—Fire Prevention and Control"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-30.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:25:24Z","sha256":"41421c486b8371be530caeeabdbc792cb594a6f68f2714aa278645d0b42ede4d","source_id":"us-cfr","stale":true,"prev":"us/30-cfr-57.4503","next":"us/30-cfr-57.4505"},"notice":"GroundRules: Original legal text. Not legal advice."}