[Code of Federal Regulations] [Title 30, Volume 1] [Revised as of July 1, 2002] From the U.S. Government Printing Office via GPO Access [CITE: 30CFR57.4160] [Page 323] TITLE 30--MINERAL RESOURCES CHAPTER I--MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR PART 57--SAFETY AND HEALTH STANDARDS--UNDERGROUND METAL AND NONMETAL MINES--Table of Contents Subpart C--Fire Prevention and Control Sec. 57.4160 Underground electric substations and liquid storage facilities. The requirements of this standard apply to underground areas only. (a) Areas within 25 feet of the following shall be free of combustible materials: (1) Electric substations. (2) Unburied, combustible liquid storage tanks. (3) Any group of containers used for storage of more than 60 gallons of combustible liquids. (b) This standard does not apply to installed wiring or timber that is coated with at least one inch of shotcrete, one-half inch of gunite, or other noncombustible materials with equivalent fire protection characteristics.