{"data":{"id":"us/30-cfr-7.502","jurisdiction":"us","citation":"30 CFR 7.502","heading":"Definitions.","body":"The following definitions apply in this subpart:\nApparent temperature. A measure of relative discomfort due to the combined effects of air movement, heat, and humidity on the human body.\nBreathable oxygen. Oxygen that is at least 99 percent pure with no harmful contaminants.\nFlash fire. A fire that rapidly spreads through a diffuse fuel, such as airborne coal dust or methane, without producing damaging pressure.\nNoncombustible material. Material, such as concrete or steel, that will not ignite, burn, support combustion, or release flammable vapors when subjected to fire or heat.\nOverpressure. The highest pressure over the background atmospheric pressure that could result from an explosion, which includes the impact of the pressure wave on an object.\nRefuge alternative. A protected, secure space with an isolated atmosphere and integrated components that create a life-sustaining environment for persons trapped in an underground coal mine.","path":["Title 30—Mineral Resources","CHAPTER I—MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR","SUBCHAPTER B—TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS","PART 7—TESTING BY APPLICANT OR THIRD PARTY","Subpart L—Refuge Alternatives"],"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":"0e17fbf2ef301c374d264f203ba5127cb65699a003bfa79333737e2690ab2194","source_id":"us-cfr","stale":true,"prev":"us/30-cfr-7.501","next":"us/30-cfr-7.503"},"notice":"GroundRules: Original legal text. Not legal advice."}