Relief valve

{
  "id": "MLC-T-ENV-023732",
  "term": "Relief valve",
  "field": "Environment",
  "term_source": "Relief Valve",
  "definition": "1. Valve used only to release an unplanned, nonroutine discharge. A relief valve discharge results from an operator error, a malfunction such as a power failure or equipment failure, or other unexpected cause that requires immediate venting of gas from process equipment in order to avoid safety hazards or equipment damage.\n\n2. Each pressure relief device including pressure relief valves, rupture disks and other pressure relief systems used to protect process components from overpressure conditions. “Relief valve” does not include polymerization shortstop systems, referigerated water systems or control valves or other devices used to control flow to an incinerator or other air pollution control device.\n\n3. Valve used only to release an unplanned, nonroutine discharge. A relief valve discharge can result from an operator error, a malfunction such as a power failure or equipment failure, or other unexpected cause that requires immediate venting of gas from process equipment in order to avoid safety hazards or equipment damage.\n\n4. Device or valve used only to release an unplanned, nonroutine discharge. A relief device or valve discharge can result from an operator error, a malfunction such as a power failure or equipment failure, or other unexpected cause that requires immediate venting of gas from process equipment in order to avoid safety hazards or equipment damage.\n\n5. Type of pressure relief device that is designed to re-close after the pressure relief.\n\n6. Combustion device or recapture device used to reduce organic hazardous air pollutant emissions by 98 percent, or to an outlet concentration of 20 parts per million by volume.",
  "subject": "Built environments",
  "references": [
    "40 CFR 60.701 (CFR 2013); 40 CFR 60.611a (CFR 2024)",
    "40 CFR 61.61 (CFR 2013)",
    "40 CFR 63.1001 (CFR 2013); 40 CFR 63.1020 (CFR 2013)",
    "40 CFR 65.2 (CFR 2013)",
    "40 CFR 63.641 (CFR 2019); 85 FR 40386; 40 CFR 63.1103 (CFR 2021); 85 FR 40740; 40 CFR 63.2406 (CFR 2021); 85 FR 49084; 40 CFR 63.255 (CFR 2021)",
    "40 CFR 63.101 (CFR 2024)"
  ],
  "url": "https://mlchart.com/terminology/environment/relief-valve/"
}