Absolute Pressure

{
  "id": "MLC-T-ENV-000151",
  "term": "Absolute Pressure",
  "field": "Environment",
  "definition": "1. Absolute pressure refers to the total pressure exerted on a surface. The more usual pressure measured by most gauges is called \"gauge pressure\" and reflects an adjusted pressure that measures zero at the earth's surface. Since atmospheric pressure at the earth's surface is 14.7 pounds per square inch (psi), the absolute pressure is 14.7 psi higher than gauge pressure at the same location. Maximum injection pressure is fundamentally calculated as an absolute pressure and must therefore be corrected to gauge pressures by subtracting 14.7 psi, since this is the pressure measured by most gauges.\n\n2. Pressure scale that starts with a value of zero for an absolute vacuum.\n\n3. Pressure measured with reference to absolute zero pressure, usually expressed in units of kilopascal (kPa) absolute or pounds per square inch absolute (psia).",
  "subject": "Land, waste and cleanup",
  "references": [
    "Underground Injection Control Terms",
    "Basic Concepts in Environmental Sciences",
    "40 CFR Appendix A to Part 63 (CFR 2024)"
  ],
  "url": "https://mlchart.com/terminology/environment/absolute-pressure/"
}