{
  "object_id": "c03-gas-decompression",
  "title": "Gas-loaded soft seals: mechanism, reported histories and qualification",
  "mechanism": [
    "Pressurized gas is absorbed within an elastomer.",
    "External pressure falls; absorbed gas expands.",
    "Swelling,blisters and cracks can damage the sealing section."
  ],
  "mechanism_scope": "Physical decompression damage; chemical attack/aging may coexist. No kinetics or life-prediction model.",
  "susceptibility_observation": {
    "cross_section_diameter": {
      "value": 0.15,
      "unit": "in",
      "equivalent_mm": 3.81
    },
    "direction": "Larger sections and dynamic seals generally more susceptible in reported comparison.",
    "limits": "Cross-section thickness, not whole-ring outside diameter; no immunity below size, no universal prohibition above."
  },
  "assembly_variables": [
    "actual formulation,cure,hardness",
    "seal section and movement",
    "confinement,clearances,extrusion pathways",
    "fluid composition and established partial-pressure basis",
    "high/low temperature and pressure",
    "pressure-versus-time trace and cycle history",
    "inspection and replacement history"
  ],
  "reported_histories": [
    {
      "case_id": "history-1",
      "duty": "Oil production",
      "reported_pressure": {
        "value": 4000,
        "unit": "psi",
        "reference": null
      },
      "reported_CO2": {
        "value": 12,
        "unit": "percent",
        "basis": null
      },
      "reported_temperature": {
        "value": 200,
        "unit": "degF"
      },
      "observation": "Very few incidents, not zero.",
      "decision_distinction": "Fluid and operating history matter; no all-oil immunity.",
      "acceptance_status": "Reported history, not a design limit or qualification of another assembly."
    },
    {
      "case_id": "history-2",
      "duty": "Gas injection",
      "reported_pressure": {
        "value": 4000,
        "unit": "psi",
        "reference": null
      },
      "reported_CO2": {
        "value": 12,
        "unit": "percent",
        "basis": null
      },
      "reported_temperature": {
        "value": 300,
        "unit": "degF"
      },
      "observation": "70-durometer fluoroelastomer compressor seals failed;90-durometer formulation of that family or another reported fluoroelastomer satisfactory WITH periodic replacement.",
      "decision_distinction": "Preserve actual compound,equipment,temperature and maintained replacement basis; scale and interval unknown.",
      "acceptance_status": "Reported history, not a design limit or qualification of another assembly."
    },
    {
      "case_id": "history-3",
      "duty": "CO2 production,pipelines,injection",
      "reported_pressure": {
        "value": 1800,
        "unit": "psi",
        "reference": null
      },
      "reported_CO2": {
        "value": 98,
        "unit": "percent",
        "basis": null
      },
      "reported_temperature": {
        "value": 100,
        "unit": "degF"
      },
      "observation": "Several elastomer families failed in some equipment while same families worked in other equipment under reported conditions.",
      "decision_distinction": "Family identity does not establish assembly/formulation qualification.",
      "acceptance_status": "Reported history, not a design limit or qualification of another assembly."
    },
    {
      "case_id": "history-4",
      "duty": "CO2 pipelines",
      "reported_pressure": {
        "value": 3000,
        "unit": "psi",
        "reference": null
      },
      "reported_CO2": {
        "value": 98,
        "unit": "percent",
        "basis": null
      },
      "reported_temperature": {
        "value": 100,
        "unit": "degF"
      },
      "observation": "Failures across listed families; some peroxide-cured compounds successful, largely assembly dependent.",
      "decision_distinction": "Cure and assembly belong to the history, not a family-wide approval.",
      "acceptance_status": "Reported history, not a design limit or qualification of another assembly."
    },
    {
      "case_id": "history-5",
      "duty": "Hot CO2 handling",
      "reported_pressure": {
        "value": 4500,
        "unit": "psi",
        "reference": null
      },
      "reported_CO2": {
        "value": 98,
        "unit": "percent",
        "basis": null
      },
      "reported_temperature": {
        "value": 350,
        "unit": "degF"
      },
      "observation": "Reported as technology-edge research duty at time of report.",
      "decision_distinction": "Historical uncertainty, not a present universal limit.",
      "acceptance_status": "Reported history, not a design limit or qualification of another assembly."
    }
  ],
  "pressure_fall_descriptor": {
    "formula": "r=(p_H-p_L)/Delta_t",
    "quantities": {
      "p_H": "High pressure, same reference and units as p_L",
      "p_L": "Low pressure, same reference and units as p_H",
      "Delta_t": "Elapsed time, positive",
      "r": "Average positive pressure-fall magnitude; not complete pressure trace"
    },
    "comparisons": [
      {
        "drop_psi": 1000,
        "elapsed_min": 1440,
        "average_psi_per_min": 0.6944444444444444
      },
      {
        "drop_psi": 1000,
        "elapsed_min": 10,
        "average_psi_per_min": 100
      }
    ],
    "rate_ratio": 144,
    "scope": "Reported magnitudes illustrate time definition only; no recommended ramp, safe rate, failure threshold or acceptance window."
  },
  "qualification_steps": [
    "Define actual environment and decompression histories, retaining unknown inputs.",
    "Identify actual compound and installed assembly; check other simultaneous chemical/thermal/friction/wear duties.",
    "Verify comparable equipment operating history including replacement.",
    "For materially new environment/equipment, establish decompression tests on actual equipment before committing selection; criteria separately established.",
    "Preserve qualified configuration,conditions,inspection and replacement basis through procurement,operation and change."
  ],
  "unresolved_inputs": [
    "pressure gauge/absolute reference",
    "percentage composition basis",
    "universal safe CO2 partial pressure",
    "durometer scale",
    "specific compound formulation/cure for every history",
    "depressurization acceptance criterion",
    "replacement interval",
    "safe cycle count"
  ],
  "not_derived": [
    "No partial pressure computed from percentage times unspecified pressure.",
    "600psi wording does not establish zero risk.",
    "Sensitivity groups do not establish a universal family ranking.",
    "Reported hot-duty research status is not a current technology limit."
  ]
}