{
  "ftaDoc": {
    "version": "5.0",
    "standard": "IEC61025",
    "savedAt": "2026-03-10T03:38:07.485650Z"
  },
  "projects": [
    {
      "id": "p8548cc9e",
      "name": "Process \u2014 Pressure Vessel",
      "expanded": true,
      "settings": {
        "description": "Fault tree for catastrophic failure of a process pressure vessel. Based on HAZOP study output addressing overpressure, structural degradation and high-temperature scenarios. SIL 2 target for safety instrumented system protection layer per IEC 61508/61511.",
        "organization": "FTA Studio Template Library",
        "analyst": "",
        "revision": "A",
        "standard": "IEC61025",
        "silTarget": "SIL2",
        "missionTime": 8760,
        "anaMethod": "exact",
        "sciNotation": true
      },
      "ftas": [
        {
          "id": "f96bfa920",
          "name": "Pressure Vessel Catastrophic Rupture",
          "nodes": [
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              "id": "n7acf7727",
              "uid": "TOP-001",
              "ntype": "top",
              "gateType": "OR",
              "name": "Pressure Vessel Catastrophic Rupture",
              "desc": "Sudden uncontrolled failure of pressurised vessel resulting in explosion/loss of containment. Ref: IEC 61508, HAZOP study output. SIL 2 target for SIS protection layer.",
              "outputId": null,
              "refId": null,
              "prob": null,
              "lambda": null,
              "mu": null,
              "missionTime": 8760,
              "sil": null,
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              "occurrence": null,
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              "x": 640.0,
              "y": 80
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            {
              "id": "n63452cda",
              "uid": "G-001",
              "ntype": "gate",
              "gateType": "AND",
              "name": "Overpressure Rupture",
              "desc": "Vessel operates above design pressure AND all pressure relief fails.",
              "outputId": "n7acf7727",
              "refId": null,
              "prob": null,
              "lambda": null,
              "mu": null,
              "missionTime": 8760,
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              "y": 250
            },
            {
              "id": "naaa28f5b",
              "uid": "G-002",
              "ntype": "gate",
              "gateType": "OR",
              "name": "Excessive Pressure Initiating Event",
              "desc": "Initiating cause of overpressure condition.",
              "outputId": "n63452cda",
              "refId": null,
              "prob": null,
              "lambda": null,
              "mu": null,
              "missionTime": 8760,
              "sil": null,
              "failureMode": "",
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              "hazards": [],
              "evidence": "",
              "mitigation": "",
              "severity": null,
              "occurrence": null,
              "detectability": null,
              "x": -60.0,
              "y": 420
            },
            {
              "id": "n510db269",
              "uid": "BE-001",
              "ntype": "basic",
              "gateType": null,
              "name": "Feed control valve fails fully open",
              "desc": "Process control valve fails in open position \u2014 actuator or positioner failure.",
              "outputId": "naaa28f5b",
              "refId": null,
              "prob": null,
              "lambda": 3e-05,
              "mu": null,
              "missionTime": 8760,
              "sil": null,
              "failureMode": "Uncontrolled feed flow",
              "detection": "Flow transmitter high alarm",
              "hazards": [],
              "evidence": "",
              "mitigation": "SIS high-high flow shutdown",
              "severity": null,
              "occurrence": null,
              "detectability": null,
              "x": -220.0,
              "y": 590
            },
            {
              "id": "n7d7a3900",
              "uid": "BE-002",
              "ntype": "basic",
              "gateType": null,
              "name": "Cooling system failure \u2014 exothermic runaway",
              "desc": "Loss of reaction cooling allowing exothermic runaway pressure generation.",
              "outputId": "naaa28f5b",
              "refId": null,
              "prob": null,
              "lambda": 1e-06,
              "mu": null,
              "missionTime": 8760,
              "sil": null,
              "failureMode": "Reaction rate exceedance",
              "detection": "Temperature high-high alarm, calorimetry monitoring",
              "hazards": [],
              "evidence": "",
              "mitigation": "Dump quench system; inhibitor injection SIS",
              "severity": null,
              "occurrence": null,
              "detectability": null,
              "x": -60.0,
              "y": 590
            },
            {
              "id": "nc3e54a02",
              "uid": "BE-003",
              "ntype": "basic",
              "gateType": null,
              "name": "Blocked outlet \u2014 downstream valve closed",
              "desc": "Downstream isolation valve incorrectly closed with flow continuing.",
              "outputId": "naaa28f5b",
              "refId": null,
              "prob": null,
              "lambda": 5e-06,
              "mu": null,
              "missionTime": 8760,
              "sil": null,
              "failureMode": "No pressure relief path",
              "detection": "Pressure rise alarm, valve position indication",
              "hazards": [],
              "evidence": "",
              "mitigation": "Administrative control + valve interlock on outlet",
              "severity": null,
              "occurrence": null,
              "detectability": null,
              "x": 100.0,
              "y": 590
            },
            {
              "id": "n2a636d29",
              "uid": "G-003",
              "ntype": "gate",
              "gateType": "AND",
              "name": "All Pressure Relief Fails",
              "desc": "Both primary and secondary relief devices must fail to open.",
              "outputId": "n63452cda",
              "refId": null,
              "prob": null,
              "lambda": null,
              "mu": null,
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              "x": 340.0,
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            },
            {
              "id": "naf35afc1",
              "uid": "BE-004",
              "ntype": "basic",
              "gateType": null,
              "name": "Primary pressure relief valve fails to open",
              "desc": "Spring-loaded PRV fails to lift at set pressure \u2014 corrosion, deposits or fatigue.",
              "outputId": "n2a636d29",
              "refId": null,
              "prob": null,
              "lambda": 5e-06,
              "mu": null,
              "missionTime": 8760,
              "sil": null,
              "failureMode": "No relief at set pressure",
              "detection": "Periodic proof test (annually)",
              "hazards": [],
              "evidence": "",
              "mitigation": "Secondary relief valve; redundant SIS shutdown",
              "severity": null,
              "occurrence": null,
              "detectability": null,
              "x": 260.0,
              "y": 590
            },
            {
              "id": "n4649df89",
              "uid": "BE-005",
              "ntype": "basic",
              "gateType": null,
              "name": "Secondary pressure relief valve fails to open",
              "desc": "Backup PRV fails to open \u2014 physically separate from primary device.",
              "outputId": "n2a636d29",
              "refId": null,
              "prob": null,
              "lambda": 5e-06,
              "mu": null,
              "missionTime": 8760,
              "sil": null,
              "failureMode": "Backup relief unavailable",
              "detection": "Annual proof test; independent of primary PRV",
              "hazards": [],
              "evidence": "",
              "mitigation": "SIS pressure shutdown as independent protection layer",
              "severity": null,
              "occurrence": null,
              "detectability": null,
              "x": 420.0,
              "y": 590
            },
            {
              "id": "ne52481be",
              "uid": "G-004",
              "ntype": "gate",
              "gateType": "OR",
              "name": "Vessel Structural Integrity Failure",
              "desc": "Failure of vessel shell below design pressure \u2014 degradation mechanisms.",
              "outputId": "n7acf7727",
              "refId": null,
              "prob": null,
              "lambda": null,
              "mu": null,
              "missionTime": 8760,
              "sil": null,
              "failureMode": "",
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              "hazards": [],
              "evidence": "",
              "mitigation": "",
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              "occurrence": null,
              "detectability": null,
              "x": 740.0,
              "y": 250
            },
            {
              "id": "ndd72f2e3",
              "uid": "BE-006",
              "ntype": "basic",
              "gateType": null,
              "name": "External corrosion \u2014 wall thinning below minimum",
              "desc": "Progressive external corrosion reducing wall thickness to failure.",
              "outputId": "ne52481be",
              "refId": null,
              "prob": null,
              "lambda": 2e-06,
              "mu": null,
              "missionTime": 8760,
              "sil": null,
              "failureMode": "Wall perforation or rupture at normal pressure",
              "detection": "Periodic UT thickness inspection",
              "hazards": [],
              "evidence": "",
              "mitigation": "External coating + cathodic protection; inspection schedule per API 510",
              "severity": null,
              "occurrence": null,
              "detectability": null,
              "x": 580.0,
              "y": 420
            },
            {
              "id": "n95edd4bf",
              "uid": "BE-007",
              "ntype": "basic",
              "gateType": null,
              "name": "Weld defect propagation \u2014 fatigue crack",
              "desc": "Pre-existing or in-service weld crack propagating to critical length under cyclic loading.",
              "outputId": "ne52481be",
              "refId": null,
              "prob": null,
              "lambda": 5e-07,
              "mu": null,
              "missionTime": 8760,
              "sil": null,
              "failureMode": "Fracture at weld seam",
              "detection": "Magnetic particle inspection, AE monitoring",
              "hazards": [],
              "evidence": "",
              "mitigation": "PWHT; NDT on all welds at fabrication and inspection intervals",
              "severity": null,
              "occurrence": null,
              "detectability": null,
              "x": 740.0,
              "y": 420
            },
            {
              "id": "n3ec99ff0",
              "uid": "BE-008",
              "ntype": "basic",
              "gateType": null,
              "name": "Stress corrosion cracking (SCC)",
              "desc": "SCC in susceptible material (e.g. AISI 304 in chloride service).",
              "outputId": "ne52481be",
              "refId": null,
              "prob": null,
              "lambda": 1e-06,
              "mu": null,
              "missionTime": 8760,
              "sil": null,
              "failureMode": "Brittle fracture without warning",
              "detection": "ACFM inspection, hydrogen monitoring",
              "hazards": [],
              "evidence": "",
              "mitigation": "Material selection; process chemistry control (H2S limits)",
              "severity": null,
              "occurrence": null,
              "detectability": null,
              "x": 900.0,
              "y": 420
            },
            {
              "id": "n63831f44",
              "uid": "G-005",
              "ntype": "gate",
              "gateType": "AND",
              "name": "High Temperature Vessel Damage",
              "desc": "Temperature exceedance AND temperature protection failure leading to creep/rupture.",
              "outputId": "n7acf7727",
              "refId": null,
              "prob": null,
              "lambda": null,
              "mu": null,
              "missionTime": 8760,
              "sil": null,
              "failureMode": "",
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              "hazards": [],
              "evidence": "",
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              "severity": null,
              "occurrence": null,
              "detectability": null,
              "x": 1140.0,
              "y": 250
            },
            {
              "id": "n229ec409",
              "uid": "BE-009",
              "ntype": "basic",
              "gateType": null,
              "name": "Cooling jacket failure \u2014 loss of coolant flow",
              "desc": "Loss of cooling water to vessel jacket \u2014 pump trip or valve closure.",
              "outputId": "n63831f44",
              "refId": null,
              "prob": null,
              "lambda": 2e-05,
              "mu": null,
              "missionTime": 8760,
              "sil": null,
              "failureMode": "Vessel temperature above design limit",
              "detection": "Outlet temperature alarm, flow switch",
              "hazards": [],
              "evidence": "",
              "mitigation": "Cooling flow interlock; backup cooling circuit",
              "severity": null,
              "occurrence": null,
              "detectability": null,
              "x": 1060.0,
              "y": 420
            },
            {
              "id": "nb7b9803f",
              "uid": "BE-010",
              "ntype": "basic",
              "gateType": null,
              "name": "Temperature SIS fails to initiate shutdown",
              "desc": "Safety Instrumented System fails to trip process on high-high temperature detection.",
              "outputId": "n63831f44",
              "refId": null,
              "prob": null,
              "lambda": 5e-06,
              "mu": null,
              "missionTime": 8760,
              "sil": null,
              "failureMode": "No shutdown on high-high temperature",
              "detection": "SIL assessment proof test (per IEC 61511)",
              "hazards": [],
              "evidence": "",
              "mitigation": "Redundant temperature sensors (2oo3 voting); SIL 2 SIS design",
              "severity": null,
              "occurrence": null,
              "detectability": null,
              "x": 1220.0,
              "y": 420
            }
          ],
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            "zoom": 0.72
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      ],
      "eventLibrary": []
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  ],
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}