{
  "schema": "native-teaching-figure/v1",
  "anchor": "c20-online-wall-coverage",
  "location_basis": [
    "actual tie-in center",
    "proposed attachment weld perimeter",
    "final fitting location"
  ],
  "general_grid": {
    "spacing": "not dimensioned",
    "drawn_points": "illustrative; no required count inferred"
  },
  "weld_line_sampling": {
    "selected_spacing": 2,
    "unit": "in",
    "direction": "along actual weld perimeter on curved run surface"
  },
  "separate_full_preweld_region": {
    "extent": "weld area plus3in either side",
    "methods": [
      "MT",
      "PT for nonmagnetic material",
      "UT defects/laminations"
    ],
    "not_equivalent": "grid or weldline thickness sampling alone"
  },
  "downstream_inputs": [
    "evaluated minimum actual wall",
    "local defects/laminations",
    "pipe ovality",
    "nearby welds",
    "material/pressure/thermal weakening",
    "machine and branch loads"
  ],
  "examination_stage_context": {
    "root_cap": "selected surface examinations",
    "hardness": "weld and HAZ",
    "delayed": "normally48h under selected method, qualified metallurgical adjustment only"
  },
  "qualified_coverage": [
    "material",
    "curvature",
    "surface",
    "probe/coupling",
    "calibration",
    "sound path",
    "coverage",
    "acceptance",
    "personnel"
  ],
  "point_count_claim": "none"
}