{
  "schema": "native-teaching-figure/v1",
  "anchor": "c17-seal-bridge-root",
  "scale": "schematic",
  "material_key": {
    "gray_hatch": "component material",
    "blue": "deposited weld"
  },
  "seal": {
    "duty": [
      "exposed thread notch coverage",
      "leak path closure"
    ],
    "coverage": [
      "all exposed threads",
      "thread runout scratches",
      "entire fitting face"
    ],
    "contour": [
      "flat",
      "slightly concave"
    ],
    "excluded_contour": "convex",
    "undercut": "none in selected detail",
    "makeup": "dry, no thread compound or PTFE tape, proper engagement"
  },
  "bridge": {
    "service": "selected severe cyclic service",
    "alternatives": [
      "short separate nipple and socket-welding or threaded valve",
      "integral male-ended valve"
    ],
    "nipple_extent": "full nipple length to full valve-hub diameter",
    "depicted_run_minimum": {
      "value": 2,
      "unit": "in",
      "status": "selected depicted condition, not generic permission"
    },
    "local_remaining_spacing": {
      "operator": "<",
      "value": 0.25,
      "unit": "in",
      "consequence": "selected bridge instruction to avoid notch",
      "distinct_from": "full nipple length L"
    }
  },
  "separate_interfaces": [
    "run-to-fitting attachment",
    "fitting-to-root engagement",
    "root-to-valve engagement or integral male end",
    "valve internals"
  ],
  "not_established": [
    "full-strength weld qualification",
    "fatigue rating",
    "pressure adequacy",
    "generic application to every short nipple"
  ]
}