{
  "schema": "piping-protection-methods/v1",
  "chapter": "C15",
  "methods": [
    {
      "id": "paint-application-screen",
      "classification": "Scoped application criteria with hypothetical measured conditions",
      "formula": "M = T_surface - T_dew",
      "units": {
        "T_surface": "degC",
        "T_dew": "degC",
        "M": "degC temperature difference",
        "relative_humidity": "percent"
      },
      "criteria_under_this_paint_route": {
        "minimum_margin_degC": 3,
        "margin_operator": ">=",
        "maximum_relative_humidity_percent": 85,
        "humidity_operator": "<="
      },
      "other_conditions": [
        "Actual product/mixing/application/recoat method",
        "Surface cleanliness and dryness",
        "Specified maximum surface temperature with manufacturer exception",
        "Specified minimum air temperature with local conditions",
        "Unfavorable weather changes within stated period",
        "Required lighting and absence of rain/condensation/frost"
      ],
      "exceptions": "Only explicit agreed local-condition provision of this adopted route; other blasting routes can use strict >3C instead",
      "cases": [
        {
          "hypothetical_T_dew_degC": 14,
          "hypothetical_T_surface_degC": 16,
          "hypothetical_RH_percent": 70,
          "margin_degC": 2,
          "meets_two_screening_conditions": false
        },
        {
          "hypothetical_T_dew_degC": 14,
          "hypothetical_T_surface_degC": 19,
          "hypothetical_RH_percent": 70,
          "margin_degC": 5,
          "meets_two_screening_conditions": true
        }
      ],
      "acceptance": "Passing these two conditions does not release paint application"
    },
    {
      "id": "polyolefin-thickness-selection",
      "classification": "Particular qualified PE/PP system schedule, not universal polymer coating minima",
      "DN_definition": "Nominal diameter designation; not measured bore/OD or wall",
      "thickness_units": "mm total coating",
      "example": {
        "hypothetical_DN": 300,
        "selected_PE_min_total_mm": 2.9,
        "selected_PP_min_total_mm": 2.2
      },
      "boundary_example": {
        "DN": 500,
        "PE_min_total_mm": 3.2,
        "PP_min_total_mm": 2.5
      },
      "conditions": [
        "Complete layer/material/application/qualification basis required",
        "Primer and adhesive thickness set separately by application procedure",
        "Mechanical/temperature/adhesion/ageing/cathodic-disbonding tests remain separate",
        "Lower total is not a substitution or superiority conclusion"
      ]
    },
    {
      "id": "spent-acid-entry-screen",
      "classification": "Specified wet-sour pipeline flowback route with hypothetical reported samples",
      "predicate": "pH >= 4 AND chloride_reported_ppm <= 50000",
      "units": {
        "pH": "dimensionless reported analytical pH",
        "chloride_reported_ppm": "ppm as reported under the adopted sampling/analysis basis"
      },
      "cases": [
        {
          "hypothetical_pH": 3.8,
          "hypothetical_chloride_reported_ppm": 40000,
          "meets_two_entry_conditions": false,
          "limiting_condition": "pH"
        },
        {
          "hypothetical_pH": 4.5,
          "hypothetical_chloride_reported_ppm": 60000,
          "meets_two_entry_conditions": false,
          "limiting_condition": "chloride"
        },
        {
          "hypothetical_pH": 4.5,
          "hypothetical_chloride_reported_ppm": 40000,
          "meets_two_entry_conditions": true,
          "limiting_condition": "No failure of these two conditions; other conditions remain"
        }
      ],
      "conditions": [
        "Temporary separation/separate liquids disposal until both met",
        "Retain sampling/analysis concentration basis; do not silently invent ppm mass/volume conversion",
        "Required startup/enhanced mitigation and observation follow entry",
        "Unknown chemistry/solids/material cracking/steady-state eligibility not established"
      ],
      "acceptance": "Only the stated conjunctive entry screen; not universal acid/pipeline permission"
    }
  ]
}