UV Index Exposure Time Estimator implementation

Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

Record owner

Guth Instruments

Lifecycle

verified-clean

Evidence ID

t7-080

Effect

Computation or source lookup only

Input and validation requirements

UV_index = 0 causes division by zero and must be rejected. Additionally, the required Fitzpatrick MED/skin-factor lookup table and output time unit are absent from the specification, so numerical results are conditional on assumed factors and a minutes convention.

Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

{
  "inputs": {
    "uv_index": 1,
    "fitzpatrick_skin_type": "I"
  },
  "expected_outputs": {
    "estimated_time_to_erythema_minutes": 200,
    "estimated_time_to_erythema_seconds": 12000
  },
  "reference_data": {
    "skin_type": "I",
    "MED_J_per_m2": 200,
    "skin_factor_relative_to_type_I": 1,
    "rule_of_thumb_base_minutes": 200,
    "source_convention": "MED value: widely tabulated standard Fitzpatrick educational convention; rule-of-thumb base: instrument-stated heuristic, not a medical or SI standard"
  },
  "working": "skin_factor = 200/200 = 1.\\nt_minutes = (200 min / 1) × 1 = 200 min.\\nt_seconds = 200 × 60 = 12,000 s."
}

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche7/tranche7-results.json