Relative Humidity ↔ Dew Point Converter

Inspectable records

Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Area

Thermodynamics, Fluids & Aero

Tranche

tranche-4

Evidence ID

t4-048

Ledger rows

1

No ledger note is attached.

Review findings

The forward formula is correct under the stated assumptions, but the coefficient values, inverse formula, valid input domains, and temperature-unit contract must be specified before release. Verdict is NEEDS_REVIEW because these ambiguities affect correctness and implementation.

Formula and scope findings

• The Magnus dew-point formula is standard only after specifying the coefficient set; a and b are not given. The test vectors below assume a=17.62 and b=243.12.
• The specification claims bidirectional conversion, but it provides only the forward dew-point formula. The inverse formula for relative humidity is missing: RH=100·exp(γ−aT/(b+T)), where γ=a·Td/(b+Td).
• The claimed ±0.4°C typical accuracy is coefficient-, temperature-, and humidity-range-dependent and must not be presented as universal.

Unit assumptions

• T, Td, and the Magnus coefficients use degrees Celsius; Fahrenheit or Kelvin inputs require explicit conversion before applying the formula.
• RH is a percentage in the range 0<RH≤100; RH=100 means saturation.
• For the vectors, a=17.62 and b=243.12°C are assumed.
• ln is the natural logarithm and exp is the natural exponential function.

Boundary hardening

BREAK_CLAIMED · SELF_FLAGGED

The formula has an undefined RH=0 input that requires validation, and an unlabeled RH value such as 0.5 can produce either 9.25519°C or −44.60415°C depending on percent-versus-fraction convention.

Errata and corrections

No applied erratum is attached to this unique-name record.

Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

{
  "inputs": {
    "dry_bulb_temperature_C": 20,
    "relative_humidity_percent": 50
  },
  "expected_outputs": {
    "dew_point_temperature_C": 9.2552
  },
  "working": "γ=ln(50/100)+(17.62×20)/(243.12+20) = ln(0.5)+352.4/263.12 = -0.693147+1.339313 = 0.646166. Td=243.12×0.646166/(17.62-0.646166) = 157.0958/16.973834 = 9.2552°C."
}

Related workflows

Sources and evidence

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

• VERIFIED_LEDGER.json · VERIFIED_CLEAN
• evidence-tranche4/tranche4-results.json
• BOUNDARY_HAZARD_CATALOG.json