Air Density Calculator 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

t5-164

Effect

Computation or source lookup only

Input and validation requirements

An input at exactly -273.15 C produces a zero-kelvin denominator and must be rejected rather than evaluated. The specification also omits the saturation-vapor-pressure formula and any ice/water branch convention, leaving a branch-selection hazard near 0 C.

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": {
    "temperature_c": 15,
    "pressure_pa": 101325,
    "relative_humidity": 0.5
  },
  "expected_outputs": {
    "air_density_kg_m3": 1.2211
  },
  "working": "T = 15 + 273.15 = 288.15 K. Using Tetens, es ≈ 1705 Pa. Pv = 0.5 × 1705 = 852.5 Pa. Pd = 101325 − 852.5 = 100472.5 Pa. Rd×T = 287.05×288.15 = 82713.4575. Rv×T = 461.495×288.15 = 132979.78425. Dry contribution = 100472.5/82713.4575 ≈ 1.214706. Vapor contribution = 852.5/132979.78425 ≈ 0.006411. Density = 1.214706 + 0.006411 = 1.221117 ≈ 1.2211 kg/m³."
}

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-tranche5/tranche5-results.json