Source: https://guthlabs.ai/docs/instruments/wet-bulb-temperature-estimator/implementation/

instrument implementation / implementation-contract

# Wet-Bulb Temperature Estimator implementation

A source-bound implementation contract for Wet-Bulb Temperature Estimator; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## 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**: t6-015

**Effect**: Computation or source lookup only

## Input and validation requirements

A negative-RH input drives the RH^(3/2) term outside the real-number domain and can yield NaN unless rejected. The specification also leaves the Stull-versus-iterative method and the validity-limit branch unspecified, while RH unit convention can be interpreted as either percent or fraction.

## 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": {
    "method": "Stull 2011",
    "dry_bulb_C": 20,
    "RH_percent": 50,
    "pressure_kPa": 101.325
  },
  "expected_outputs": {
    "wet_bulb_C": 13.699
  },
  "working": "Use Tw = T*atan(0.151977*sqrt(RH+8.313659)) + atan(T+RH) - atan(RH-1.676331) + 0.00391838*RH^(3/2)*atan(0.023101*RH) - 4.686035. sqrt(50+8.313659)=sqrt(58.313659)=7.63634. First angle: atan(0.151977*7.63634)=atan(1.16055)=0.859571, so T term=20*0.859571=17.1914. atan(20+50)=atan(70)=1.556512. atan(50-1.676331)=atan(48.323669)=1.550105. RH term: 50^(3/2)=353.553; 0.00391838*353.553=1.38536; atan(0.023101*50)=atan(1.15505)=0.857222; product=1.18756. Therefore Tw=17.1914+1.556512-1.550105+1.18756-4.686035=13.6993 C, or 13.699 C. P is unused."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/wet-bulb-temperature-estimator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/wet-bulb-temperature-estimator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/wet-bulb-temperature-estimator/qualification/>)

## Sources and evidence

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

- `VERIFIED_LEDGER.json`

- `evidence-tranche6/tranche6-results.json`