Source: https://guthlabs.ai/docs/instruments/thermal-expansion-calculator/implementation/

instrument implementation / implementation-contract

# Thermal Expansion Calculator implementation

A source-bound implementation contract for Thermal Expansion Calculator; 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**: t7-011

**Effect**: Computation or source lookup only

## Input and validation requirements

The calculator needs explicit range handling because an extreme but syntactically valid input overflows to infinity. It also has a unit-convention hazard when ΔT is supplied in °F while α is per °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": {
    "material": "copper",
    "alpha_per_K": 0.0000165,
    "L0_m": 2,
    "T0_C": 20,
    "T1_C": 120,
    "delta_T_C": 100
  },
  "expected_outputs": {
    "delta_L_m": 0.0033,
    "new_length_m": 2.0033
  },
  "reference_data": {
    "material": "copper",
    "alpha_per_K": 0.0000165,
    "table_fragment": "Copper linear CTE near room temperature = 16.5 × 10^-6 K^-1",
    "source_convention": "widely tabulated standard value"
  },
  "working": "ΔT=T1−T0=120−20=100 °C. ΔL=αL0ΔT=(16.5×10^-6 K^-1)(2.0 m)(100 K)=0.0033 m. New length=L0+ΔL=2.0+0.0033=2.0033 m."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/thermal-expansion-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/thermal-expansion-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/thermal-expansion-calculator/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-tranche7/tranche7-results.json`