Source: https://guthlabs.ai/docs/instruments/factor-of-safety-allowable-stress-calculator/implementation/

instrument implementation / implementation-contract

# Factor of Safety / Allowable Stress Calculator implementation

A source-bound implementation contract for Factor of Safety / Allowable Stress 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**: t5-185

**Effect**: Computation or source lookup only

## Input and validation requirements

A zero target safety factor produces division by zero and must be rejected. The signed-stress probe also exposes a convention hazard: literal arithmetic gives a negative safety factor, whereas the usual engineering interpretation uses stress magnitude.

## 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": {
    "mode": "SF",
    "strength_type": "yield",
    "strength": 250,
    "strength_unit": "MPa",
    "actual_stress": 100,
    "actual_stress_unit": "MPa"
  },
  "expected_outputs": {
    "SF": 2.5
  },
  "working": "SF = σ_yield / σ_actual = 250 MPa / 100 MPa = 2.5. The MPa units cancel."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/factor-of-safety-allowable-stress-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/factor-of-safety-allowable-stress-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/factor-of-safety-allowable-stress-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-tranche5/tranche5-results.json`