# Severity & probability scales — MIL-STD-882E (US public domain)

Open S/O anchor for the IACE auto-FMEA. The 1–10 projection used in code is
BreakPilot's own; these public-domain categories provide the defensible anchor
(no copyrighted AIAG-VDA/SAE 1–10 table is used). Ingested into `bp_iace_fmea_kb`.

## Source
- **Source:** US DoD — MIL-STD-882E, *System Safety* (Distribution Statement A, approved for public release)
- **License:** US Government work — **public domain**
- **Attribution:** `Source: MIL-STD-882E (US DoD), public domain`
- **Retrieved:** 2026-06 · **Ref:** DLA QuickSearch (ident 36027)

## Table I — Severity (→ our 1–10 S)
| Cat | Severity | Threshold | our S |
|---|---|---|---|
| I | Catastrophic | Death, permanent total disability, irreversible severe environmental damage | 10 |
| II | Critical | Permanent partial disability; hospitalisation of multiple persons | 7 |
| III | Marginal | Injury/illness with lost work day(s) | 4 |
| IV | Negligible | Minor injury, no lost work day | 2 |

## Table II — Probability (individual item) (→ our 1–10 O)
| Lvl | Name | Qualitative | rate band (/h, our calibration) | our O |
|---|---|---|---|---|
| A | Frequent | likely to occur often | ≥ 1e-1 | 10 |
| B | Probable | will occur several times | 1e-2 … 1e-1 | 8 |
| C | Occasional | likely to occur sometime | 1e-3 … 1e-2 | 6 |
| D | Remote | unlikely but possible | 1e-6 … 1e-3 | 4 |
| E | Improbable | so unlikely ~ may not occur | < 1e-6 | 2 |
| F | Eliminated | incapable of occurrence | 0 | 1 |

## Detection (no government scale)
Detection is an AIAG/SAE concept with no public-domain table. IACE defines its
OWN 1–10 detection scale grounded on the generic **diagnostic-coverage** concept
(1 = built-in diagnostic always catches it … 10 = latent, no detection). The
IEC-61508/13849 DC tables are copyrighted and are NOT reproduced — only the
concept (in our own words) is used.

## How used in IACE
`MILStd882Severity` / `MILStd882Probability` / `OccurrenceFromRate` /
`SeverityForCategory` in fmea_data_sources.go implement these bands. Severity is
preferably resolved through the linked ISO 12100 hazard; occurrence from λp·α.
