# Banding scales

Published threshold sets for [`BandingScale`](../jouleclaw-rs/crates/jouleclaw-compliance/src/banding.rs).

## Why scales live here and not in the crate

`BandingScale::rate` turns a measurement into an A–G band. The crate ships the
**shape** of a scale and no scale at all, deliberately: which thresholds are
correct for a given metric is a policy question a library has no standing to
settle. Baking one in would repeat the mistake the type was written to retire —
`EedReport::is_compliant`'s `pue < 1.5 && renewable_pct >= 50.0`, two magic
floats with no provenance, no version, and no way to say which instrument they
encoded — only with more ceremony.

So a scale is **data**, published here with its sources beside it. `BandingScale`
derives `Deserialize`, so a pack loads with `serde_json::from_str` and needs no
crate code:

```rust
let scale: BandingScale = serde_json::from_str(include_str!("…/eu.eed.dr2026.pue.json"))?;
let rating = scale.rate(report.pue_milli())?;
```

## What a pack must carry

Each `<scale_id>.json` is exactly a `BandingScale`. Each is accompanied by
`<scale_id>.provenance.json` recording where the numbers came from, the status
of that source, what the pack deliberately omits, and the reuse terms.

A pack with no provenance file is not publishable here. A threshold whose origin
is unstated is the thing this directory exists to replace.

## The scale id is a version, and never edited in place

Ratings cite their `scale_id`, and `Rating::comparable_with` refuses to rank two
ratings from different scales. That only works if an id means one fixed set of
boundaries forever. When a source instrument changes, the result is a **new
id** — never an edit to an existing file, which would silently re-band every
grade already issued under it.

## Current packs

| scale | metric | source status |
|---|---|---|
| `eu.eed.dr2026.pue/1` | PUE, milli-units | **Draft** delegated regulation (revised 2026-07-02, not adopted) |

A grade produced from a draft instrument is not a regulatory determination, and
the provenance file says so in those words. These packs exist so that a figure
can be banded *against a stated source*; they do not make the source binding,
and they do not make a self-declared input measured.