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`BandingScale` deliberately ships no canonical scale: which thresholds are correct for a metric is a policy question a library has no standing to settle, and baking one in would repeat the mistake the type was written to retire — `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. So the EU draft's PUE bands are published as **data**, in `jouleclaw/scales/v1/`, with their sources beside them. `BandingScale` already derives `Deserialize`, so a pack loads with `serde_json::from_str` and this adds no crate code at all — which is the point. Each pack is exactly a `BandingScale`, accompanied by a provenance file recording where the numbers came from, the status of that source, what the pack omits, and the reuse terms. A pack with no provenance file is not publishable here; a threshold whose origin is unstated is the thing the directory exists to replace. Three things the provenance says plainly: - **The instrument is a DRAFT** — registered 2026-03-26, revised 2026-07-02, not adopted and not in the Official Journal, with first labels expected 2027-08-15. A grade produced from it is not a regulatory determination. - **WUE is deliberately absent.** The instrument sets the grade from PUE *and* WUE, and only the PUE bands were read from it. Inventing WUE boundaries to complete the set would be exactly the failure this design prevents: a threshold with no provenance, presented as though it had one. A test asserts that a composite built from this pack reports `covers(&["pue","wue"]) == false`, so a half-graded facility cannot read as graded. - **The instrument permits calculation and estimates**, not only measurement, so a PUE fed to this scale may be self-declared. The scale bands whatever number it is given and says nothing about how that number was acquired. The scale id is a version and is never edited in place. Ratings cite their `scale_id` and `comparable_with` refuses to rank across scales, which only works if an id means one fixed set of boundaries forever — so a changed instrument is a new id, never an edit that would silently re-band grades already issued. The pack is tested, not merely committed: it is `include_str!`-ed, deserialized, validated and banded, and the test pins that its last boundary is **1900** — this file's own example fixture uses 2000, and only one of the two is sourced. Verified: 52 jouleclaw-compliance tests pass (2 new). Co-Authored-By: Claude Opus 5 <[email protected]>
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Banding scales
Published threshold sets for BandingScale.
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:
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.