{
  "version": "1.0.0",
  "accessed": "2026-10-29",
  "sources": [
    {
      "id": "nist",
      "title": "NIST Guide to the SI, Chapter 5, Table 6",
      "url": "https://www.nist.gov/pml/special-publication-811/nist-guide-si-chapter-5-units-outside-si",
      "supports": "1 min = 60 s; 1 h = 3600 s; unit ratios only"
    },
    {
      "id": "bipm",
      "title": "BIPM SI Brochure, 9th edition, updated 2026, Table 8",
      "url": "https://doi.org/10.59161/AUEZ1291",
      "supports": "Unit conversion coefficients only"
    },
    {
      "id": "bipm-update",
      "title": "Updated SI Brochure clarifies the status of non-SI units",
      "url": "https://www.bipm.org/en/-/2026-06-04-updated-si-brochure-clarifies-the-status-of-non-si-units",
      "supports": "June 2026 revision: non-SI units have no special status in SI. Older NIST status labels are not adopted as current normative claims."
    }
  ],
  "attribution_boundary": "Chart and precision findings are own calculations from the ratios, not findings attributed to or endorsed by NIST/BIPM. No source images or large text extracts reproduced."
}