Density scale changelog
A changelog is only worth reading if it says what actually changed. This page records each revision to the density-to-class scale this site uses, band by band, with the docket it came from and the date it took effect. Where a former value was never captured, the row says so rather than being filled in. The page is generated from the same file the calculator reads, so it cannot describe a scale that is not the one in use.
NMFC-2025-1
The 11-subprovision density scale was expanded to 13 subprovisions. Two bands were added at the top of the scale; the lower ten bands are unchanged. This was an expansion, not a replacement of the scale.
NMFC Docket 2025-1. Effective , published . Last verified against the primary source on .
Change type: expansion. Subprovisions: 11 before this version, 13 after — 2 new bands, 10 unchanged, 1 not recorded.
No earlier version of this scale is recorded on this site.
What this record does not contain. The superseded 11-subprovision table's exact per-band wording was not captured before it was replaced, and NMFTA publishes only its most recent docket on the public docket page. We therefore record this change at the level the surviving evidence supports instead of reconstructing the old table from memory. Reconstructing it would mean publishing numbers we cannot point to a source for.
| Sub | Density (lb/ft³), as published | Class | Change |
|---|---|---|---|
| 1 | Less than 1 | 400 | unchanged |
| 2 | 1 but less than 2 | 300 | unchanged |
| 3 | 2 but less than 4 | 250 | unchanged |
| 4 | 4 but less than 6 | 175 | unchanged |
| 5 | 6 but less than 8 | 125 | unchanged |
| 6 | 8 but less than 10 | 100 | unchanged |
| 7 | 10 but less than 12 | 92.5 | unchanged |
| 8 | 12 but less than 15 | 85 | unchanged |
| 9 | 15 but less than 22.5 | 70 | unchanged |
| 10 | 22.5 but less than 30 | 65 | unchanged |
| 11 | 30 but less than 35 | 60 | not recorded |
| 12 | 35 but less than 50 | 55 | new band |
| 13 | 50 or greater | 50 | new band |
Rows with a caveat.
Sub 11: The class value 60 is verified for the current scale. What is not directly sourced is the previous upper end of this band: the current wording stops at 35, and the two added bands start there. Whether the superseded table's top band read "30 or greater" is consistent with an 11-row table but we did not capture it, so we do not assert it.
Reading this record
Each entry covers one version of the scale. The rows beneath it list every subprovision in that version, in official order, with the class value and the published density wording that version carries.
The change column is deliberately narrow. "Unchanged" means the band survived the revision with the same class value and the same wording. "New band" means the band did not exist in the version before it. "Not recorded" means we know the current value but not the previous one.
Why one row says not recorded
NMFTA publishes only the most recent docket on its public docket page. The 11-subprovision wording that preceded the current scale was replaced, and we did not capture it while it was still published.
That row could have been filled in from memory, from a third-party copy, or by assuming the top band simply read "30 or greater". We did none of those. A reconstructed old value that happens to be right is indistinguishable from one that happens to be wrong, and the point of this page is that you can check it.
How this page stays in step with the data
Every value here comes from the same data file the calculator reads. A build in which the scale changed but no matching entry exists here does not start, so a stale changelog is not a state this site can be in.
Sources are listed with the entry they belong to, and an archived copy is linked beside the live one, because the live one can disappear.
Frequently asked
Why is there only one entry?
Because the density scale has changed once since we began recording it. The 13-subprovision structure came from Docket 2025-1 and took effect on July 19, 2025. When NMFTA publishes the next revision it appears here as a new entry rather than as an edit to this one.
Do you keep the old numbers?
Where we have them, yes. Each entry is additive and earlier entries are not edited, so the record shows what the scale said at the time. Where we do not have them, the row says not recorded and explains what is missing.
Can I cite this page?
Cite the primary source instead; it is linked on every entry. This page is here to show what changed and when, not to be the authority on the values themselves.
Data source verified:
Primary source: NMFTA Disposition Bulletin 1371 — density and class breaks for the 13-subprovision structure
Archived copy: snapshot 0, snapshot 1