Standard Applied by the app hvac.duct.gauge-schedule
Duct gauge by size and pressure class
The simplified gauge schedule the Duct tool picks metal with — by the duct's larger side or diameter and the system's pressure class — before you override it.
| When | The app uses |
|---|---|
| 1 in w.g., larger side up to 12 in | 26 ga |
| 1 in w.g., up to 30 in | 24 ga |
| 1 in w.g., up to 54 in | 22 ga |
| 1 in w.g., up to 84 in | 20 ga |
| 1 in w.g., larger | 18 ga |
| 2 in w.g., larger side up to 10 in | 26 ga |
| 3 in w.g., larger side up to 8 in | 26 ga |
- Source
- SMACNA · HVAC Duct Construction Standards, gauge tables (simplified) · read the public text
- Editions checked
- 2020
- Used by
- Duct Schedule
- Amendments
No state or local amendment to this rule is on file. Not on file means the model code as written — check your jurisdiction.
An industry standard the trade builds to.
SMACNA's construction standard sets gauge together with reinforcement: a thinner sheet with more frequent reinforcement can meet the same pressure class as a thicker one with less. An estimate does not need that trade-off resolved; it needs a defensible gauge per size to turn feet into pounds.
What the app does with it
The Duct tool picks a gauge from this schedule the moment you give a run a size, keyed on the larger rectangular side or the round diameter and on the pressure class (½, 1, 2 or 3 in w.g.). The schedule steps thinner sizes down one gauge at higher pressure classes. Every pick is an override away: change it in the size chip and the weight recalculates.
What it does not do
This is the simplified schedule, gauge only. It does not choose reinforcement, joint type, or seam, and it is not the SMACNA table reprinted — the standard's own tables are the source for anything submitted.
Cited by section, not reprinted: the code text belongs to its publisher. Company practice is not a rule here — it lives with your pricing.