ASHRAE A1–A4 recommended inlet band; allowable A1 15–32, A2 10–35, A3 5–40, A4 5–45 °C; H1 narrower at 18–22 recommended / 5–25 allowable
18–27 °Cobserved
| Value kind | observed — Reported measurements, counts, and specifications keep the precision and scope stated by their source; an exact specification is not treated as a range. |
|---|---|
| Scope | Classes A1–A4. The high-density H1 class has a narrower 18–22 °C recommended and 5–25 °C allowable range, and the equipment OEM determines which class applies. Allowable exposure is qualified operation, not the reliability of recommended conditions, and the associated humidity and altitude limits apply alongside the dry-bulb band. |
| As of | 2024 |
| Source | ASHRAE TC 9.9 Thermal Guidelines (5th ed.) |
| Review | checking…review by 2027-05-09 · slow cadence |
| Recorded changes | last 2026-06-29 |
| Claim id | ashrae-recommended-inlet-band-allowable-a1-15 |
Where the guide uses it
← Full numbers register — every date-stamped figure in the guide, with revision history.