StandardRecommended
Ventilation (detailed)
NKBA Bath 24Description
Mechanical exhaust ≥50 cfm intermittent or 20 cfm continuous, vented directly to the outside. Recommended: humidity-sensing or timer-controlled fan with run-on to clear moisture.
Why this exists
Below the floor, mildew. Run-on or humidity-sensing controls solve the 'forgot to turn on the fan' problem.
Measurements
| Property | Operator | Value | Unit | Note |
|---|---|---|---|---|
cfmIntermittent | min | 50 | cfm | |
cfmContinuous | min | 20 | cfm |
Categories
Bathroom
Applies to
- Room types: bathroom, half_bath
Source
NKBAno manifest entry
Bathroom Planning Guidelines (2024)
Section: Guideline 24
Published 2024-01-01 · last verified 2026-05-09
Solver enforcement
Browsable only — the solver does not currently enforce this directive (no spec-level data to check against). This entry exists so the architect personas can cite it in conversation and the user can read what the rule says.
Related directives
- Bathroom entry doorway · NKBA Bath 1
- Doorway swing clearance · NKBA Bath 2
- Clear floor space at fixtures · NKBA Bath 3
- Fixture clear-space overlap · NKBA Bath 4
- Toilet centerline + front (detailed) · NKBA Bath 5
Last reviewed 2026-05-09.