U.S. Code of Federal Regulations
Regulations most recently checked for updates: Aug 27, 2025
When doing the calculations required in § 174.065—
(a) The permeability of a floodable space, other than a machinery space, must be as listed in Table 174.090; and
(b) Calculations in which a machinery space is treated as a floodable space must be based on an assumed machinery space permeability of 85%, unless the use of an assumed permeability of less than 85% is justified in detail.
Table 174.090—Permeability
| Spaces and tanks | Permeability (percent) |
|---|---|
| Storeroom spaces | 60. |
| Accommodation spaces | 95. |
| Voids | 95. |
| Consumable liquid tanks | 95 or 0. 1 |
| Other liquid tanks | 95 or 0. 2 |
1 Whichever results in the more disabling condition.
2 If tanks are partially filled, the permeability must be determined from the actual density and amount of liquid carried.
