---
kind: "section"
citation: "46 C.F.R. § 172.240"
title: "46"
number: "172.240"
heading: "Permeability of spaces."
url: "https://uscodex.org/cfr/46/172.240"
---

# §172.240. Permeability of spaces.


When doing the calculations required in [§ 172.225](/cfr/46/172.225.md),

- (a) The permeability of a floodable space, other than a machinery or cargo space, must be assumed as listed in Table 172.240;
- (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; and
- (c) Calculations in which a cargo space that is completely filled is considered flooded must be based on an assumed cargo space permeability of 60% unless the use of an assumed permeability of less than 60% is justified in detail. If the cargo space is not completely filled, a cargo space permeability of 95% must be assumed unless the use of an assumed permeability of less than 95% is justified in detail.

## Notes

### Source

Source: CGD 80-159, 51 FR 33059, Sept. 18, 1986, unless otherwise noted.

### Authority

Authority: 46 U.S.C. 3306, 3703, 5115; E.O. 12234, 45 FR 58801, 3 CFR, 1980 Comp., p. 277; DHS Delegation 00170.1, Revision No. 01.2.

### Source

Source: CGD 79-023, 48 FR 51040, Nov. 4, 1983, unless otherwise noted.