---
kind: "section"
citation: "46 C.F.R. § 174.090"
title: "46"
number: "174.090"
heading: "Permeability of spaces."
url: "https://uscodex.org/cfr/46/174.090"
---

# §174.090. Permeability of spaces.


When doing the calculations required in [§ 174.065](/cfr/46/174.065.md)—

- (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.

## Notes

### Authority

Authority: 42 U.S.C. 9118, 9119, 9153; 43 U.S.C. 1333; 46 U.S.C. 3306, 3703; E.O. 12234, 45 FR 58801, 3 CFR, 1980 Comp., p. 277; Department of Homeland Security Delegation No. 0170.1. Section 174.180 also issued under sec. 617, Pub. L. 111-281, 124 Stat. 2905.

### Source

Source: CGD 79-023, 48 FR 51048, Nov. 4, 1983, unless otherwise noted.