46 CFR § 174.090 - Permeability of spaces.

---
identifier: "/us/cfr/t46/s174.090"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "46 CFR § 174.090 - Permeability of spaces."
title_number: 46
title_name: "Shipping"
section_number: "174.090"
section_name: "Permeability of spaces."
chapter_name: "COAST GUARD, DEPARTMENT OF HOMELAND SECURITY"
subchapter_number: "S"
subchapter_name: "SUBDIVISION AND STABILITY"
part_number: "174"
part_name: "SPECIAL RULES PERTAINING TO SPECIFIC VESSEL TYPES"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
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."
regulatory_source: "CGD 79-023, 48 FR 51048, Nov. 4, 1983, unless otherwise noted."
cfr_part: "174"
---


# 174.090 Permeability of spaces.

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. |
| Other liquid tanks | 95 or 0. |
| Whichever results in the more disabling condition. |  |
| If tanks are partially filled, the permeability must be determined from the actual density and amount of liquid carried. |  |