# Title 46

## SECTION 172.240

### 172.240 Permeability of spaces.

§ 172.240 Permeability of spaces.When doing the calculations required in § 172.225,

(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.

Table 172.240 - Permeability

Spaces and tanks | Permeability (percent) |
---|---|

Storeroom spaces | 60 |

Accommodations spaces | 95 |

Voids | 95 |

Consumable liquid tanks | ^{1} 95 or 0 |

Other liquid tanks | ^{2} 95 or 0 |

Cargo (completely filled) | 60 |

Cargo (empty) | 95 |

Machinery | 85 |

^{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.