水密隔舱（或称水密舱，Watertight Bulkhead）是一种造船技术，指的是将船体分成许多个舱区，各个互不相通，这样当船在航行时，如果某几个舱区破损进水，船仍然不会沉没。这样的设计提升了船的安全性。

水密舱壁是一种在规定水压下不渗透水的舱壁，将船体内部空间划分成若干个水密舱室。水密舱壁的出现，才产生了水密隔舱，使船舶在破损时具有足够浮力和稳性。 　　

水密舱壁作用：

一、是能起到加固船体作用，增加船体构造强度。由于舱壁跟船壳板紧密连结，起着加固船体的作用，不但增加了船舶整体的横向强度，而且取代了加设肋骨的工艺，使造船工艺简化。

A firestop is a fire protection system made of various components used to seal openings and joints in fire-resistance rated wall and/or floor assemblies. For penetrating cables, these can also be called as Multi Cable Transits (MCTs).

Firestops are designed to restore the fire-resistance ratings of wall and/or floor assemblies by impeding the spread of fire by filling the openings with fire-resistant materials. Unprotected openings in fire separations cancel out the fire-resistance ratings of the fire separations, allowing the spread of fire, usually past the limits of the fire safety plan of a building.