A
bulkhead is an upright wall within the
hull of a
ship. Other kinds of partition elements within a ship are
decks and
deckheads.
Etymology
The word
bulki meant "cargo" in
Old Norse. Sometime in the 15th century sailors and builders in Europe realized that walls within a vessel would prevent cargo from shifting during passage. In shipbuilding, any vertical panel was called a "head". So walls installed abeam (side-to-side) in a vessel's hull were called "bulkheads." Now, the term
bulkhead applies to every vertical panel aboard a ship, except for the hull itself.
Purpose
Bulkheads in a ship serve several purposes:
- increase the structural rigidity of the vessel,
- divide functional areas into rooms and
- create watertight compartments that can contain water in the case of a hull breach or other leak.
Some bulkheads and
decks are
fire-resistance rated to achieve
compartmentalisation, a
passive fire protection measure.
Requirements of bulkheads
Fire-resistance
Openings in fire-resistance rated bulkheads and decks must be
firestopped to restore the fire-resistance ratings that would otherwise be compromised, if the openings were left unsealed. The
Authority Having Jurisdiction for such measures varies depending upon the flag of the ship. Merchant vessels are typically subject to the regulations and inspections of the Coast Guards of the flag country. Combat ships are subject to the regulations set out by the navy of the country that owns the ship.
Prevention of damage from EMI and EMP
Bulkheads and decks of warships may be fully
grounded (electrically) as a
countermeasure against damage from
EMI and
EMP due to nuclear or
electromagnetic bomb detonations near the ship, which could severely damage the vital electronic
systems on a ship.
In the case of firestops, cable jacketing is usually removed within the seal and firestop rubber modules are internally fitted with copper shields, which contact the cables' armour in order to ground the seal. There are also conductive fill materials in use for that purpose, which must be in direct contact with cable armour to ensure full grounding of the bulkheads and decks.
Other uses of the term
The term was later applied to other vehicles, such as
railroad cars,
hopper cars
trams,
automobiles,
aircraft or
spacecraft, as well as to
containers,
intermediate bulk containers and
fuel tanks. In some of these cases bulkheads are airtight to prevent air leakage or the spread of a fire. The term may also be used for the "end walls" of
bulkhead flatcars.
Mechanically, a partition or panel through which connectors pass, or a connector designed to pass through a partition.
See also
