Bulkhead (partition)
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A bulkhead is an upright wall within the hull of a ship, within the fuselage of an airplane, or a car. Other kinds of partition elements within a ship are decks and deckheads.
Etymology
[edit]The word bulki meant "cargo" in Old Norse. During 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".[dubious – discuss] Now, the term bulkhead applies to every vertical panel aboard a ship, except for the hull itself.
History
[edit]Bulkheads were known to the ancient Greeks, who employed bulkheads in triremes to support the back of rams. By the Athenian trireme era (500 BC),[1] the hull was strengthened by enclosing the bow behind the ram, forming a bulkhead compartment. Instead of using bulkheads to protect ships against rams, Greeks preferred to reinforce the hull with extra timber along the waterline, making larger ships almost resistant to ramming by smaller ones.[2] Similar to how ships of the Age of Sail allocated more timber to strengthen the hull, so that enemy ships had to be close for cannon fire to be damaging.
As wood began to be replaced by iron in European ships in the 18th century, new structures, like bulkheads, started to become prevalent.[3] Bulkhead partitions became widespread in Western shipbuilding during the early 19th century.[4] Benjamin Franklin wrote in a 1787 letter that "as these vessels are not to be laden with goods, their holds may without inconvenience be divided into separate apartments, after the Chinese manner, and each of these apartments caulked tight so as to keep out water."[5] A 19th century book on shipbuilding attributes the introduction of watertight bulkheads to Charles Wye Williams, known for his steamships.[6]
Purpose
[edit]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; see firewall (construction).
Not all bulkheads are intended to be watertight, in modern ships the bottom floor is supported against the hull by transverse walls(bulkheads) and longitudinal walls, being common to use bulkheads with lightening holes.[7]
On an aircraft, bulkheads divide the cabin into multiple areas. On passenger aircraft a common application is for physically dividing cabins used for different classes of service (e.g. economy and business.) On combination cargo/ passenger, or "combi" aircraft, bulkhead walls are inserted to divide areas intended for passenger seating and cargo storage.
Requirements of bulkheads
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Fire-resistance
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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 electromagnetic damage
[edit]Bulkheads and decks of warships may be fully electrically grounded as a countermeasure against damage from electromagnetic interference and electromagnetic pulse due to nearby nuclear or electromagnetic bomb detonations, 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.
Automotive
[edit]Most passenger vehicles and some freight vehicles will have a bulkhead which separates the engine compartment from the passenger compartment or cab;[8] the automotive use is analogous to the nautical term in that the bulkhead is an internal wall which separates different parts of the vehicle. Some passenger vehicles (particularly sedan/saloon-type vehicles) will also have a rear bulkhead, which separates the passenger compartment from the trunk/boot.
Other uses of the term
[edit]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.
In architecture the term is frequently used to denote any boxed in beam or other downstand from a ceiling and by extension even the vertical downstand face of an area of lower ceiling beyond. This usage presumably derives from experience on boats where to maintain the structural function personnel openings through bulkheads always retain a portion of the bulkhead crossing the head of the opening. Head strikes on these downstand elements are commonplace, hence in architecture any overhead downstand element comes to be referred to as a bulkhead.
Bulkhead also refers to a moveable structure often found in an ((Olympic-size swimming pool)), as a means to set the pool into a “double-ended short course” configuration, or long-course, depending on the type of event being run. Pool bulkheads are usually air-fillable, but power driven solutions do exist.
The term is also used to refer to large retroactively installed pressure barriers for temporary or permanent use, often during maintenance or construction activities.[9]
See also
[edit]References
[edit]- ^ Fields, Nic; Bull, Peter (2007). Ancient Greek warship, 500-322 BC. New vanguard. Oxford: Osprey. p. 5. ISBN 978-1-84603-074-1. OCLC 76365221.
- ^ Pitassi, Michael (2022). "Chapter 3 | Rams, Towers, Artillery and Tactics". Hellenistic naval warfare and warships 336-30 BC: War at Sea from Alexander to Actium. Barnsley (GB): Pen & Sword Military. p. Chapter 3, 1. ISBN 978-1-3990-9760-4.
- ^ Kenchington, Trevor (1993-01-01). "The Structures of English Wooden Ships: William Sutherland's Ship, circa 1710". The Northern Mariner / Le marin du nord. 3 (1): 1–43. doi:10.25071/2561-5467.766. ISSN 2561-5467.
- ^ Needham, Joseph. (1971). Science and Civilization in China: Volume 4, Physics and Physical Technology, Part 3, Civil Engineering and Nautics. Cambridge University Press., reprinted Taipei: Caves Books, Ltd.(1986), pp. 391, 420–422, 462-463.
- ^ Benjamin Franklin (1906). The writings of Benjamin Franklin. The Macmillan Company. pp. 148–149. Retrieved 5 October 2012.
- ^ Sir Edward James Reed (1869). Shipbuilding in iron and steel: A practical treatise, giving full details of construction, processes of manufacture, and building arrangements. Murray. p. 213. Retrieved 5 October 2012.
- ^ Eyres, David J.; Bruce, George J. (2012). Ship construction (7th ed.). Amsterdam, [Netherlands]: Butterworth-Heinemann. p. 180. ISBN 978-0-08-097239-8.
- ^ "Bulkhead definition | The Free Automotive Dictionary".
- ^ "Bulkheads and Large Isolation Barriers". Mechanical Research & Design, Inc. Retrieved 20 July 2022.
External links
[edit]
- Britannica definition
- Merriam-Webster definition
- WIPO Bulkhead for motor vehicle
- Canadian Armed Forces Glossary, see Fire Zone, page 5 of 14
- Det Norske Veritas Type Approval for a fire damper inside and A60 bulkhead Archived 2016-04-07 at the Wayback Machine
- Subject-related patent by Free Patents Online
- An example treatise on the use of A60 bulkheads onboard tankers.
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