Editing Bulkhead (partition)

{{Short description|Vertical partition inside a ship}}
[[File:Compartments and watertight subdivision of a ship's hull (Seaman's Pocket-Book, 1943) (cropped).jpg|thumb|300px|Compartmentalisation of a ship, to reduce [[ship floodability|floodability]]]]
A '''bulkhead''' is an upright wall within the [[hull (watercraft)|hull]] of a ship, within the [[fuselage]] of an [[airplane]], or a car.  Other kinds of partition elements within a ship are [[deck (ship)|decks]] and [[deckhead]]s.

== Etymology ==
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|other etymologies are given, and, IMO, more likely|date=March 2017}}  Now, the term '''bulkhead''' applies to every vertical panel aboard a ship, except for the hull itself.

== History ==
{{See also|Naval history of China}}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),<ref>{{Cite book |last1=Fields |first1=Nic |url=https://www.worldcat.org/title/ocm76365221 |title=Ancient Greek warship, 500-322 BC |last2=Bull |first2=Peter |date=2007 |publisher=Osprey |isbn=978-1-84603-074-1 |series=New vanguard |location=Oxford |pages=5 |oclc=ocm76365221}}</ref> 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.<ref>{{Cite book |last=Pitassi |first=Michael |title=Hellenistic naval warfare and warships 336-30 BC: War at Sea from Alexander to Actium |date=2022 |publisher=Pen & Sword Military |isbn=978-1-3990-9760-4 |location=Barnsley (GB) |page=Chapter 3, 1 |chapter=Chapter 3 {{!}} Rams, Towers, Artillery and Tactics}}</ref>

[[File:Song Dynasty Ancient Ship of Quanzhou Bay 20061229.jpg|thumb|The remains of the [[Quanzhou ship]], dated to the [[Song dynasty]] and discovered in 1973]]

Bulkhead partitions are considered to have been a feature of Chinese [[Junk (ship)|junks]], a type of ship. Song dynasty author [[Zhu Yu (author)|Zhu Yu]] (fl. 12th century) wrote in his book of 1119 that the [[Hull (watercraft)|hulls]] of [[Junk (ship)|Chinese ships]] had a bulkhead build. The 5th-century book ''Garden of Strange Things'' by Liu Jingshu mentioned that a ship could allow water to enter the bottom without sinking. Archaeological evidence of bulkhead partitions has been found on a 24&nbsp;m (78&nbsp;ft) long Song dynasty ship dredged from the waters off the southern coast of China in 1973, the hull of the ship divided into twelve walled [[Compartment (ship)|compartmental]] sections built [[Waterproofing|watertight]], dated to about 1277.<ref name="Needham"/><ref>Ebrey, Patricia Buckley, Anne Walthall, James B. Palais (2006). ''East Asia: A Cultural, Social, and Political History''. Boston: Houghton Mifflin Company. {{ISBN|0-618-13384-4}}, p. 159.</ref>

Texts written by writers such as [[Marco Polo]] (1254–1324), [[Ibn Battuta]] (1304–1369), [[Niccolò Da Conti]] (1395–1469), and [[Benjamin Franklin]] (1706–1790) describe the bulkhead partitions of East Asian shipbuilding.<ref name="Needham">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.</ref><ref>Gernet, Jacques. (1996). ''A History of Chinese Civilization''. Translated by J.R. Foster and Charles Hartman. Cambridge: Cambridge University Press. {{ISBN|0-521-49781-7}}, p. 327.</ref> An account of the early fifteenth century describes Indian ships as being built in compartments so that even if one part was damaged, the rest remained intact—a forerunner of the modern day watertight compartments using bulkheads.<ref name=indiannavy>[http://indiannavy.nic.in/ ''Early History'' (Indian Navy)], [[National Informatics Center]], [[Government of India]].</ref>

As wood began to be replaced by iron in European ships in the 18th century, new structures, like bulkheads, started to become prevalent.<ref>{{Cite journal |last=Kenchington |first=Trevor |date=1993-01-01 |title=The Structures of English Wooden Ships: William Sutherland's Ship, circa 1710 |url=http://dx.doi.org/10.25071/2561-5467.766 |journal=The Northern Mariner / Le Marin du Nord |volume=3 |issue=1 |pages=1–43 |doi=10.25071/2561-5467.766 |issn=2561-5467}}</ref> Bulkhead partitions became widespread in Western shipbuilding during the early 19th century.<ref name="Needham"/> [[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."<ref name="Franklin">{{cite book|author=Benjamin Franklin|title=The writings of Benjamin Franklin|url=https://archive.org/details/writingsbenjami01frangoog|access-date=5 October 2012|year=1906|publisher=The Macmillan Company|pages=[https://archive.org/details/writingsbenjami01frangoog/page/n180 148]–149}}</ref> A 19th-century book on shipbuilding attributes the introduction of watertight bulkheads to Charles Wye Williams, known for his [[City of Dublin Steam Packet Company|steamships]].<ref name="Reed">{{cite book|author=Sir Edward James Reed|title=Shipbuilding in iron and steel: A practical treatise, giving full details of construction, processes of manufacture, and building arrangements|url=https://books.google.com/books?id=Vh1EAAAAYAAJ&pg=PA213|access-date=5 October 2012|year=1869|publisher=Murray|page=213}}</ref>

== Purpose ==
Bulkheads in a ship serve several purposes: 
* increase the structural rigidity of the vessel, 
* divide functional areas into rooms and 
* create [[Compartment (ship)|watertight compartment]]s that can [[ship floodability|contain water]] in the case of a hull breach or other leak. 
* some bulkheads and [[deck (ship)|deck]]s are [[fire-resistance rating|fire-resistance rated]] to achieve [[Compartmentalization (fire protection)|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.<ref>{{Cite book |last1=Eyres |first1=David J. |title=Ship construction |last2=Bruce |first2=George J. |date=2012 |publisher=Butterworth-Heinemann |isbn=978-0-08-097239-8 |edition=7th |location=Amsterdam, [Netherlands] |pages=180}}</ref>

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 class|economy]] and [[business class|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 ==
{{unreferenced section|date=January 2018}}

=== Fire-resistance ===
[[Image:Marine firestop.jpg|thumb|right|[[Firestop]]ped [[electrical cable]] penetration in a '''bulkhead''' which is required to have a [[fire-resistance rating]]. The firestop is made of a purpose-designed [[putty]] on the outside and a proprietary [[cement]]itious fill on the inside.]]
Openings in fire-resistance rated bulkheads and decks must be [[firestop]]ped to restore the fire-resistance ratings that would otherwise be compromised if the openings were left unsealed. The [[Construction#Authority having jurisdiction|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 ===
Bulkheads and decks of warships may be fully [[Ground (electricity)|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 to ground the seal.

== Automotive ==
Most passenger vehicles and some freight vehicles will have a bulkhead which separates the engine compartment from the passenger compartment or cab;<ref>{{cite web |url=http://www.automotivedictionary.org/Bulkhead |title = Bulkhead definition {{!}} The Free Automotive Dictionary}}</ref> 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 ==
The term was later applied to other vehicles, such as [[railroad car]]s, [[hopper car]]s, [[tram]]s, [[automobile]]s, [[aircraft]] or [[spacecraft]], as well as to [[Containerization|containers]], [[intermediate bulk container]]s and [[fuel tank]]s. 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 [[Flatcar#Bulkhead flatcars|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.<ref name="Mechanical Research">{{cite web |title=Bulkheads and Large Isolation Barriers |url=https://mechanicalresearch.com/products/bulkheads/ |website=Mechanical Research & Design, Inc. |access-date=20 July 2022}}</ref>

== See also ==
{{Columns-list|colwidth=30em|
*[[Compartmentalization (fire protection)]]
*[[Fire protection]]
*[[Fireproofing]]
*[[Intumescent]]
*[[Rear pressure bulkhead]]
*[[Structural steel]]
}}

== References ==
{{Reflist}}

== External links ==
{{Commons category|Bulkheads}}
* [https://www.britannica.com/eb/topic-84303/bulkhead ''Britannica'' definition]
* [http://www.merriam-webster.com/dictionary/bulkhead ''Merriam-Webster'' definition]
* [https://web.archive.org/web/20090226083933/http://www.wipo.int/pctdb/en/wo.jsp?wo=2004033275 WIPO Bulkhead for motor vehicle]
* [https://web.archive.org/web/20080228065528/http://www.forces.gc.ca/admmat/dgmpd/jss/docs/Acronyms_Definitions_PD_SOW_12_May_06.pdf Canadian Armed Forces Glossary, see '''Fire Zone''', page 5 of 14]
* [http://exchange.dnv.com/taridocs/TA-CERT/36%5C04543736.htm Det Norske Veritas Type Approval for a fire damper inside and A60 bulkhead] {{Webarchive|url=https://web.archive.org/web/20160407184913/https://exchange.dnv.com/taridocs/TA-CERT/36%5C04543736.htm |date=2016-04-07 }}
* [http://www.freepatentsonline.com/6510807.html Subject-related patent by Free Patents Online]
* [https://web.archive.org/web/20080228065529/http://www.martrans.org:8093/symposium/papers/Track%20A/A11%20devanney.pdf An example treatise on the use of A60 bulkheads onboard tankers].

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[[Category:Shipbuilding]]
[[Category:Nautical terminology]]
[[Category:Chinese inventions]]
[[Category:Ship compartments]]