Bulletproof vest
Overview
 
A ballistic vest, bulletproof vest or bullet-resistant vest is an item of personal armor
Personal armor
Personal armor is the whole of protecting clothing, designed to absorb and/or deflect slashing, bludgeoning, and penetrating attacks. They were historically used to protect soldiers, whereas today, they are also used to protect police forces, private citizens and private security guards or...

 that helps absorb the impact from firearm
Firearm
A firearm is a weapon that launches one, or many, projectile at high velocity through confined burning of a propellant. This subsonic burning process is technically known as deflagration, as opposed to supersonic combustion known as a detonation. In older firearms, the propellant was typically...

-fired projectile
Projectile
A projectile is any object projected into space by the exertion of a force. Although a thrown baseball is technically a projectile too, the term more commonly refers to a weapon....

s and shrapnel
Fragmentation (weaponry)
Fragmentation is the process by which the casing of an artillery shell, bomb, grenade, etc. is shattered by the detonating high explosive filling. The correct technical terminology for these casing pieces is fragments , although shards or splinters can be used for non-preformed fragments...

 from explosions, and is worn on the torso. Soft vests are made from many layers of woven or laminated fibers and can be capable of protecting the wearer from small-caliber handgun
Handgun
A handgun is a firearm designed to be held and operated by one hand. This characteristic differentiates handguns as a general class of firearms from long guns such as rifles and shotguns ....

 and shotgun
Shotgun
A shotgun is a firearm that is usually designed to be fired from the shoulder, which uses the energy of a fixed shell to fire a number of small spherical pellets called shot, or a solid projectile called a slug...

 projectiles, and small fragments from explosives such as hand grenade
Hand grenade
A hand grenade is any small bomb that can be thrown by hand. Hand grenades are classified into three categories, explosive grenades, chemical and gas grenades. Explosive grenades are the most commonly used in modern warfare, and are designed to detonate after impact or after a set amount of time...

s.

Metal or ceramic plates can be used with a soft vest, providing additional protection from rifle
Rifle
A rifle is a firearm designed to be fired from the shoulder, with a barrel that has a helical groove or pattern of grooves cut into the barrel walls. The raised areas of the rifling are called "lands," which make contact with the projectile , imparting spin around an axis corresponding to the...

 rounds, and metallic components or tightly woven fiber layers can give soft armor resistance to stab and slash attacks from knives
Knife
A knife is a cutting tool with an exposed cutting edge or blade, hand-held or otherwise, with or without a handle. Knives were used at least two-and-a-half million years ago, as evidenced by the Oldowan tools...

 and similar close-quarter weapons.
Encyclopedia
A ballistic vest, bulletproof vest or bullet-resistant vest is an item of personal armor
Personal armor
Personal armor is the whole of protecting clothing, designed to absorb and/or deflect slashing, bludgeoning, and penetrating attacks. They were historically used to protect soldiers, whereas today, they are also used to protect police forces, private citizens and private security guards or...

 that helps absorb the impact from firearm
Firearm
A firearm is a weapon that launches one, or many, projectile at high velocity through confined burning of a propellant. This subsonic burning process is technically known as deflagration, as opposed to supersonic combustion known as a detonation. In older firearms, the propellant was typically...

-fired projectile
Projectile
A projectile is any object projected into space by the exertion of a force. Although a thrown baseball is technically a projectile too, the term more commonly refers to a weapon....

s and shrapnel
Fragmentation (weaponry)
Fragmentation is the process by which the casing of an artillery shell, bomb, grenade, etc. is shattered by the detonating high explosive filling. The correct technical terminology for these casing pieces is fragments , although shards or splinters can be used for non-preformed fragments...

 from explosions, and is worn on the torso. Soft vests are made from many layers of woven or laminated fibers and can be capable of protecting the wearer from small-caliber handgun
Handgun
A handgun is a firearm designed to be held and operated by one hand. This characteristic differentiates handguns as a general class of firearms from long guns such as rifles and shotguns ....

 and shotgun
Shotgun
A shotgun is a firearm that is usually designed to be fired from the shoulder, which uses the energy of a fixed shell to fire a number of small spherical pellets called shot, or a solid projectile called a slug...

 projectiles, and small fragments from explosives such as hand grenade
Hand grenade
A hand grenade is any small bomb that can be thrown by hand. Hand grenades are classified into three categories, explosive grenades, chemical and gas grenades. Explosive grenades are the most commonly used in modern warfare, and are designed to detonate after impact or after a set amount of time...

s.

Metal or ceramic plates can be used with a soft vest, providing additional protection from rifle
Rifle
A rifle is a firearm designed to be fired from the shoulder, with a barrel that has a helical groove or pattern of grooves cut into the barrel walls. The raised areas of the rifling are called "lands," which make contact with the projectile , imparting spin around an axis corresponding to the...

 rounds, and metallic components or tightly woven fiber layers can give soft armor resistance to stab and slash attacks from knives
Knife
A knife is a cutting tool with an exposed cutting edge or blade, hand-held or otherwise, with or without a handle. Knives were used at least two-and-a-half million years ago, as evidenced by the Oldowan tools...

 and similar close-quarter weapons. Soft vests are commonly worn by police
Police
The police is a personification of the state designated to put in practice the enforced law, protect property and reduce civil disorder in civilian matters. Their powers include the legitimized use of force...

 forces, private citizens, security guard
Security guard
A security guard is a person who is paid to protect property, assets, or people. Security guards are usually privately and formally employed personnel...

s, and bodyguard
Bodyguard
A bodyguard is a type of security operative or government agent who protects a person—usually a famous, wealthy, or politically important figure—from assault, kidnapping, assassination, stalking, loss of confidential information, terrorist attack or other threats.Most important public figures such...

s, whereas hard-plate reinforced vests are mainly worn by combat soldiers, police tactical units
SWAT
A SWAT team is an elite tactical unit in various national law enforcement departments. They are trained to perform high-risk operations that fall outside of the abilities of regular officers...

, and hostage rescue team
Hostage Rescue Team
The FBI Hostage Rescue Team is the United States Federal Bureau of Investigation's counter-terrorism paramilitary tactical team. The HRT is trained to rescue U.S. citizens and allies who are held by a hostile force, either terrorist or criminal...

s.

Modern body armor may combine a ballistic vest with other items of protective clothing, such as a combat helmet
Combat helmet
A combat helmet or battle helmet is a type of personal armor designed specifically to protect the head during combat. Helmets are among the oldest forms of personal protective equipment and are known to have been worn by the Akkadians/Sumerians in the 23rd century BC, Mycenaean Greeks since 17th...

. Vests intended for police and military use may also include ballistic shoulder and side protection armor components, and bomb disposal
Bomb disposal
Bomb disposal is the process by which hazardous explosive devices are rendered safe. Bomb disposal is an all encompassing term to describe the separate, but interrelated functions in the following fields:*Military:...

 officers wear heavy armor and helmets with face visors and spine protection.

Overview

Ballistic vests use layers of very strong fiber to "catch" and deform a bullet, mushrooming it into a dish shape, and spreading its force over a larger portion of the vest fiber. The vest absorbs the energy from the deforming bullet, bringing it to a stop before it can completely penetrate the textile matrix. Some layers may be penetrated but as the bullet deforms, the energy is absorbed by a larger and larger fiber area.

While a vest can prevent bullet penetration, the vest and wearer still absorb the bullet's energy. Even without penetration, modern pistol bullets contain enough energy to cause blunt force trauma
Blunt trauma
In medical terminology, blunt trauma, blunt injury, non-penetrating trauma or blunt force trauma refers to a type of physical trauma caused to a body part, either by impact, injury or physical attack; the latter usually being referred to as blunt force trauma...

 under the impact point. Vest specifications will typically include both penetration resistance requirements and limits on the amount of impact energy that is delivered to the body.

Vests designed for bullets offer little protection against blows from sharp implements, such as knives, arrows or ice picks, or from bullets manufactured of non-deformable materials, i.e., those containing a steel core instead of lead. This is because the impact force of these objects stays concentrated in a relatively small area, allowing them to puncture the fiber layers of most bullet-resistant fabrics.

Textile vests may be augmented with metal (steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

 or titanium
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....

), ceramic or polyethylene plates that provide extra protection to vital areas. These hard armor plates have proven effective against all handgun bullets and a range of rifles. These upgraded ballistic vests have become standard in military use, as soft body armor vests are ineffective against military rifle rounds. Corrections officers and other law enforcement officers often wear vests which are designed specifically against bladed weapons and sharp objects. These vests may incorporate coated and laminated para-aramid
Aramid
Aramid fibers are a class of heat-resistant and strong synthetic fibers. They are used in aerospace and military applications, for ballistic rated body armor fabric and ballistic composites, in bicycle tires, and as an asbestos substitute. The name is a portmanteau of "aromatic polyamide"...

 textiles or metallic components.

Late Middle Ages

In 1538, Francesco Maria della Rovere
Francesco Maria I della Rovere
Francesco Maria I della Rovere was an Italian condottiero, who was Duke of Urbino from 1508 until 1538.- Biography :...

 commissioned Filippo Negroli
Filippo Negroli
Filippo Negroli was an armourer from Milan. He was renowned as being extremely skilled, and may be considered the most famous armourer of all time. Working together with his younger brothers Giovan Battista and Francesco in the Negroli family workshop headed by their father Gian Giacomo Negroli...

 to create a bulletproof vest. In 1561, Maximilian II, Holy Roman Emperor
Maximilian II, Holy Roman Emperor
Maximilian II was king of Bohemia and king of the Romans from 1562, king of Hungary and Croatia from 1563, emperor of the Holy Roman Empire of the German Nation from 1564 until his death...

 is recorded as testing his armor against gun-fire. Similarly, in 1590 Sir Henry Lee
Henry Lee of Ditchley
Sir Henry Lee KG , of Ditchley, was Master of the Ordnance under Queen Elizabeth I of England.-Life:Lee became Queen Elizabeth I’s champion in 1570 and was appointed Master of the Royal Armouries in 1580, an office which he held until his death...

 expected his Greenwich armor to be "pistol proof". Its actual effectiveness was controversial at the time. The etymology
Etymology
Etymology is the study of the history of words, their origins, and how their form and meaning have changed over time.For languages with a long written history, etymologists make use of texts in these languages and texts about the languages to gather knowledge about how words were used during...

 of "bullet
Bullet
A bullet is a projectile propelled by a firearm, sling, or air gun. Bullets do not normally contain explosives, but damage the intended target by impact and penetration...

" and the adjective form of "proof" in the late 16th century would suggest that the term "bulletproof" originated shortly thereafter to identify a dent on the armor which proved it would resist bullet penetration. During the English Civil War
English Civil War
The English Civil War was a series of armed conflicts and political machinations between Parliamentarians and Royalists...

 Oliver Cromwell
Oliver Cromwell
Oliver Cromwell was an English military and political leader who overthrew the English monarchy and temporarily turned England into a republican Commonwealth, and served as Lord Protector of England, Scotland, and Ireland....

's Ironside cavalry
Ironside (cavalry)
The Ironsides were troopers in the Parliamentarian cavalry formed by English political leader Oliver Cromwell in the 17th century, during the English Civil War. The name came from "Old Ironsides", one of Cromwell's nicknames...

 were equipped with Capeline
Capeline
Capeline is the name given to two distinct types of post-Renaissance helmetThe first was a steel skullcap usually worn by archers that continued to be worn into the 17th century by musketeers and horsemen who wished to wear fashionable broad-brimmed hats but also retain some level of protection...

 helmets and musket-proof cuirass
Cuirass
A cuirass is a piece of armour, formed of a single or multiple pieces of metal or other rigid material, which covers the front of the torso...

es which consisted of two layers of armor plate (in later studies involving X-ray a third layer was discovered which was placed in between the outer and inner layer). The outer layer was designed to absorb the bullet's energy and the thicker inner layer stopped further penetration. The armor would be left badly dented but still serviceable. One of the first recorded descriptions of soft armor use was found in medieval Japan, with the armor having been manufactured from silk.

1800s–1930s

There is an account in The Cork Examiner of a tailor in Dublin who intended to create and sell bulletproof vests in December 1847.

Myeonje baegab

Another soft ballistic vest, Myeonje baegab, was invented in Joseon
Joseon Dynasty
Joseon , was a Korean state founded by Taejo Yi Seong-gye that lasted for approximately five centuries. It was founded in the aftermath of the overthrow of the Goryeo at what is today the city of Kaesong. Early on, Korea was retitled and the capital was relocated to modern-day Seoul...

, Korea in the 1860s shortly after the French campaign against Korea
French Campaign against Korea, 1866
The French campaign against Korea of 1866 is also known as Byeong-in yangyo . It refers to the French invasion of Ganghwa Island in Korea in retaliation for the earlier execution by Korea's Joseon Dynasty of French Catholic priests proselytizing in that country...

. Heungseon Daewongun ordered development of bullet-proof armor because of increasing threats from Western armies. Kim Gi-Doo and Gang Yoon found that cotton could protect against bullets if 13 layers of cotton fabric were used. The vests were used in battle during the United States expedition to Korea, when the US Navy attacked Ganghwa Island
Ganghwa Island
Ganghwa Island is an island in the estuary of the Han River, on the west coast of South Korea. Ganghwa Island is separated from Gimpo, on the mainland, by a narrow channel, which is spanned by two bridges. The main channel of the Han River separates the island from Gaeseong in North Korea.About...

 in 1871. The US Army captured one of the vests and took it to the US, where it was stored at the Smithsonian Museum until 2007. The vest has since been sent back to Korea and is currently on display to the public.

Ned Kelly's Ploughboard Ballistic Suit

One of the early instances of ballistic armor being used was on Sunday 28 June 1880, when a gang of Australian bushranger
Bushranger
Bushrangers, or bush rangers, originally referred to runaway convicts in the early years of the British settlement of Australia who had the survival skills necessary to use the Australian bush as a refuge to hide from the authorities...

s led by Ned Kelly
Ned Kelly
Edward "Ned" Kelly was an Irish Australian bushranger. He is considered by some to be merely a cold-blooded cop killer — others, however, consider him to be a folk hero and symbol of Irish Australian resistance against the Anglo-Australian ruling class.Kelly was born in Victoria to an Irish...

 had made armour from plough
Plough
The plough or plow is a tool used in farming for initial cultivation of soil in preparation for sowing seed or planting. It has been a basic instrument for most of recorded history, and represents one of the major advances in agriculture...

 blades. By this time the Victorian Government had a reward for the capture of a member of the Kelly Gang at £8,000 (equivalent to two million Australian dollars in 2005). One of the stated aims of Kelly was the establishment of a Republic in North East Victoria. Each of the four Kelly gang members had fought against a siege at a hotel clad in suits of armour made from the mouldboards of ploughs. The maker's stamp (Lennon Number 2 Type) was found inside several of the plates. The armour covered their torsos, upper arms, and upper legs, and was worn with a helmet. The suits were rough made by a creek bed using a makeshift forge and a stringy-bark log as a muffled anvil. They had a mass of around 44 kg (96 lb), making the wearer a spectacular sight yet proved too unwieldy during a police raid at Glenrowan
Glenrowan, Victoria
Glenrowan is a small town located in the Wangaratta Local Government Area of Victoria, Australia. It is 184 kilometres north-east of Melbourne and 14 kilometres from Wangaratta and located near the Warby Ranges and Mount Glenrowan...

. Their armour endured many hits with none penetrating, but eventually was of no use as the suits lacked protection for the legs and hands.

Dr. George Emery Goodfellow and Kazimierz Żegleń

During the early 1880s, Dr. George Emery Goodfellow of Arizona began investigating silk vests resembling medieval gambeson
Gambeson
A gambeson is a padded defensive jacket, worn as armour separately, or combined with mail or plate armour. Gambeson were produced with a sewing technique called quilting. Usually constructed of linen or wool, the stuffing varied, and could be for example scrap cloth or horse hair...

s, which used 18 to 30 layers of cloth to protect the wearers from arrow penetration. Dr. Goodfellow's interest in silk bulletproof vests arose after he learned about several cases where silk fabric slowed the impact of bullets in the bodies of people who were shot.
Fr. Casimir Zeglen
Casimir Zeglen
Kazimierz Żegleń , born in 1869 near Tarnopol , invented the first bulletproof vest. At the age of 18 he entered the Resurrectionist Order in Lwow . In 1890, he moved to the United States. In 1893, after the assassination of Carter Harrison, Sr., the mayor of Chicago, he invented the first...

 used Goodfellow's findings to develop a bulletproof vest made of silk fabric at the end of the 19th century, which could stop the relatively slow rounds from black powder
Gunpowder
Gunpowder, also known since in the late 19th century as black powder, was the first chemical explosive and the only one known until the mid 1800s. It is a mixture of sulfur, charcoal, and potassium nitrate - with the sulfur and charcoal acting as fuels, while the saltpeter works as an oxidizer...

 handguns. The vests cost $800 USD each in 1914, a small fortune at the time. On 28 June 1914, Archduke Franz Ferdinand of Austria
Archduke Franz Ferdinand of Austria
Franz Ferdinand was an Archduke of Austria-Este, Austro-Hungarian and Royal Prince of Hungary and of Bohemia, and from 1889 until his death, heir presumptive to the Austro-Hungarian throne. His assassination in Sarajevo precipitated Austria-Hungary's declaration of war against Serbia...

, heir to the throne of Austria-Hungary
Austria-Hungary
Austria-Hungary , more formally known as the Kingdoms and Lands Represented in the Imperial Council and the Lands of the Holy Hungarian Crown of Saint Stephen, was a constitutional monarchic union between the crowns of the Austrian Empire and the Kingdom of Hungary in...

, was wearing a silk bulletproof vest when he was attacked by a gun-wielding assassin. Because he was shot in the neck above the vest, the vest did not protect him. A similar vest, made by Jan Szczepanik
Jan Szczepanik
Jan Szczepanik was a Polish inventor....

 in 1901, saved the life of Alfonso XIII of Spain
Alfonso XIII of Spain
Alfonso XIII was King of Spain from 1886 until 1931. His mother, Maria Christina of Austria, was appointed regent during his minority...

 when he was shot by an attacker.

WWI armor and gangster vests

During World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

, the United States developed several types of body armor, including the chrome nickel steel Brewster Body Shield, which consisted of a breastplate and a headpiece and could withstand Lewis Gun
Lewis Gun
The Lewis Gun is a World War I–era light machine gun of American design that was perfected and widely used by the British Empire. It was first used in combat in World War I, and continued in service with a number of armed forces through to the end of the Korean War...

 bullets at 2700 ft/s (823 m/s), but was clumsy and heavy at 40 lb (18.1 kg). A scaled waistcoat
Waistcoat
A waistcoat or vest is a sleeveless upper-body garment worn over a dress shirt and necktie and below a coat as a part of most men's formal wear, and as the third piece of the three-piece male business suit.-Characteristics and use:...

 of overlapping steel scales fixed to a leather lining was also designed; this armor weighed 11 lb (5 kg), fit close to the body, and was considered more comfortable.

During the late 1920s through the early 1930s
Social issues of the 1920s
The 1920s was the rise of a variety of social issues amidst a rapidly changing world. Conflicts arose concerning what was considered acceptable and respectable and what ought to be proscribed or made illegal...

, gunmen from criminal gangs in the United States began wearing less-expensive vests made from thick layers of cotton padding and cloth. These early vests could absorb the impact of handgun rounds such as .22 Long Rifle
.22 Long Rifle
The .22 Long Rifle rimfire cartridge is a long established variety of ammunition, and in terms of units sold is still by far the most common in the world today. The cartridge is often referred to simply as .22 LR and various rifles, pistols, revolvers, and even some smoothbore shotguns have...

, .25 ACP
.25 ACP
The .25 ACP centerfire pistol cartridge is a semi-rimmed, straight-walled pistol cartridge introduced by John Browning in 1905 alongside the Fabrique Nationale model 1905 pistol...

, .32 S&W Long
.32 S&W Long
The .32 S&W Long is a straight-walled, centerfire, rimmed handgun cartridge, based on the earlier .32 S&W cartridge. It was introduced in 1896 for Smith & Wesson's first-model Hand Ejector revolver...

, .32 S&W
.32 S&W
The .32 S&W cartridge was introduced in 1878 for the Smith & Wesson model 1½ revolver. It was originally designed as a black powder cartridge.The .32 S&W was offered to the public as a light, defense cartridge, for "card table" distances....

, .380 ACP
.380 ACP
The .380 ACP pistol cartridge is a rimless, straight-walled pistol cartridge developed by firearms designer John Browning. The cartridge headspaces on the mouth of the case. It was introduced in 1908 by Colt, and has been a popular self-defense cartridge ever since...

, and .45 ACP
.45 ACP
The .45 ACP , also known as the .45 Auto by C.I.P., is a cartridge designed by John Browning in 1904, for use in his prototype Colt semi-automatic .45 pistol and eventually the M1911 pistol adopted by the United States Army in 1911.-Design and history:The U.S...

 traveling at speeds of up to 300 m/s. To overcome these vests, law enforcement agents such as the FBI
Federal Bureau of Investigation
The Federal Bureau of Investigation is an agency of the United States Department of Justice that serves as both a federal criminal investigative body and an internal intelligence agency . The FBI has investigative jurisdiction over violations of more than 200 categories of federal crime...

 began using the newer and more powerful .38 Super
.38 Super
The .38 Super or .38 Super Automatic is a pistol cartridge that fires a diameter bullet. The Super was introduced in the late 1920s as a higher pressure loading of the .38 ACP or .38 Auto. The old .38 ACP propelled a bullet at . The improved .38 Super Auto pushed the same bullet at...

, and later the .357 Magnum
.357 Magnum
The .357 S&W Magnum , or simply .357 Magnum, is a revolver cartridge created by Elmer Keith, Phillip B. Sharpe, Colonel D. B. Wesson of firearms manufacturer Smith & Wesson, and Winchester. It is based upon Smith & Wesson's earlier .38 Special cartridge. The .357 Magnum cartridge was introduced in...

 cartridge.

World War II

In the early stages of World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

, the United States designed body armor for infantry
Infantry
Infantrymen are soldiers who are specifically trained for the role of fighting on foot to engage the enemy face to face and have historically borne the brunt of the casualties of combat in wars. As the oldest branch of combat arms, they are the backbone of armies...

men, but most models were too heavy and mobility-restricting to be useful in the field and incompatible with existing required equipment. The military diverted its research efforts to developing flak jacket
Flak jacket
thumb|300px|The two components of an obsolete British military flak vest. On the left, the nylon vest. On the right, the several layers of [[ballistic nylon]] that provide the actual protection...

s for aircraft crews. These jackets were made of nylon
Nylon
Nylon is a generic designation for a family of synthetic polymers known generically as polyamides, first produced on February 28, 1935, by Wallace Carothers at DuPont's research facility at the DuPont Experimental Station...

 fabric and capable of stopping flak and shrapnel, but were not designed to stop bullets.
The British Army issued Medical Research Council body armor, as did the Canadian Army, in northwestern Europe, in the latter case primarily to medical personnel of the 2nd Canadian Infantry Division. The Japanese army produced a few types of infantry body armor during World War II, but these did not see much use. Near the middle of 1944, development of infantry body armor in the United States restarted. Several vests were produced for the US military, including but not limited to the T34, the T39, the T62E1, and the M12.

The Red Army
Red Army
The Workers' and Peasants' Red Army started out as the Soviet Union's revolutionary communist combat groups during the Russian Civil War of 1918-1922. It grew into the national army of the Soviet Union. By the 1930s the Red Army was among the largest armies in history.The "Red Army" name refers to...

 used several types of body armor, including the SN-42
SN-42
There were several models of body armor in the Red Army, called SN-38, SN-39, SN-40, SN-40A, and SN-42. The number denotes the design year. All were combat tested, but only the SN-42 was put in production...

 ( "Stalynoi Nagrudnik" is Russian for "steel breastplate", and the number denotes the design year). All were tested, but only the SN-42 was put in production. It consisted of two pressed steel plates that protected the front torso and groin. The plates were 2 mm thick and weighed 3.5 kg (7.7 lb). This armor was supplied to SHISBr (assault engineers) and to Tankodesantniki
Tank desant
Tank desant is a military combined arms tactic, where infantry soldiers ride into an attack on tanks, then dismount to fight on foot in the final phase of the assault...

 (infantry that rode on tanks) of some tank brigades. The SN armor protected wearers from 9 mm bullets fired by an MP 40 at around 100 meters, which made it useful in urban battles such as the Battle of Stalingrad
Battle of Stalingrad
The Battle of Stalingrad was a major battle of World War II in which Nazi Germany and its allies fought the Soviet Union for control of the city of Stalingrad in southwestern Russia. The battle took place between 23 August 1942 and 2 February 1943...

. However, the SN's weight made it impractical for infantry in the open.

The United States developed a vest using Doron Plate
Doron Plate
Doron Plate is a strong fiberglass-based laminate that was first used by the United States military as personal body armor for infantry in the Battle of Okinawa in 1945. The plates were approximately 1/8 inch thick and cut into five inch squares then inserted into pockets on a nylon vest that...

, a fiberglass
Fiberglass
Glass fiber is a material consisting of numerous extremely fine fibers of glass.Glassmakers throughout history have experimented with glass fibers, but mass manufacture of glass fiber was only made possible with the invention of finer machine tooling...

-based laminate
Fibre-reinforced plastic
Fibre-reinforced plastic is a composite material made of a polymer matrix reinforced with fibres. The fibres are usually fibreglass, carbon, or aramid, while the polymer is usually an epoxy, vinylester or polyester thermosetting plastic...

. These vests were first used in the Battle of Okinawa
Battle of Okinawa
The Battle of Okinawa, codenamed Operation Iceberg, was fought on the Ryukyu Islands of Okinawa and was the largest amphibious assault in the Pacific War of World War II. The 82-day-long battle lasted from early April until mid-June 1945...

 in 1945.

1950s–1970s

During the Korean War
Korean War
The Korean War was a conventional war between South Korea, supported by the United Nations, and North Korea, supported by the People's Republic of China , with military material aid from the Soviet Union...

 several new vests were produced for the United States military, including the M-1951
M-1951 field jacket
The M-1951 field jacket was a US Army four pocket jacket made of 9-ounce wind resistant water repellent treated cotton sateen cloth in Olive Green Shade 107 . In November 1956 it was redesignated as the M-1951 field coat....

, which made use of fibre-reinforced plastic
Fibre-reinforced plastic
Fibre-reinforced plastic is a composite material made of a polymer matrix reinforced with fibres. The fibres are usually fibreglass, carbon, or aramid, while the polymer is usually an epoxy, vinylester or polyester thermosetting plastic...

 or aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....

 segments woven into a nylon
Nylon
Nylon is a generic designation for a family of synthetic polymers known generically as polyamides, first produced on February 28, 1935, by Wallace Carothers at DuPont's research facility at the DuPont Experimental Station...

 vest. These vests represented "a vast improvement on weight, but the armor failed to stop bullets and fragments very successfully," although officially they were claimed to be able to stop 7.62x25mm Tokarev pistol rounds at the muzzle. Developed by Natick Laboratories and introduced in 1967, T65-2 plate carriers were the first vests designed to hold hard ceramic plate
Ceramic plate
Ceramic plates are commonly used as inserts in soft ballistic vests. Most ceramic plates used in body armor provide National Institute of Justice Type III protection, allowing them to stop rifle bullets. Ceramic plates are a form of composite armor...

s, making them capable of stopping 7 mm rifle rounds.
These "Chicken Plates" were made of either boron carbide
Boron carbide
Boron carbide is an extremely hard boron–carbon ceramic material used in tank armor, bulletproof vests, and numerous industrial applications...

, silicon carbide
Silicon carbide
Silicon carbide , also known as carborundum, is a compound of silicon and carbon with chemical formula SiC. It occurs in nature as the extremely rare mineral moissanite. Silicon carbide powder has been mass-produced since 1893 for use as an abrasive...

, or aluminium oxide
Aluminium oxide
Aluminium oxide is an amphoteric oxide with the chemical formula 23. It is commonly referred to as alumina, or corundum in its crystalline form, as well as many other names, reflecting its widespread occurrence in nature and industry...

. They were issued to the crew of low-flying aircraft, such as the UH-1 and UC-123, during the Vietnam War
Vietnam War
The Vietnam War was a Cold War-era military conflict that occurred in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. This war followed the First Indochina War and was fought between North Vietnam, supported by its communist allies, and the government of...

.

In 1969, American Body Armor was founded and began to produce a patented combination of quilted nylon faced with multiple steel plates. This armor configuration was marketed to American law enforcement agencies by Smith & Wesson
Smith & Wesson
Smith & Wesson is the largest manufacturer of handguns in the United States. The corporate headquarters is in Springfield, Massachusetts. Founded in 1852, Smith & Wesson's pistols and revolvers have become standard issue to police and armed forces throughout the world...

 under the trade name
Trade name
A trade name, also known as a trading name or a business name, is the name which a business trades under for commercial purposes, although its registered, legal name, used for contracts and other formal situations, may be another....

 "Barrier Vest." The Barrier Vest was the first police vest to gain wide use during high threat police operations. In the mid-1970s, DuPont
DuPont
E. I. du Pont de Nemours and Company , commonly referred to as DuPont, is an American chemical company that was founded in July 1802 as a gunpowder mill by Eleuthère Irénée du Pont. DuPont was the world's third largest chemical company based on market capitalization and ninth based on revenue in 2009...

 introduced Kevlar
Kevlar
Kevlar is the registered trademark for a para-aramid synthetic fiber, related to other aramids such as Nomex and Technora. Developed at DuPont in 1965, this high strength material was first commercially used in the early 1970s as a replacement for steel in racing tires...

 synthetic fiber, which was woven into a fabric and layered. Immediately Kevlar was incorporated into a National Institute of Justice
National Institute of Justice
The National Institute of Justice is the research, development and evaluation agency of the United States Department of Justice. NIJ, along with the Bureau of Justice Statistics , Bureau of Justice Assistance , Office of Juvenile Justice and Delinquency Prevention , Office for Victims of Crime ,...

 (NIJ) evaluation program to provide lightweight, concealable body armor to a test pool of American law enforcement officers to ascertain if everyday concealable wearing was possible. Lester Shubin
Lester Shubin
Lester D. Shubin was a researcher who developed Kevlar for the use in ballistic vests. Kevlar's use in ballistic vests was later expanded for use in all types of personal armor.-Life:...

, a program manager at the NIJ, managed this law enforcement feasibility study within a few selected large police agencies, and quickly determined that Kevlar body armor could be comfortably worn by police daily, and would save lives.

In 1975 Richard A. Armellino, the founder of American Body Armor, marketed an all Kevlar vest called the K-15, consisting of 15 layers of Kevlar that also included a 5" × 8" ballistic steel "Shok Plate" positioned vertically over the heart and was issued US Patent #3,971,072 for this innovation. Similarly sized and positioned "trauma plates" are still used today on the front ballistic panels of most concealable vests, reducing blunt trauma and increasing ballistic protection in the center-mass heart/sternum area.

In 1976, Richard Davis, founder of Second Chance Body Armor, designed the company's first all-Kevlar vest, the Model Y. The lightweight, concealable vest industry was launched and a new form of daily protection for the modern police officer was quickly adapted. By the mid-to-late 1980s, an estimated 1/3 to 1/2 of police patrol officers wore concealable vests daily. By 2006, more than 2,000 documented police vest "saves" were recorded, validating the success and efficiency of lightweight concealable body armor as a standard piece of everyday police equipment.

1990s–2000s

Kevlar soft armor had its shortcomings because if "large fragments or high velocity bullets hit the vest, the energy could cause life-threatening, blunt trauma injuries" in selected, vital areas. Ranger Body Armor
Ranger Body Armor
Ranger Body Armor is a U.S. Military issue ballistic vest that was designed for, and used chiefly by, military personnel of the U.S. Army's 75th Ranger Regiment, beginning in the early 1990s, and possibly into the early 2000s...

 was developed for the American military in 1991. Although it was the second modern US body armor that was able to stop rifle caliber rounds and still be light enough to be worn by infantry soldiers in the field, it still had its flaws: "it was still heavier than the concurrently issued PASGT (Personal Armor System for Ground Troops) anti-fragmentation armor worn by regular infantry and ... did not have the same degree of ballistic protection around the neck and shoulders." The format of Ranger Body Armor (and more recent body armor issued to US special operations units) highlights the trade-offs between force protection and mobility that modern body armor forces organizations to address.

Newer armor issued by the United States armed forces
United States armed forces
The United States Armed Forces are the military forces of the United States. They consist of the Army, Navy, Marine Corps, Air Force, and Coast Guard.The United States has a strong tradition of civilian control of the military...

 to large numbers of troops includes the United States Army
United States Army
The United States Army is the main branch of the United States Armed Forces responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military, and is one of seven U.S. uniformed services...

's Improved Outer Tactical Vest
Improved Outer Tactical Vest
The Improved Outer Tactical Vest, or IOTV, is an enhanced version of, and a replacement for, the older Outer Tactical Vest variant of the Interceptor body armor, as fielded by the United States Army...

 and the United States Marine Corps
United States Marine Corps
The United States Marine Corps is a branch of the United States Armed Forces responsible for providing power projection from the sea, using the mobility of the United States Navy to deliver combined-arms task forces rapidly. It is one of seven uniformed services of the United States...

  Modular Tactical Vest
Modular Tactical Vest
The Modular Tactical Vest or is a bulletproof vest originally adopted by the United States Marine Corps in 2006. The MTV was designed as a solution to shortcomings in the current, decade-old interceptor body armor and was selected after a rigorous proposal and examination process by the Marine...

. All of these systems are designed with the vest intended to provide protection from fragments and pistol rounds. Hard ceramic plates such as the Small Arms Protective Insert as used with Interceptor Body Armor, are worn to protect the vital organs from higher level threats. These threats mostly take the form of high velocity and armor-piercing rifle rounds. Similar types of protective equipment have been adopted by modern armed forces the world over.

Since the 1970s, several new fibers and construction methods for bulletproof fabric have been developed besides woven Kevlar, such as DSM's Dyneema, Honeywell's Gold Flex
Gold Flex
Gold Flex is a fabric manufactured by Honeywell from synthetic fiber and often used in ballistic vests and body armor.Gold Flex is a laminated fabric consisted of crossed-laid fibers.- External links :* manufacturer of the Gold Flex fabric.*.*...

 and Spectra, Teijin Twaron's Twaron
Twaron
Twaron is the brandname of Teijin Aramid for a para-aramid. It is a heat-resistant and strong synthetic fibre developed in the early 1970s by the Dutch company AKZO, division Enka, later Akzo Industrial Fibers. The research name of the para-aramid fibre was originally Fiber X, but it was soon...

, Pinnacle Armor's Dragon Skin
Dragon Skin (body armor)
Dragon Skin is a type of ballistic vest made by Pinnacle Armor. It is currently produced in Fresno, California. Its characteristic two-inch-wide circular discs overlap like scale armor, creating a flexible vest that allows a good range of motion and can allegedly absorb a high number of hits...

, and Toyobo's Zylon
Zylon
Zylon is a trademarked name for a range of thermoset liquid crystalline polyoxazole...

. These newer materials are advertised as being lighter, thinner and more resistant than Kevlar, although they are much more expensive. The US military has developed body armor for the working dog
Dogs in warfare
Dogs in warfare have a long history starting in ancient times. From 'war dogs' trained in combat to their use as scouts, sentries and trackers, their uses have been varied and some continue to exist in modern military usage.-History:...

s who aid GIs in battle.

Performance standards

Due to the various types of projectile, it is often inaccurate to refer to a particular product as "bulletproof" because this implies that it will protect against any and all threats. Instead, the term bullet resistant is generally preferred.

Body armor standards are regional. Around the world ammunition varies and as a result the armor testing must reflect the threats found locally. Law enforcement statistics show that many shootings where officers are injured or killed involve the officer's own weapon. As a result, each law enforcement agency or para-military organization will have their own standard for armor performance if only to ensure that their armor protects them from their own weapons. While many standards exist, a few standards are widely used as models. The US National Institute of Justice
National Institute of Justice
The National Institute of Justice is the research, development and evaluation agency of the United States Department of Justice. NIJ, along with the Bureau of Justice Statistics , Bureau of Justice Assistance , Office of Juvenile Justice and Delinquency Prevention , Office for Victims of Crime ,...

 ballistic and stab documents are examples of broadly accepted standards. In addition to the NIJ, the UK Home Office Scientific Development Branch
HOTA
HOTA is an acronym for Home Office Type Approval, a testing and certification process by the Home Office in the United Kingdom that speed cameras must pass before evidence from them can be admissible in UK courts by way of certification in accordance with Section 20 of the Road Traffic Offenders...

 (HOSDB – formerly the Police Scientific Development Branch (PSDB)) standards are used by a number of other countries and organizations. These "model" standards are usually adapted by other counties by incorporation of the basic test methodologies with modification of the bullets that are required for test.
NIJ Standard-0101.06 has specific performance standards
Standardization
Standardization is the process of developing and implementing technical standards.The goals of standardization can be to help with independence of single suppliers , compatibility, interoperability, safety, repeatability, or quality....

 for bullet resistant vests used by law enforcement. This rates vests on the following scale against penetration and also blunt trauma protection (deformation):
Armor Level Protection
Type I
(.22 LR
.22 Long Rifle
The .22 Long Rifle rimfire cartridge is a long established variety of ammunition, and in terms of units sold is still by far the most common in the world today. The cartridge is often referred to simply as .22 LR and various rifles, pistols, revolvers, and even some smoothbore shotguns have...

; .380 ACP
.380 ACP
The .380 ACP pistol cartridge is a rimless, straight-walled pistol cartridge developed by firearms designer John Browning. The cartridge headspaces on the mouth of the case. It was introduced in 1908 by Colt, and has been a popular self-defense cartridge ever since...

)
This armor would protect against 2.6 g
Gram
The gram is a metric system unit of mass....

 (40 gr) .22 Long Rifle
.22 Long Rifle
The .22 Long Rifle rimfire cartridge is a long established variety of ammunition, and in terms of units sold is still by far the most common in the world today. The cartridge is often referred to simply as .22 LR and various rifles, pistols, revolvers, and even some smoothbore shotguns have...

 Lead Round Nose (LR LRN) bullets at a velocity of 329 m/s (1080 ft/s ± 30 ft/s) and 6.2 g (95 gr) .380 ACP
.380 ACP
The .380 ACP pistol cartridge is a rimless, straight-walled pistol cartridge developed by firearms designer John Browning. The cartridge headspaces on the mouth of the case. It was introduced in 1908 by Colt, and has been a popular self-defense cartridge ever since...

 Full Metal Jacketed Round Nose (FMJ RN) bullets at a velocity of 322 m/s (1055 ft/s ± 30 ft/s). It is no longer part of the standard.
Type IIA
(9 mm; .40 S&W
.40 S&W
The .40 S&W is a rimless pistol cartridge developed jointly by major American firearms manufacturers Winchester and Smith & Wesson. The .40 S&W was developed from the ground up as a law enforcement cartridge designed to duplicate performance of the FBI's reduced velocity 10mm cartridge which could...

; .45 ACP
.45 ACP
The .45 ACP , also known as the .45 Auto by C.I.P., is a cartridge designed by John Browning in 1904, for use in his prototype Colt semi-automatic .45 pistol and eventually the M1911 pistol adopted by the United States Army in 1911.-Design and history:The U.S...

)
New armor protects against 8 g (124 gr) 9x19mm Parabellum Full Metal Jacketed Round Nose (FMJ RN) bullets at a velocity of 373 m/s ± 9.1 m/s (1225 ft/s ± 30 ft/s); 11.7 g (180 gr) .40 S&W
.40 S&W
The .40 S&W is a rimless pistol cartridge developed jointly by major American firearms manufacturers Winchester and Smith & Wesson. The .40 S&W was developed from the ground up as a law enforcement cartridge designed to duplicate performance of the FBI's reduced velocity 10mm cartridge which could...

 Full Metal Jacketed (FMJ) bullets at a velocity of 352 m/s ± 9.1 m/s (1155 ft/s ± 30 ft/s) and 14.9 g (230 gr) .45 ACP
.45 ACP
The .45 ACP , also known as the .45 Auto by C.I.P., is a cartridge designed by John Browning in 1904, for use in his prototype Colt semi-automatic .45 pistol and eventually the M1911 pistol adopted by the United States Army in 1911.-Design and history:The U.S...

 Full Metal Jacketed (FMJ) bullets at a velocity of 275 m/s ± 9.1 m/s (900 ft/s ± 30 ft/s). Conditioned armor protects against 8 g (124 gr) 9 mm FMJ RN bullets at a velocity of 355 m/s ± 9.1 m/s (1165 ft/s ± 30 ft/s); 11.7 g (180 gr) .40 S&W FMJ bullets at a velocity of 325 m/s ± 9.1 m/s (1065 ft/s ± 30 ft/s) and 14.9 g (230 gr) .45 ACP Full Metal Jacketed (FMJ) bullets at a velocity of 259 m/s ± 9.1 m/s (850 ft/s ± 30 ft/s). It also provides protection against the threats mentioned in [Type I].
Type II
(9 mm; .357 Magnum
.357 Magnum
The .357 S&W Magnum , or simply .357 Magnum, is a revolver cartridge created by Elmer Keith, Phillip B. Sharpe, Colonel D. B. Wesson of firearms manufacturer Smith & Wesson, and Winchester. It is based upon Smith & Wesson's earlier .38 Special cartridge. The .357 Magnum cartridge was introduced in...

)
New armor protects against 8 g (124 gr) 9 mm FMJ RN bullets at a velocity of 398 m/s ± 9.1 m/s (1305 ft/s ± 30 ft/s) and 10.2 g (158 gr) .357 Magnum Jacketed Soft Point bullets at a velocity of 436 m/s ± 9.1 m/s (1430 ft/s ± 30 ft/s). Conditioned armor protects against 8 g (124 gr) 9 mm FMJ RN bullets at a velocity of 379 m/s ±9.1 m/s (1245 ft/s ± 30 ft/s) and 10.2 g (158 gr) .357 Magnum Jacketed Soft Point bullets at a velocity of 408 m/s ±9.1 m/s (1340 ft/s ± 30 ft/s). It also provides protection against the threats mentioned in [Types I and IIA].
Type IIIA
(.357 SIG
.357 SIG
The .357 SIG pistol cartridge is the product of Swiss-German firearms manufacturer SIG-Sauer, in cooperation with the American ammunition manufacturer Federal Cartridge. While it is based on a .40 S&W case necked down to accept bullets, the .357 SIG brass is slightly longer...

; .44 Magnum
.44 Magnum
The .44 Remington Magnum, or simply .44 Magnum, is a large-bore cartridge originally designed for revolvers. After introduction, it was quickly adopted for carbines and rifles...

)
New armor protects against 8.1 g (125 gr) .357 SIG FMJ Flat Nose (FN) bullets at a velocity of 448 m/s ± 9.1 m/s (1470 ft/s ± 30 ft/s) and 15.6 g (240 gr) .44 Magnum Semi Jacketed Hollow Point (SJHP) bullets at a velocity of 436 m/s (1430 ft/s ± 30 ft/s). Conditioned armor protects against 8.1 g (125 gr) .357 SIG FMJ Flat Nose (FN) bullets at a velocity of 430 m/s ± 9.1 m/s (1410 ft/s ± 30 ft/s) and 15.6 g (240 gr) .44 Magnum Semi Jacketed Hollow Point (SJHP) bullets at a velocity of 408 m/s ± 9.1 m/s (1340 ft/s ± 30 ft/s). It also provides protection against most handgun threats, as well as the threats mentioned in [Types I, IIA, and II].
Type III
(Rifles)
Conditioned armor protects against 9.6 g (148 gr) 7.62x51mm NATO M80 ball bullets at a velocity of 847 m/s ± 9.1 m/s (2780 ft/s ± 30 ft/s). It also provides protection against the threats mentioned in [Types I, IIA, II, and IIIA].
Type IV
(Armor Piercing Rifle)
Conditioned armor protects against 10.8 g (166 gr) .30-06 Springfield
.30-06 Springfield
The .30-06 Springfield cartridge or 7.62×63mm in metric notation, was introduced to the United States Army in 1906 and standardized, and was in use until the 1960s and early 1970s. It replaced the .30-03, 6 mm Lee Navy, and .30 US Army...

 M2 armor-piercing (AP) bullets at a velocity of 878 m/s ± 9.1 m/s (2880 ft/s ± 30 ft/s). It also provides at least single hit protection against the threats mentioned in [Types I, IIA, II, IIIA, and III].

NIJ standards are used for law enforcement armors. The US and NATO military armor designs are tested using a standard set of test methods under ARMY MIL-STD-662F and STANAG 2920 Ed2. This approach defines the test process under the 662F/2920 standard. Each armor program can select a unique series of projectiles and velocities as required. The DOD and MOD armor programs-of-record (MTV for example)procure armor using these test standards. In addition, special requirements can be defined under this process for armors for flexible rifle protection, fragment protection for the extremities, etc. These military procurement requirements do not relate to NIJ, HOSDB or ISO law enforcement armor standards, test methods, garment size, projectiles or velocities.

In addition to the NIJ and HOSDB law enforcement armor standards, other important standards include: German Police TR-Technische Richtlinie; Draft ISO
International Organization for Standardization
The International Organization for Standardization , widely known as ISO, is an international standard-setting body composed of representatives from various national standards organizations. Founded on February 23, 1947, the organization promulgates worldwide proprietary, industrial and commercial...

 prEN ISO 14876; and Underwriters Laboratories
Underwriters Laboratories
Underwriters Laboratories Inc. is an independent product safety certification organization. Established in 1894, the company has its headquarters in Northbrook, Illinois. UL develops standards and test procedures for products, materials, components, assemblies, tools and equipment, chiefly dealing...

 (UL Standard 752).

Textile armor is tested for both penetration resistance by bullets and for the impact energy transmitted to the wearer. The "backface signature," or transmitted impact energy, is measured by shooting armor mounted in front of a backing material, typically oil-based modeling clay. The clay is used at a controlled temperature and verified for impact flow before testing. After the armor is impacted with the test bullet, the vest is removed from the clay and the depth of the indentation in the clay is measured.

The backface signature allowed by different test standards can be difficult to compare. Both the clay materials and the bullets used for the test are not common. In general the British, German and other European standards allow 20–25 mm of backface signature, while the US-NIJ standards allow for 44 mm, which can potentially cause internal injury. The allowable backface signature for body armor has been controversial from its introduction in the first NIJ test standard and the debate as to the relative importance of penetration-resistance vs. backface signature continues in the medical and testing communities.

In general a vest's textile material temporarily degrades when wet. Neutral water at room temp does not affect para-aramid or UHMWPE but acidic, basic and some other solutions can permanently reduce para-aramid fiber tensile strength. (As a result of this, the major test standards call for wet testing of textile armor.) Mechanisms for this wet loss of performance are not known. Vests that will be tested after ISO type water immersion tend to have heat sealed enclosures and those that are tested under NIJ type water spray methods tend to have water resistant enclosures.

From 2003 to 2005, a large study of the environmental degradation of Zylon armor was undertaken by the US-NIJ. This concluded that water, long-term use, and temperature exposure significantly affect tensile strength and the ballistic performance of PBO or Zylon fiber. This NIJ study on vests returned from the field demonstrated that environmental effects on Zylon resulted in ballistic failures under standard test conditions.

Ballistic testing V50 and V0

Measuring the ballistic performance of armor is based on determining the kinetic energy
Kinetic energy
The kinetic energy of an object is the energy which it possesses due to its motion.It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes...

 of a bullet at impact (Ek = ½ mv2). Because the energy of a bullet is a key factor in its penetrating capacity, velocity is used as the primary independent variable in ballistic testing. For most users the key measurement is the velocity at which no bullets will penetrate the armor. Measuring this zero penetration velocity (v0) must take into account variability in armor performance and test variability. Ballistic testing has a number of sources of variability: the armor, test backing materials, bullet, casing, powder, primer and the gun barrel, to name a few.

Variability reduces the predictive power of a determination of V0. If for example, the v0 of an armor design is measured to be 1600 ft/s (487.7 m/s) with a 9 mm FMJ bullet based on 30 shots, the test is only an estimate of the real v0 of this armor. The problem is variability. If the v0 is tested again with a second group of 30 shots on the same vest design, the result will not be identical.

Only a single low velocity penetrating shot is required to reduce the v0 value. The more shots made the lower the v0 will go. In terms of statistics, the zero penetration velocity is the tail end of the distribution curve. If the variability is known and the standard deviation can be calculated, one can rigorously set the V0 at a confidence interval. Test Standards now define how many shots must be used to estimate a v0 for the armor certification. This procedure defines a confidence interval of an estimate of v0. (See "NIJ and HOSDB test methods".)

v0 is difficult to measure, so a second concept has been developed in ballistic testing called v50. This is the velocity at which 50 percent of the shots go through and 50 percent are stopped by the armor. US military standard MIL-STD-662F V50 Ballistic Test define a commonly used procedure for this measurement. The goal is to get three shots that penetrate that are slower than a second faster group of three shots that are stopped by the armor. These three high stops and three low penetrations can then be used to calculate a v50 velocity.

In practice this measurement of v50 requires 1–2 vest panels and 10–20 shots. A very useful concept in armor testing is the offset velocity between the v0 and v50. If this offset has been measured for an armor design, then v50 data can be used to measure and estimate changes in v0. For vest manufacturing, field evaluation and life testing both v0 and v50 are used. However, as a result of the simplicity of making v50 measurements, this method is more important for control of armor after certification.

Military testing: fragment ballistics

After the Vietnam War, military planners developed a concept of “Casualty Reduction”. The large body of casualty data made clear that in a combat situation, fragments, not bullets, were the most important threat to soldiers. After WWII, vests were being developed and fragment testing was in its early stages. Artillery shells, mortar shells, aerial bombs, grenades, and antipersonnel mines are all fragmentation devices. They all contain a steel casing that is designed to burst into small steel fragments or shrapnel, when their explosive core detonates. After considerable effort measuring fragment size distribution from various NATO and Soviet bloc munitions, a fragment test was developed. Fragment simulators were designed, and the most common shape is a Right Circular Cylinder or RCC simulator. This shape has a length equal to its diameter. These RCC Fragment Simulation Projectiles (FSPs) are tested as a group. The test series most often includes 2 grain (0.13 g), 4 grain (0.263 g), 16 grain (1.0 g), and 64 grain (4.2 g) mass RCC FSP testing. The 2-4-16-64 series is based on the measured fragment size distributions.

The second part of “Casualty Reduction” strategy is a study of velocity distributions of fragments from munitions. Warhead explosives have blast speeds of 20000 ft/s (6,096 m/s) to 30000 ft/s (9,144 m/s). As a result, they are capable of ejecting fragments at very high speeds of over 1000 m/s (3300 ft/s), implying very high energy (where the energy of a fragment is ½ mass × velocity2, neglecting rotational energy). The military engineering data showed that, like the fragment size, the fragment velocities had characteristic distributions. It is possible to segment the fragment output from a warhead into velocity groups. For example 95% of all fragments from a bomb blast under 4 gr have a velocity of 3000 ft/s (914.4 m/s) or less. This established a set of goals for military ballistic vest design.

The random nature of fragmentation required the military vest specification to trade off mass vs. ballistic-benefit. Hard vehicle armor is capable of stopping all fragments, but military personnel can only carry a limited amount of gear and equipment, so the weight of the vest is a limiting factor in vest fragment protection. The 2-4-16-64 grain series at limited velocity can be stopped by an all-textile vest of approximately 5.4 kg/m2 (1.1 lb/ft2). In contrast to the design of vest for deformable lead bullets, fragments do not change shape; they are steel and can not be deformed by textile materials. The 2 gr FSP (the smallest fragment projectile commonly used in testing) is about the size of a grain of rice; such small fast moving fragments can potentially slip through the vest, moving between yarns. As a result fabrics optimized for fragment protection are tightly woven, although these fabrics are not as effective at stopping lead bullets.

Backing materials for ballistic testing

One of the critical requirements in soft ballistic testing is measurement of "back side signature" (i.e. energy delivered to tissue by a non-penetrating projectile) in a deformable backing material placed behind the targeted vest. The majority of military and law enforcement standards have settled on an oil/clay mixture for the backing material, known as Roma Plastilena. Although harder and less deformable than human tissue, Roma represents a “worst case” backing material when plastic deformations in the oil/clay are low (less than 20 mm). (Armor placed over a harder surface is more easily penetrated.) The oil/clay mixture of "Roma" is roughly twice the density of human tissue and therefore does not match its specific gravity, however "Roma" is a plastic material that will not recover its shape elastically, which is important for accurately measuring potential trauma through back side signature.

The selection of test backing is significant because in flexible armor, the body tissue of a wearer plays an integral part in absorbing the high energy impact of ballistic and stab events. However the human torso has a very complex mechanical behavior. Away from the rib cage and spine, the soft tissue behavior is soft and compliant. In the tissue over the sternum bone region, the compliance of the torso is significantly lower. This complexity requires very elaborate bio-morphic backing material systems for accurate ballistic and stab armor testing. A number of materials have been used to simulate human tissue in addition to Roma. In all cases, these materials are placed behind the armor during test impacts and are designed to simulate various aspects of human tissue impact behavior.

One important factor in test backing for armor is its hardness. Armor is more easily penetrated in testing when backed by harder materials, and therefore harder materials, such as Roma clay, represent more conservative test methods.
Backer type Materials Elastic/plastic Test type Specific gravity Relative hardness vs gelatin Application
Roma Plastilena Clay #1 Oil/Clay mixture Plastic Ballistic and Stab >2 Moderately hard Back face signature measurement. Used for most standard testing
10% gelatin Animal protein gel Visco-elastic Ballistic ~1 (90% water) Softer than baseline Good simulant for human tissue, hard to use, expensive. Required for FBI test methods
20% gelatin Animal protein gel Visco-elastic Ballistic ~1 (80% water) Baseline Good simulant for skeletal muscle. Provides dynamic view of event.
HOSDB-NIJ Foam Neoprene foam, EVA foam, sheet rubber Elastic Stab ~1 Slightly harder than gelatin Moderate agreement with tissue, easy to use, low in cost. Used in stab testing
Silicone gel Long chain silicone polymer Visco-elastic Biomedical ~1.2 Similar to gelatin Biomedical testing for blunt force testing, very good tissue match
Pig or Sheep animal testing Live tissue Various Research ~1 Real tissue is variable Very complex, requires ethical review for approval

Backing materials for stab armor testing

Stab and spike armor standards have been developed using 3 different backing materials. The Draft EU norm calls out Roma clay, The California DOC called out 10% ballistic gelatin and the current standard for NIJ and HOSDB calls out a multi-part foam and rubber backing material.
  • Using Roma clay backing, only metallic stab solutions met the 109 joule Calif. DOC ice pick requirement
  • Using 10% Gelatin backing, all fabric stab solutions were able to meet the 109 joule Calif. DOC ice pick requirement.
  • Most recently the Draft ISO prEN ISO 14876 norm selected Roma as the backing for both ballistics and stab testing.


This history helps explain an important factor in Ballistics and Stab armor testing, backing stiffness affects armor penetration resistance. The energy dissipation of the armor-tissue system is Energy = Force x Displacement when testing on backings that are softer and more deformable the total impact energy is absorbed at lower force. When the force is reduced by a softer more compliant backing the armor is less likely to be penetrated. The use of harder Roma materials in the ISO draft norm makes this the most rigorous of the stab standards in use today.

Rifle resistant armor

Because of the limitations of the technology a distinction is made between handgun protection and rifle protection. See NIJ levels 3 and 4 for typical requirements for rifle resistant armor. Broadly rifle resistant armor is of two basic types: ceramic plate
Ceramic plate
Ceramic plates are commonly used as inserts in soft ballistic vests. Most ceramic plates used in body armor provide National Institute of Justice Type III protection, allowing them to stop rifle bullets. Ceramic plates are a form of composite armor...

-based systems and hard fiber-based laminate systems. Many rifle armor components contain both hard ceramic components and laminated textile materials used together. Various ceramic materials types are in use, however: Aluminum Oxide, Boron Carbide and Silicon Carbide are the most common. The fibers used in these systems are the same as found in soft textile armor. However, for rifle protection high pressure lamination of ultra high molecular weight Polyethylene with a Kraton matrix is the most common.

The Small Arms Protective Insert (SAPI) and the enhanced SAPI plate for the US DOD generally has this form. Because of the use of ceramic plates for rifle protection, these vests are 5–8 times as heavy on an area basis as handgun protection. The weight and stiffness of rifle armor is a major technical challenge. The density, hardness and impact toughness are among the materials properties that are balanced to design these systems. While ceramic materials have some outstanding properties for ballistics they have poor fracture toughness. Failure of ceramic plates by cracking must also be controlled. For this reason many ceramic rifle plates are a composite. The strike face is ceramic with the backface formed of laminated fiber and resin materials. The hardness of the ceramic prevents the penetration of the bullet while the tensile strength of the fiber backing helps prevent tensile failure. Examples of rifle resistant outer vests include the Interceptor body armor
Interceptor body armor
Interceptor Body Armor is the United States Army's primary bulletproof vest. The Interceptor design replaced the older fragmentation protective Personnel Armor System for Ground Troops body armor system, introduced in the early 1980s...

 and the Improved Outer Tactical Vest
Improved Outer Tactical Vest
The Improved Outer Tactical Vest, or IOTV, is an enhanced version of, and a replacement for, the older Outer Tactical Vest variant of the Interceptor body armor, as fielded by the United States Army...

.

Armor Piercing Ammunition Core Hardness and Protection

The standards for armor-piercing rifle bullet
Bullet
A bullet is a projectile propelled by a firearm, sling, or air gun. Bullets do not normally contain explosives, but damage the intended target by impact and penetration...

s aren't clear-cut, because the penetration of a bullet depends on the hardness of the target armor. However there are a few general rules. For example, bullets with a soft lead-core and copper jacket are too easily deformed to penetrate hard materials, whereas rifle bullets manufactured with very hard core materials, like tungsten carbide, are designed for maximum penetration into hard armor. Most other core materials would have effects between lead and tungsten carbide. Many common bullets, such as the 7.62x39mm M43 standard cartridge for the AK47 rifle, have a steel core with hardness rating ranging from Rc35 mild steel up to Rc45 medium hard steel.

Additionally, as the hardness of the bullet core increases, so must the amount of ceramic plating used to stop penetration. Like in soft ballistics, a minimum ceramic material hardness of the bullet core is required to damage their respective hard core materials, however in armor-piercing rounds the bullet core is eroded rather than deformed.

The US Department of Defense uses two classes of protection from armor-piercing rifle bullets. The first, the Small Arms Protective Insert (SAPI), called for ceramic composite plates with a mass of 20–30 kg/m2 (4–5 lb/ft2). Later, the Enhanced SAPI (ESAPI) specification was developed to protect from more penetrative ammunition. ESAPI ceramic plates have a density of 35–45 kg/m2 (7–9 lb/ft2), and are designed to stop bullets like the 7.62 x 63 AP(M2) with an engineered hard core.

Cercom, now BAE systems, CoorsTek
CoorsTek
CoorsTek, Inc. is a privately owned manufacturer of technical ceramics, semiconductor tooling, plastic tubing, medical devices and other industrial products. CoorsTek’s headquarters and primary factories are located in Golden, Colorado, USA, near the foothills west of Denver. The company is...

, Ceradyne, Tencate, Honeywell, DSM, Pinnacle Armor and a number of other engineering companies develop and manufacture the materials for composite ceramic rifle armor.

Explosive protection

Bomb disposal
Bomb disposal
Bomb disposal is the process by which hazardous explosive devices are rendered safe. Bomb disposal is an all encompassing term to describe the separate, but interrelated functions in the following fields:*Military:...

 officers often wear heavy armor designed to protect against most effects of a moderate sized explosion, such as bombs encountered in terror threats. Full head helmet, covering the face and some degree of protection for limbs is mandatory in addition to very strong armor for the torso. An insert to protect the spine is usually applied to the back, in case an explosion blasts the wearer. Visibility and mobility of the wearer is severely limited, as is the time that can be spent working on the device. Armor designed primarily to counter explosives is often somewhat less effective against bullets than armor designed for that purpose. The sheer mass of most bomb disposal armor usually provides some protection, and bullet-specific trauma plates are compatible with some bomb disposal suits. Bomb disposal technicians try to accomplish their task if possible using remote methods (e.g., robots). Actually laying hands on a bomb is only done in an extremely life-threatening situation, where the hazards to people and critical structures cannot be lessened by using wheeled robots or other techniques.

Early “Ice Pick” test

In the mid-1980s the state of California Department of Corrections
California Department of Corrections and Rehabilitation
The California Department of Corrections and Rehabilitation is responsible for the operation of the California state prison and parole systems. CDC&R is the second largest law enforcement or police agency in the United States behind the New York City Police Department which employs approximately...

 issued a requirement for a body armor using a commercial ice pick as the test penetrator. The test method attempted to simulate the capacity of a human attacker to deliver impact energy with their upper body. As was later shown by the work of the former British PSDB, this test over stated the capacity of human attackers. The test used a drop mass or sabot that carried the ice pick. Using gravitational force, the height of the drop mass above the vest was proportional to the impact energy. This test specified 109 joules (81 ft·lbf) of energy and a 7.3 kg (16 lb) drop mass with a drop height of 153 cm (60 in).

The ice pick has a 4 mm (0.16 in) diameter with a sharp tip with a 5.4 m/s (17 ft/s) terminal velocity in the test. The California standard did not include knife or cutting edge weapons in the test protocol. The test method used the oil/clay (Roma Plastilena) tissue simulant as a test backing. In this early phase only titanium and steel plate offerings were successful in addressing this requirement. Point Blank developed the first ice pick certified offerings for CA Department of Corrections in shaped titanium sheet metal. Vests of this type are still in service in US corrections facilities as of 2008.

Beginning in the early 1990s, an optional test method was approved by California which permitted the use of 10% ballistic gelatin as a replacement for Roma clay. The transition from hard, dense clay-based Roma to soft low-density gelatin allowed all textile solutions to meet this attack energy requirement. Soft all textile “ice pick” vests began to be adopted by California and other US states as a result of this migration in the test methods. It is important for users to understand that the smooth, round tip of the ice pick does not cut fiber on impact and this permits the use of textile based vests for this application.

The earliest of these “all” fabric vests designed to address this ice pick test was Warwick Mills’s TurtleSkin ultra tightly woven para-aramid fabric with a patent filed in 1993. Shortly after the TurtleSkin work, in 1995 DuPont patented a medium density fabric that was designated as Kevlar Correctional. It should be noted that these textile materials do not have equal performance with cutting-edge threats and these certifications were only with ice pick and were not tested with knives.

Knife standards developed by HOSDB-Stab and Slash

Parallel to the US development of “ice pick” vests the British police, PSDB, was working on standards for knife resistant body armor. Their program adopted a rigorous scientific approach and collected data on human attack capacity. Their ergonomic study suggested three levels of threat: 25, 35 and 45 joules of impact energy. In addition to impact energy attack, velocities were measured and were found to be 10–20 m/s (much faster than the California test). Two commercial knives were selected for use in this PSDB test method. In order to test at a representative velocity, an air cannon method was developed to propel the knife and sabot at the vest target using compressed air. In this first version, the PSDB ’93 test also used oil/clay materials as the tissue simulant backing. The introduction of knives which cut fiber and a hard-dense test backing required stab vest manufactures to use metallic components in their vest designs to address this more rigorous standard. The current standard HOSDB Body Armour Standards for UK Police (2007) Part 3: Knife and Spike Resistance is harmonized with the US NIJ OO15 standard Use a drop test method and use a composite foam backing at a tissue simulant. Both the HOSDB and the NIJ test now specify engineered blades, double edged S1 and single edge P1 as well as the spike.

In addition to the stab standards HOSDB has developed a standard for Slash Resistance (2006). This standard like the stab standards is based on drop testing with a test knife in a mounting of controlled mass. The Slash test uses the Stanley Utility knife or box cutter blades. The Slash standard tests cut resistance of the armor panel parallel to the direction of blade travel. The test equipment measures the force at the instant the blade tip produces a sustained slash through the vest. The criteria requires that slash failure of the armor be greater than 80 newtons of force.

Combination stab and ballistic vests

Vests that combined stab and ballistic protection were a significant innovation in the 1990s period of vest development. The starting point for this development were the ballistic-only offerings of that time using NIJ Level 2A, 2, and 3A or HOSDB HG 1 and 2, with compliant ballistic vest products being manufactured with areal densities of between 5.5 and 6 kg/m² (1.1 and 1.2 lb/ft² or 18 and 20 oz/ft²). However police forces were evaluating their “street threats” and requiring vests with both knife and ballistic protection. This multi-threat approach is common in the United Kingdom and other European countries and is less popular in the USA. Unfortunately for multi-threat users, the metallic array and chainmail
Mail (armour)
Mail is a type of armour consisting of small metal rings linked together in a pattern to form a mesh.-History:Mail was a highly successful type of armour and was used by nearly every metalworking culture....

 systems that were necessary to defeat the test blades offered little ballistic performance. The multi-threat vests have areal densities are close to the sum of the two solutions separately. These vests have mass values in the 7.5–8.5 kg/m² (1.55–1.75 lb/ft²) range. Ref (NIJ and HOSDB certification listings). Rolls Royce Composites -Megit and Highmark produced metallic array systems to address this HOSDB standard. These designs were used extensively by the London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...

 Metropolitan Police Service
Metropolitan Police Service
The Metropolitan Police Service is the territorial police force responsible for Greater London, excluding the "square mile" of the City of London which is the responsibility of the City of London Police...

 and other agencies in the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

.

Standards update US and UK

As vest manufactures and the specifying authorities worked with these standards, the UK and US Standards teams began a collaboration on test methods. A number of issues with the first versions of the tests needed to be addressed. The use of commercial knives with inconsistent sharpness and tip shape created problems with test consistency. As a result, two new “engineered blades” were designed that could be manufactured to have reproducible penetrating behavior. The tissue simulants, Roma clay and gelatin, were either unrepresentative of tissue or not practical for the test operators. A composite-foam and hard-rubber test backing was developed as an alternative to address these issues. The drop test method was selected as the baseline for the updated standard over the air cannon option. The drop mass was reduced from the “ice pick test” and a wrist-like soft linkage was engineered into the penetrator-sabot to create a more realistic test impact. These closely related standards were first issued in 2003 as HOSDB 2003 and NIJ 0015. (The Police Scientific Development Branch (PSDB) was renamed the Home Office Scientific Development Branch in 2004.

Stab and spike vests

These new standards created a focus on Level 1 at 25 joule, Level 2 at 35 joule, Level 3 at 45 joule protection as tested with the new engineered knives defined in these test documents. The lowest level of this requirement at 25 joules was addressed by a series of textile products of both wovens, coated wovens and laminated woven materials. All of these materials were based on Para-aramid
Aramid
Aramid fibers are a class of heat-resistant and strong synthetic fibers. They are used in aerospace and military applications, for ballistic rated body armor fabric and ballistic composites, in bicycle tires, and as an asbestos substitute. The name is a portmanteau of "aromatic polyamide"...

 fiber. The co-efficient of friction for ultra high molecular weigh polyethylene (UHMWPE) prevented its use in this application. The TurtleSkin DiamondCoat and Twaron SRM products addressed this requirement using a combination of Para-Aramid wovens and bonded ceramic grain. These ceramic-coated products do not retain the flexibility and softness of un-coated textile materials.

For the higher levels of protection L2 and L3, the very aggressive penetration of the small, thin P1 blade has resulted in the continued use of metallic components in stab armor. In Germany, Mehler Vario Systems have developed sophisticated hybrid vests of woven para-aramid and chain mail their solution was selected the London Metro Police. Another German company BSST, in cooperation with Warwick Mills, has developed a system to meet the ballistic-stab requirement using Dyneema laminate and an advanced metallic-array system, TurtleSkin MFA. This system is currently implemented in Holland. The trend in multi threat armor continues with requirements for needle protection in the Draft ISO prEN ISO 14876 norm. In many countries there is also an interest to combine military style explosive fragmentation protection with bullet-ballistics and stab requirements.

It is common knowledge that an arrow
Arrow
An arrow is a shafted projectile that is shot with a bow. It predates recorded history and is common to most cultures.An arrow usually consists of a shaft with an arrowhead attached to the front end, with fletchings and a nock at the other.- History:...

 broadhead, such as those used for hunting, will pierce all known fabric vests designed to stop the blunt impacts of bullets. The broadhead is significantly if not completely hindered by ceramic or steel trauma plates, but without these, a broadhead-tipped arrow released from a bow with a draw weight of 70 pounds will penetrate four rifle-proof vests.

Vest sizing, carriers and encapsulation

In order for ballistic protection to be wearable the ballistic panels and hard rifle-resistant plates are fitted inside a special carrier. The carrier is the visible part of a ballistic vest. The most basic carrier includes pockets which hold the ballistic panels and straps for mounting the carrier on the user. There are two major types of carriers: military or tactical carriers that are worn over the shirt, and covert law enforcement type carriers that are worn under the shirt.

Military carriers

The military type of carrier, English police waistcoat carrier, or police tactical carrier most typically has a series of webbing, hook and loop, and snap type connectors on the front and back face. This permits the wearer to mount various gear to the carrier in many different configurations. This load carriage feature is an important part of uniform and operational design for police weapons teams and the military.
In addition to load carriage, this type of carrier may include pockets for neck protection, side plates, groin plates, and backside protection. Because this style of carrier is not close fitting, sizing in this system is straightforward for both men and women, making custom fabrication unnecessary.

Concealable carriers

Law enforcement carriers in some countries are concealable. The carrier holds the ballistic panels close to the wearers body and a uniform shirt is worn over the carrier. This type of carrier must be designed to conform closely to the officer's body shape. For concealable armor to conform to the body it must be correctly fitted to a particular individual. Many programs specify full custom measurement and manufacturing of armor panels and carriers to ensure good fit and comfort for concealable armor. Officers who are either female or obese have more difficulty in getting accurately measured and having comfortable armor fabricated.

Vest slips

A third textile layer is often found between the carrier and the ballistic components. The ballistic panels are covered in a coated pouch or slip. This slip provides the encapsulation of the ballistic materials. Slips are manufactured in two types: heat sealed hermetic slips and simple sewn slips. For some ballistic fibers such as Kevlar
Kevlar
Kevlar is the registered trademark for a para-aramid synthetic fiber, related to other aramids such as Nomex and Technora. Developed at DuPont in 1965, this high strength material was first commercially used in the early 1970s as a replacement for steel in racing tires...

 the slip is a critical part of the system. The slip prevents moisture from the user's body from saturating the ballistic materials. This protection from moisture cycling increases the useful life of the armor.

Progress in fibre science

In recent years, advances in material science have opened the door to the idea of a literal "bulletproof vest" able to stop handgun and rifle bullets with a soft textile vest, without the assistance of additional metal or ceramic plating. However, progress is moving at a slower rate compared to other technical disciplines. The most recent offering from Kevlar, Protera, was released in 1996. Current soft body armor can stop most handgun rounds (which has been the case for roughly 15 years ), but armor plates are needed to stop rifle rounds and steel core handgun rounds such as 7.62x25. The para-aramids have not progressed beyond the limit of 23 grams per denier in fiber tenacity.

Modest ballistic performance improvements have been made by new producers of this fiber type. Much the same can be said for the UHMWPE material; the basic fiber properties have only advanced to the 30–35 g/d range. Improvements in this material have been seen in the development of cross-plied non-woven laminate, e.g. Spectra Shield. The major ballistic performance advance of fiber PBO
Zylon
Zylon is a trademarked name for a range of thermoset liquid crystalline polyoxazole...

 is known as a "cautionary tale" in materials science. This fiber permitted the design of handgun soft armor that was 30–50% lower in mass as compared to the aramid and UHMWPE materials. However this higher tenacity was delivered with a well-publicized weakness in environmental durability.

Akzo-Magellan (now DuPont) teams have been working on fiber called M5 fiber
M5 fiber
M5 fiber is a high-strength synthetic fiber first developed by Dr. Doetze Sikkema and his team at the Dutch chemical firm Akzo Nobel...

; however, its announced startup of its pilot plant has been delayed more than 2 years. Data suggests if the M5 material can be brought to market, its performance will be roughly equivalent to PBO. In May 2008, the Teijin Aramid group announced a “super-fibers” development program. The Teijin emphasis appears to be on computational chemistry to define a solution to high tenacity without environmental weakness.

The materials science of second generation “super” fibers is complex, requires large investments, and represent significant technical challenges. Research aims to develop artificial spider silk which could be super strong, yet light and flexible. Other research has been done to harness nanotechnology to help create super-strong fibers that could be used in future bulletproof vests.

Textile wovens and laminates research

Finer yarns and lighter woven fabrics have been a key factor in improved ballistic results. The cost of ballistic fiber goes up dramatically as yarn size goes down, so it is unclear how long this trend can continue. The current practical limit of fiber size is 200 denier with most wovens limited at the 400 denier level. Three-dimensional weaving with fibers connecting flat wovens together into a 3D system are being considered for both hard and soft ballistics. Team Engineering Inc is designing and weaving these multi layer materials. Dyneema DSM has developed higher performance laminates using a new, higher strength fiber designated SB61, and HB51. DSM feels this advanced material provides some improved performance, however the SB61 “soft ballistic” version has been recalled. At the Shot Show in 2008, a unique composite of interlocking steel plates and soft UHWMPE plate was exhibited by TurtleSkin. In combination with more traditional woven fabrics and laminates a number of research efforts are working with ballistic felts. Tex Tech has been working on these materials. Like the 3D weaving, Tex Tech sees the advantage in the 3-axis fiber orientation.

Developments in ceramic armor

Ceramic materials, materials processing and progress in ceramic penetration mechanics are significant areas of academic and industrial activity. This combined field of ceramics armor research is broad and is perhaps summarized best by The American Ceramics Society. ACerS has run an annual armor conference for a number of years and compiled a proceedings 2004–2007. An area of special activity pertaining to vests is the emerging use of small ceramic components. Large torso sized ceramic plates are complex to manufacture and are subject to cracking in use. Monolithic plates also have limited multi hit capacity as a result of their large impact fracture zone These are the motivations for new types of armor plate. These new designs use 2 and 3 dimensional arrays of ceramic elements that can be rigid, flexible or semi-flexible. Dragon Skin body armor
Dragon Skin (body armor)
Dragon Skin is a type of ballistic vest made by Pinnacle Armor. It is currently produced in Fresno, California. Its characteristic two-inch-wide circular discs overlap like scale armor, creating a flexible vest that allows a good range of motion and can allegedly absorb a high number of hits...

 is one these systems. European developments in spherical and hexagonal arrays have resulted in products that have some flex and multi hit performance. The manufacture of array type systems with flex, consistent ballistic performance at edges of ceramic elements is an active area of research. In addition advanced ceramic processing techniques arrays require adhesive assembly methods. One novel approach is use of hook and loop fasteners to assemble the ceramic arrays.

Nanomaterials in ballistics

Currently, there are a number of methods by which nanomaterials are being implemented into body armor production. The first, developed at University of Delaware
University of Delaware
The university is organized into seven colleges:* College of Agriculture and Natural Resources* College of Arts and Sciences* Alfred Lerner College of Business and Economics* College of Earth, Ocean and Environment* College of Education and Human Development...

 is based on nanoparticles within the suit that become rigid enough to protect the wearer as soon as a kinetic energy threshold is surpassed. These coatings have been described as shear thickening
Dilatant
A dilatant material is one in which viscosity increases with the rate of shear strain. Such a shear thickening fluid, also known by the acronym STF, is an example of a non-Newtonian fluid....

 fluids. These nano-infused fabrics have been licensed by BAE systems, but as of mid 2008, no products have been released based on this technology.

In 2005 an Israeli company, ApNano
ApNano
ApNano Materials is a US company with a research facility in Ness Ziona, Israel that designs and manufactures nanotechnology-based products....

, developed a material that was always rigid. It was announced that this nanocomposite
Nanocomposite
A nanocomposite is as a multiphase solid material where one of the phases has one, two or three dimensions of less than 100 nanometers , or structures having nano-scale repeat distances between the different phases that make up the material...

 based on tungsten disulfide
Tungsten(IV) sulfide
Tungsten sulfide is the chemical compound with the formula WS2. It occurs naturally as the rare mineral called tungstenite. This material is a component of certain catalysts used for hydrodesulfurization and hydrodenitrification....

 nanotube
Inorganic nanotube
An inorganic nanotube is a cylindrical molecule often composed of metal oxides, and morphologically similar to a carbon nanotube. Inorganic nanotubes have been observed to occur naturally in some mineral deposits....

s was able to withstand shocks generated by a steel projectile traveling at velocities of up to 1.5 km/s. The material was also reportedly able to withstand shock pressures generated by the impacts of up to 250 metric tons-force per square centimeter (24.5 gigapascal
Pascal (unit)
The pascal is the SI derived unit of pressure, internal pressure, stress, Young's modulus and tensile strength, named after the French mathematician, physicist, inventor, writer, and philosopher Blaise Pascal. It is a measure of force per unit area, defined as one newton per square metre...

s; 3,550,000 psi). During the tests, the material proved to be so strong that after the impact the samples remained essentially unmarred. Additionally, a recent study in France tested the material under isostatic
Isostasy
Isostasy is a term used in geology to refer to the state of gravitational equilibrium between the earth's lithosphere and asthenosphere such that the tectonic plates "float" at an elevation which depends on their thickness and density. This concept is invoked to explain how different topographic...

 pressure and found it to be stable up to at least 350 tf/cm² (34 GPa; 5,000,000 psi).

As of mid-2008, spider silk bulletproof vests and nano-based armors are being developed for potential market release . Both the British and American militaries have expressed interest in a carbon fiber woven from carbon nanotube
Carbon nanotube
Carbon nanotubes are allotropes of carbon with a cylindrical nanostructure. Nanotubes have been constructed with length-to-diameter ratio of up to 132,000,000:1, significantly larger than for any other material...

s that was developed at University of Cambridge
University of Cambridge
The University of Cambridge is a public research university located in Cambridge, United Kingdom. It is the second-oldest university in both the United Kingdom and the English-speaking world , and the seventh-oldest globally...

 and has the potential to be used as body armor. In 2008, large format carbon nanotube sheets began being produced at Nanocomp.

Australia

In Australia, it is illegal to import body armour without prior authorization from Australian Customs and Border Protection Service. It is also illegal to
possess body armour without authorisation in South Australia
South Australia
South Australia is a state of Australia in the southern central part of the country. It covers some of the most arid parts of the continent; with a total land area of , it is the fourth largest of Australia's six states and two territories.South Australia shares borders with all of the mainland...

, Victoria
Victoria (Australia)
Victoria is the second most populous state in Australia. Geographically the smallest mainland state, Victoria is bordered by New South Wales, South Australia, and Tasmania on Boundary Islet to the north, west and south respectively....

, Northern Territory
Northern Territory
The Northern Territory is a federal territory of Australia, occupying much of the centre of the mainland continent, as well as the central northern regions...

, ACT
Australian Capital Territory
The Australian Capital Territory, often abbreviated ACT, is the capital territory of the Commonwealth of Australia and is the smallest self-governing internal territory...

, Queensland
Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...

  & New South Wales
New South Wales
New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...

. In 2009 Tasmania
Tasmania
Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...

 considered passing control legislation as well.

Canada

In all Canadian provinces
Provinces and territories of Canada
The provinces and territories of Canada combine to make up the world's second-largest country by area. There are ten provinces and three territories...

 except for British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...

, it is legal to wear and to purchase body armor such as ballistic vests. Under British Columbia's Body Armour Control Act, it is illegal to possess body armour without a licence issued by the provincial government as of July 1, 2010. However, a 6 months grace period is provided for people to dispose or transfer the body armour to a licenced or exempted individual. Similar legislation has been passed in Alberta
Alberta
Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...

 but is not in force. Further, Bill C-349 in the House of Commons, proposes to create a separate offence for wearing body armor during or attempting the commission of an indictable offence
Indictable offence
In many common law jurisdictions , an indictable offence is an offence which can only be tried on an indictment after a preliminary hearing to determine whether there is a prima facie case to answer or by a grand jury...

.

The Netherlands

The civilian ownership of body armour is unregulated in the Netherlands
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...

 and body armour in various ballistic grades is sold by a range of different vendors, mainly aimed at providing to security guards and VIP's. The use of body armour while committing a crime is not an additional offense in itself, but may be interpreted as so under different laws such as resisting arrest.

United States of America

United States law restricts possession of body armor for convicted violent felons. Many U.S. states also have penalties for possession or use of body armor by felons. In other states, such as Kentucky
Kentucky
The Commonwealth of Kentucky is a state located in the East Central United States of America. As classified by the United States Census Bureau, Kentucky is a Southern state, more specifically in the East South Central region. Kentucky is one of four U.S. states constituted as a commonwealth...

, possession is not prohibited, but probation or parole is denied to a person convicted of committing certain violent crimes while wearing body armor and carrying a deadly weapon. Additionally, some states outlaw the wearing of body armor while committing certain, usually violent, crimes.

Italy

In Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...

, the purchase, ownership and wear of ballistic vests and body armor is not subject to any restriction, except for those ballistic protections that are developed under strict military specifications and/or for main military usage, thus considered by the law as "armament materials" and forbidden to civilians. Furthermore, a number of laws and court rulings during the years have rehearsed the concept of a ballistic vest being mandatory to wear for those individuals who work in the private security
Security guard
A security guard is a person who is paid to protect property, assets, or people. Security guards are usually privately and formally employed personnel...

 sector.

European Union

In European Union
European Union
The European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...

 port and sale of ballistic vests and body armor are allowed in Europe, except protections that are developed under strict military specifications and/or for main military usage, shield above the level of protection NIJ 4, thus considered by the law as "armament materials" and forbidden to civilians. There are many shops in Europe that sell ballistic vests and body armor used or new.

See also

  • Brigandine
    Brigandine
    A brigandine is a form of body armour from the Middle Ages. It is a cloth garment, generally canvas or leather, lined with small oblong steel plates riveted to the fabric....

     (an earlier form of vest, used to defend against swords, knives, etc.)
  • Buff coat
    Buff coat
    The European Buff coat was an item of leather clothing worn by both the infantry and cavalry during the 17th century, usually worn under armour...

     (an early form of ballistic vest, suitable for use only against pistol balls, but not musket balls)
  • Flak jacket
    Flak jacket
    thumb|300px|The two components of an obsolete British military flak vest. On the left, the nylon vest. On the right, the several layers of [[ballistic nylon]] that provide the actual protection...

  • Hauberk
    Hauberk
    A hauberk is a shirt of chainmail. The term is usually used to describe a shirt reaching at least to mid-thigh and including sleeves. Haubergeon generally refers to a shorter variant with partial sleeves, but the terms are often used interchangeably.- History :The word hauberk is derived from the...

     (an earlier form of body armor, used to defend against swords, knives, etc.)
  • Mail (armour)
    Mail (armour)
    Mail is a type of armour consisting of small metal rings linked together in a pattern to form a mesh.-History:Mail was a highly successful type of armour and was used by nearly every metalworking culture....

  • Terminal ballistics
    Terminal ballistics
    Terminal ballistics, a sub-field of ballistics, is the study of the behavior of a projectile when it hits its target. It is often referred to as stopping power when dealing with human or other living targets. Terminal ballistics is relevant both for small caliber projectiles as well as for large...


External links

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