Body armor/armour, personal armor/armour, suits of armour or coats of armour all refer to protective clothing, designed to absorb and/or deflect slashing, bludgeoning and penetrating attacks by weapons. It was historically used to protect military personnel, whereas today, it is also used to protect various types of police (riot police in particular), , private or . Today there are two main types: regular non-plated personal armor (used by the people mentioned above, except combat soldiers) and hard-plate reinforced personal armor, which is used by combat soldiers, police tactical units, private citizens, and hostage rescue teams.
Chinese armour has a long history, beginning in Ancient China. In East Asian history laminated armor such as lamellar armour, and styles similar to the coat of plates, and brigandine were commonly used. Later cuirasses and plates were also used. In pre-Qin dynasty times, leather armor was made out of rhinoceros. Chinese influence in Japan would result in the Japanese adopting Chinese styles, their Samurai being a result of this influence.
Early plate in Italy, and elsewhere in the 13th to 15th centuries were made of iron. Iron armor could be Carburizing or Case hardening to give a surface of harder steel. Plate armor became cheaper than mail by the 15th century as it required much less labor and labor had become much more expensive after the Black Death, though it did require larger furnaces to produce larger blooms. Mail continued to be used to protect those joints which could not be adequately protected by plate, such as the armpit, crook of the elbow and groin. Another advantage of plate was that a lance rest could be fitted to the breast plate. The small skull cap evolved into a bigger true helmet, the bascinet, as it was lengthened downward to protect the back of the neck and the sides of the head. Additionally, several new forms of fully enclosed helmets were introduced in the late 14th century to replace the great helm, such as the sallet and barbute and later the armet and close helm.
Probably the most recognized style of armor in the world became the plate armour associated with the of the European Late Middle Ages, but continuing to the early 17th-century Age of Enlightenment in all European countries.
By about 1400 the full harness of plate armor had been developed in armories of Lombardy Heavy cavalry dominated the battlefield for centuries in part because of their armor.
In the early 15th century, small "hand cannon" first began to be used, in the Hussite Wars, in combination with Wagenburg tactics, allowing infantry to defeat armored knights on the battlefield. At the same time were made more powerful to pierce armor, and the development of the Swiss Pike square formation also created substantial problems for heavy cavalry. Rather than dooming the use of body armor, the threat of small firearms intensified the use and further refinement of plate armor. There was a 150-year period in which better and more metallurgically advanced steel armor was being used, precisely because of the danger posed by the gun. Hence, guns and cavalry in plate armor were "threat and remedy" together on the battlefield for almost 400 years. By the 15th century Italian armor plates were almost always made of steel. In Southern Germany armorers began to harden their steel armor only in the late 15th century. They would continue to harden their steel for the next century because they and tempered their product which allowed for the fire-gilding to be combined with tempering.
The quality of the metal used in armor deteriorated as armies became bigger and armor was made thicker, necessitating breeding of larger cavalry horses. If during the 14th and 15th centuries armor seldom weighed more than 15 kg, then by the late 16th century it weighed 25 kg. The increasing weight and thickness of late 16th-century armor therefore gave substantial resistance.
In the early years of pistol and arquebuses, firearms were relatively low in velocity. The full suits of armor, or breast plates actually stopped bullets fired from a modest distance. The front breast plates were, in fact, commonly shot as a test. The impact point would often be encircled with engraving to point it out. This was called the "proof". Armor often also bore an insignia of the maker, especially if it was of good quality. Crossbow bolts, if still used, would seldom penetrate good plate, nor would any bullet unless fired from close range.
In effect, rather than making plate armor obsolete, the use of firearms stimulated the development of plate armor into its later stages. For most of that period, it allowed horsemen to fight while being the targets of defending arquebuseers without being easily killed. Full suits of armor were actually worn by generals and princely commanders right up to the 1710s.
At the start of World War I in 1914, thousands of the French rode out to engage the German Cavalry who likewise used helmets and armor. By that period, the shiny armor plate was covered in dark paint and a canvas wrap covered their elaborate Napoleonic-style helmets. Their armor was meant to protect only against sabre and light . The cavalry had to beware of high velocity and like the foot soldiers, who at least had a trench to protect them.
On the other hand, Twaron is similar to Kevlar. They both belong to the aramid family of synthetic fibers. The only difference is that Twaron was first developed by Akzo in the 1970s. Twaron was first commercially produced in 1986. Now, Twaron is being manufactured by Teijin Aramid. Like Kevlar, Twaron is a strong, synthetic fiber. It is also heat resistant. It has many applications. It can be used in the production of several materials which include the military, construction, automotive, aerospace, and even sports. Among the examples of Twaron-made materials are body armor, helmets, ballistic vests, speaker woofers, drumheads, tires, turbo hoses, wire ropes, and cables.
Another fiber used to manufacture a bullet-resistant vest is Dyneema. Originated in the Netherlands, Dyneema has an extremely high strength-to-weight ratio (a 1-mm-diameter rope of Dyneema can bear up to a 240-kg load), is light enough that it can float on water, and has high energy absorption characteristics. Dyneema is a polyethylene fiber. Since the introduction of the Dyneema Force Multiplier Technology in 2013, many body armor manufacturers have switched to Dyneema for their high-end armor solutions.
A ballistic face mask is designed to protect the wearer from ballistic threats. Ballistic face masks are usually made of kevlar or other bullet-resistant materials and the inside of the mask may be padded for shock absorption, depending on the design. Due to weight restrictions, protection levels range only up to NIJ Level IIIA.
Metal or ceramic plates can be used with a soft vest, providing additional protection from rifle rounds, and metallic components or tightly-woven fiber layers can give soft armor resistance to stab and slash attacks from a knife. Soft vests are commonly worn by police forces, private citizens and private or , whereas hard-plate reinforced vests are mainly worn by combat soldiers, police tactical units and hostage rescue teams.
A modern equivalent may combine a ballistic vest with other items of protective clothing, such as a combat helmet. Vests intended for police and military use may also include ballistic shoulder and side protection armor components, and explosive ordnance disposal technicians wear heavy armor and helmets with face visors and spine protection.
Standards are regional. Around the world ammunition varies and as a result the armor testing must reflect the threats found locally. According to statistics from the US National Law Enforcement Officers Memorial Fund, "a law enforcement officer’s job is extremely dangerous, with one officer being killed every 53 hours in the line of duty in. Even more astounding is that this number is on the rise. In 2011, 173 officers were killed, with 68 of them being killed due to a gun-related incident."
While many standards exist, a few standards are widely used as models. The US National Institute of Justice ballistic and stab documents are examples of broadly-accepted standards. Since the time that NIJ started testing, the lives of more than 3,000 officers were saved. In addition to the NIJ, the United Kingdom's Home Office Scientific Development Branch (HOSDB—formerly the Police Scientific Development Branch (PSDB)) standards are also used by a number of other countries and organizations. These "model" standards are usually adapted by other countries by following the same basic test methodologies, while changing the specific ammunition tested. NIJ Standard-0101.06 has specific performance standardization for bullet resistant vests used by law enforcement. This rates vests on the following scale against penetration and also blunt trauma protection (deformation):
In the beginning of 2018, NIJ is expected to introduce the new NIJ Standard-0101.07. This new standard will completely replace the NIJ Standard-0101.06. The current system of using Roman numerals (II, IIIA, III, and IV) to indicate the level of threat will disappear and be replaced by a naming convention similar to the standard developed by UK Home Office Scientific Development Branch. HG (Hand Gun) is for soft armor and RF (Rifle) is for hard armor. Another important change is that the test-round velocity for conditioned armor will be the same as that for new armor during testing. For example, for NIJ Standard-0101.06 Level IIIA the .44 Magnum round is currently shot at 408 m/s for conditioned armor and at 436 m/s for new armor. For the NIJ Standard-0101.07, the velocity for both conditioned and new armor will be the same.
In January 2012, the NIJ introduced BA 9000, body armor quality management system requirements as a quality standard not unlike ISO 9001 (and much of the standards were based on ISO 9001).
(.22 LR; .380 ACP)
|This armor would protect against:
(9 mm; .40 S&W; .45 ACP)
|New armor protects against:
(9 mm; .357 Magnum)
|New armor protects against:
(.357 SIG; .44 Magnum)
|New armor protects against:
|Conditioned armor protects against:
(Armor Piercing Rifle)
|Conditioned armor protects against:
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 modelling 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 this 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.Kevlar, Twaron, Dyneema, Spectra technical data (As a result of this, the major test standards call for wet testing of textile armor.NIJ, HOSDB, US-Army and ISO ballistic test methods) 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."Third Status Report to the Attorney General on Safety Initiative Testing and Activities"
Variability reduces the predictive power of a determination of V0. If for example, the V0 of an armor design is measured to be 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 standardsARMY MIL-STD-662F V50 BALLISTIC TEST FOR ARMOR define a commonly used procedure for this test. The goal is to get three shots that penetrate and a second group of three shots that are stopped by the armor all within a specified velocity range. It is possible, and desirable to have a penetration velocity lower than a stop velocity. These three stops and three penetrations can then be used to calculate a V50 velocity.Army MIL-STD-662F V50 BALLISTIC TEST FOR ARMOR
In practice this measurement of V50 often 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.
The second part of "Casualty Reduction" strategy is a study of velocity distributions of fragments from munitions.Johnson, W., Collins, C., and Kindred, F., A Mathematical Model for Predicting Residual Velocities of Fragments After Perforating Helmets, Ballistic Research Laboratories Technical Note no. 1705, October 1968 Warhead explosives have blast speeds of to . As a result, they are capable of ejecting fragments at very high speeds of over 1000 m/s (3330 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 have a velocity of 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 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.