Bulletproof vest

A bulletproof vest is a specialized garment used by the military and law enforcement personnel. Bulletproof vests are designed to resist penetration by firearms. Most modern bulletproof vests are made of Kevlar fibers and/or ceramic plates. Despite its name, a "bulletproof" vest—or any other form of body armor—is never completely bulletproof. Most bulletproof vests can still be penetrated by high-caliber ammunition. Additionally, even if the vest stops a bullet, the individual wearing the armor may still be badly bruised or injured from the impact.

Brief History

Various forms of body armor have existed since before written history. Early armor was made from hides or bronze. Over time, body armor evolved into steel suits designed to stop swords, clubs, and arrows. Nobles and knights wore these expensive suits of armor to keep them safe from the vast majority of blows inflicted on the battlefield.

Early firearms drastically changed this dynamic. During the seventeenth century, firearms made battlefield armor obsolete. Early bullets often pierced thick, metal breastplates. Since nothing could stop a bullet, it was more effective for soldiers to forgo armor so they could be lighter and quicker.

By the end of the 1800s, researchers had developed the first bullet-resistant clothing. Made of dozens of layers of silk, the garment successfully stopped projectiles fired from the low-power, black powder firearms of the time. However, the garment was expensive and never became commercially popular. In addition, it earned a bad reputation when Archduke Franz Ferdinand, the leader of Austria, was assassinated while wearing one.

Most soldiers avoided wearing body armor until World War II and the invention of the flak jacket. The flak jacket was a thick, heavy vest made from dense ballistics nylon. Flak jackets were not designed to stop bullets and were ineffective against direct, small-arms fire. They were designed to deflect small amounts of shrapnel and debris from explosions. While flak jackets were hot and difficult to wear, they provided light protection to soldiers in the trenches.

In the late 1960s, the National Institute of Justice (NIJ) began researching other forms of body armor. They wanted to find a material that police officers could easily wear for a full day's work. The material would have to reliably stop small-arms fire and be light enough to wear for prolonged periods of time without seriously encumbering the officer. Over the next several years, researchers developed and studied Kevlar ballistic fabric.

Modern Body Armor

Kevlar was initially developed as a material to make super-tough tires. However, the NIJ soon realized its potential as a new form of body armor. Researchers designed three testing phases. In the first phases, researchers would determine whether Kevlar fabric could stop a lead bullet. In the second, they would determine how many layers of the material were necessary to protect officers from .22- and .38-caliber bullets. The third phase would involve medically testing the body armor.

The first and second rounds of testing for Kevlar vests were resounding successes. Just seven layers of the material could reliably stop small-caliber bullets from penetrating the vest. Kevlar is made of massive numbers of fibers that are woven incredibly tightly together. The fibers distribute the stress across a larger area, thereby stopping them from breaking, and most bullets are not thin enough to pass through the gaps between fibers. In many cases, the bullet will deform and begin to rotate upon striking the Kevlar, further distributing the force away from its target.

In the third phase of testing, researchers realized that stopping the bullet itself would not stop all of the kinetic energy released by the bullet's impact. Even when a bulletproof vest stops a bullet, the person wearing the bullet may still experience extreme bruising, organ damage, or even death. Thus, a layer of padding is sometimes included under the Kevlar. Researchers also realized that Kevlar quickly degrades when exposed to water or direct sunlight. For this reason, all Kevlar vests are worn inside a protective cloth covering. After all the testing was concluded, Kevlar vests were adopted by most police departments and militaries. Despite their drawbacks, bulletproof vests offer substantial amounts of protection against small-arms fire.

All modern body armor, including varieties of bulletproof vests, is not equal. The NIJ has devised a rating system to inform buyers of the degree of protection offered by any commercially available body armor. It includes five tiers of protection. Armor rated IIA is tested against 9mm and .40-caliber rounds. Armor rated II is tested against .357 rounds. Armor rated IIIA is tested against .44 Magnum rounds. Armor rated III is tested against 7.62mm NATO rounds. Armor type IV is tested against .30-caliber armor-piercing rounds. Each armor rating is guaranteed to stop at least one bullet of the specified capacity and provide the same level of protection against bullets tested at lower armor tiers. For example, an armor rated IV would stop at least one type of almost any bullet.

Higher tiers of armor commonly utilize rigid ballistics plating in addition to Kevlar. This plating, usually composed of ceramics or metals, is designed to provide an additional layer of protection over vital areas. However, these armors are prohibitively expensive and much more encumbering than standard Kevlar vests. For this reason, they are less commonly encountered among law enforcement officers and military personnel. Type I body armor, while considered acceptable before the NIJ standards were updated in 2008, is no longer tested. The NIJ has stated that criminals' increasing access to higher-powered firearms has made armor values lower than type IIA irrelevant to law enforcement.

Bibliography

"Body Armor History." GlobalSecurity.org, 2011, globalsecurity.org/military/systems/ground/body-armor2.htm. Accessed 18 Oct. 2016.

"Choosing the Right Body Armor." Safeguard Armor, safeguardarmor.com/articles/choosing-body-armor. Accessed 18 Oct. 2016.

Harris, Tom. "How Body Armor Works." HowStuffWorks.com, 1 May 2001, science.howstuffworks.com/body-armor.htm. Accessed 18 Oct. 2016.

Lammie, Rob. "A Brief History of Bulletproof Vests." Mental Floss, 23 Feb. 2010, mentalfloss.com/article/24039/brief-history-bulletproof-vests. Accessed 18 Oct. 2016.

"The New Body Armor Standard from NIJ: The FOP Perspective." Fraternal Order of Police, 2008, fop.net/CmsDocument/Doc/BodyArmorStandard.pdf. Accessed 18 Oct. 2016.

Romero, Frances. "A Brief History of Body Armor." Time, 7 Apr. 2009, content.time.com/time/business/article/0,8599,1889795,00.html. Accessed 18 Oct. 2016.

Swabie, Rachel. "A Brief History of Bulletproof." Gizmodo, 8 Mar. 2011, gizmodo.com/5778698/a-brief-history-of-bulletproof. Accessed 18 Oct. 2016.

"Who Invented the Bullet Proof Vest?" Tech-FAQ, tech-faq.com/who-invented-the-bullet-proof-vest.html. Accessed 18 Oct. 2016.