|The history of bullet proof vests:
Lightweight body armor or bulletproof vests have been widely available for use by law enforcement personnel for more than 20 years. Humans throughout recorded history have used various types of materials as body armor to protect themselves from injury in combat and other dangerous situations.
Initial bullet proof vests: At first, protective clothing and shields were made from animal skins. As civilizations became more advanced, wooden shields and then metal shields came into use. Eventually, metal was also used as body armor, what we now refer to as the suit of armor associated with the knights of the Middle Ages. However, with the advent of firearms (c.1500), most of the traditional body armor were no longer effective. In fact, the only real protection available against firearms were man-made barriers, such as stone or masonry walls, or natural barriers, such as rocks, trees, and ditches.
One of the first recorded instances of the use of primitive bulletproof vests or soft body armor was by the medieval Japanese, who used armor manufactured from silk. Although the first U.S. law enforcement officer to lose his life in the line of duty, U.S. Marshall Robert Forsyth, was shot and killed in 1794, it was not until the late 19th century that the first use of soft body armor in the United States was recorded.
At that time, the military explored the possibility of using soft body armor manufactured from silk. The project even attracted congressional attention after the assassination of President William McKinley in 1901. But while these bulletproof vests garments were shown to be effective against low-velocity bullets (traveling at 400 feet per second (ft/s) or less), they did not offer protection against the new generation of handgun ammunition being introduced at that time that traveled at velocities of more than 600 feet per second. This, along with the prohibitive cost of manufacturing the garment ($80 each, which amounts to approximately $1,400 in 1998 dollars) made the concept unacceptable. Armor of this type was said to have been worn by Archduke Francis Ferdinand of Austria when he was killed by a shot to the head, thereby precipitating World War I.
The U.S. Patent and Trademark Office lists records for bullet proof vests dating back to 1919 for various designs of bullet resistant and body armor type garments. One of the first documented instances where such a bullet proof vest was demonstrated for use by law enforcement officers is detailed in the April 2, 1931 edition of the Washington, D.C., Evening Star, where a bullet proof vest was demonstrated to members of the Metropolitan Police Department. However, none of these designs proved entirely effective or feasible for law enforcement or corrections use.
The next generation of anti ballistic bullet proof vest was introduced during World War II. The "flak jacket," constructed of ballistic nylon, provided protection primarily from munitions fragments and was ineffective against most pistol and rifle threats. These vests were also very cumbersome and bulky, and were restricted primarily to military use. It would not be until the late 1960s that new fibers were discovered that made today's modern generation of cancelable body armor possible.
The National Institute of Law Enforcement and Criminal Justice (NILECJ) -- predecessor of the National Institute of Justice (NIJ) -- initiated a research program to investigate development of a lightweight body armor or bullet proof vest that on-duty police could wear full time.
The investigation readily identified new materials that could be woven into a lightweight fabric with excellent ballistic resistant properties. Following initial laboratory research, the agency concluded that the objective of producing bulletproof vests or body armor suitable for full-time police use was achievable. In a parallel effort, the National Bureau of Standards' (now known as the National Institute of Standards and Technology) Law Enforcement Standards Laboratory (now known as the Office of Law Enforcement Standards - OLES) developed a performance standard that defined ballistic resistant requirements for police body armor. The National Bureau of Standards was a part of the NIJ Technology Assessment Program, which today is known as the National Law Enforcement and Corrections Technology Center (NLECTC).
Of all the equipment developed and evaluated in the 1970s by NIJ, one of its most significant achievements was the development of bullet proof vests that employed DuPont's Kevlar ballistic fabric. Ironically, the fabric was originally intended to replace steel belting in vehicle tires. Lester Shubin, who served as NIJ Technology Assessment Program Manager from 1971-1991, recalls:
"The Army notified me that DuPont had a new fabric to replace steel belting for high-speed tires. When I saw it, I realized it might be a great improvement over nylon for personal armor and bulletproof vests. Nicholas Montanarelli, then an Army Land Warfare technology specialist, and I took a piece of Kevlar to a gun range. We folded it over a couple of times and shot at it. The bullets didn't go through."
During the following 5 years, from 1971 to 1976, more than $3 million of NIJ funds were devoted to the development of body armor. The research and development program was a team effort involving several of the most innovative and technologically advanced private and government organizations in the country. Contractors from the private sector were The Aerospace Corporation and MITRE Corporation. The U.S. Army's contribution included the efforts of Edgewood Arsenal, Aberdeen Proving Grounds, and Natick Laboratories. The Lawrence Livermore Laboratory and the National Bureau of Standards were also involved in the program, as were the Federal Bureau of Investigation (FBI) and the Secret Service.
The development of body armor or bullet proof vests by NIJ was a four-phase effort that took place over several years. The first phase involved testing Kevlar fabric to determine whether it could stop a lead bullet. The second phase involved determining the number of layers of material necessary to prevent penetration by bullets of varying speeds and calibers and developing a prototype vest that would protect officers against the most common threats -- the .38 Special and the .22 Long Rifle bullets. Bullets from 9mm, .45, and .32 caliber weapons were also investigated.
By 1973, researchers at the Army's Edgewood Arsenal responsible for vest design had developed a garment made of seven layers of Kevlar fabric for use in field trials. During this preliminary testing, environmental trials determined that the penetration resistance of Kevlar was degraded when wet. The bullet resistant properties of the fabric also diminished upon exposure to ultraviolet light, including sunlight. Dry-cleaning agents and bleach also had a negative effect on the antiballistic properties of the fabric, as did repeated washing. To protect against these problems, the vest was designed with waterproofing, as well as with fabric coverings to prevent exposure to sunlight and other degrading agents.
The third phase of the initiative involved extensive medical testing to determine the performance level of body armor that would be necessary to save police officers' lives. It was clear to researchers that even when a bullet was stopped by the flexible fabric, the impact and resulting trauma from the bullet would leave a severe bruise at a minimum and, at worst, could kill by damaging critical organs. Subsequently, army scientists designed tests to determine the effects of blunt trauma, which is injuries suffered from forces created by the bullet impacting the armor. A byproduct of the research on blunt trauma was the improvement of tests that measure blood gases, which indicate the extent of injuries to the lungs.
The final phase involved monitoring the armor's wearability and effectiveness. An initial test in three cities determined that the vest was wearable, it did not cause undue stress or pressure on the torso, and it did not prevent the normal body movement necessary for police work. In 1975, an extensive field test of the new Kevlar body armor was conducted, with 15 urban police departments cooperating. Each department served a population larger than 250,000, and each had experienced officer assault rates higher than the national average. The tests involved 5,000 garments, including 800 purchased from commercial sources. Among the factors evaluated were comfort when worn for a full working day, its adaptability in extremes of temperature, and its durability through long periods of use.
The demonstration project armor issued by NIJ was designed to ensure a 95 percent probability of survival after being hit with a .38 caliber bullet at a velocity of 800 ft/s. Furthermore, the probability of requiring surgery if hit by a projectile was to be 10 percent or less.
A final report released in 1976 concluded that the new ballistic material was effective in providing a bullet resistant garment that was light and wearable for full-time use. Private industry was quick to recognize the potential market for the new generation of body armor, and body armor together with bulletproof vests became commercially available in quantity even before the NIJ demonstration program.
Extracts from a National Institute of Justice Report