We offer this bullet proof vest because it provides the level of protection that most people need, and features large pockets that allow it to be upgraded to a Level III or IV. Most people don't find themselves in situations where they might be shot at by a rifle, but if that is part of your vocation, you will want to upgrade your vest with armored plates. It is important to assess your safety needs realistically when choosing the right bulletproof vest for you.
Close menu. What Kwolek discovered would eventually become Kevlar and would see application in tires, racing sails and bulletproof vests. Bulletproof vests today are made from polyethylene fibers — a popular plastic polymer seen in nearly everything we use: grocery bags, toys, plastic trash bins and so on.
Polyethylene fibers or "PE" as it's called , are woven in layers to form the guts of a protective vest that is cheaper and stronger than Kevlar. Originally used for sail cloth, the polyethylene fiber is now used to make lighter, yet stronger, non-woven material for use in bulletproof vests alongside the traditional Kevlar. According to Tom Nardone, president and founder of BulletSafe , a manufacturer of bulletproof vests, the layers inside a vest are designed to reduce the velocity of a round to a point below supersonic — faster than the speed of sound — so the fibers can have time to react to the bullet and exert their toughness on the bullet.
The more layers, or the greater the density of the weaving of layers, the greater the toughness of the fibers — a measure of their strength and how much they will bend before they break — and the more capable they are of stopping a bullet. Most pistols fire bullets at velocities that are slightly above the speed of sound. Slugs from shotguns travel even slower. A good vest doesn't need to work hard to bring a 9mm bullet or shotgun shell's velocity down to a point where it can make use of the toughness of its fibers.
A rifle bullet, however, is another matter entirely. It'll take a far greater density of ballistic fiber to stop that bullet. Most vests designed to stop rifle bullets are backed up with high density insert plates made from ceramics and polyethylene to break up a bullet into pieces and capture it. The material of the vests themselves is also prone to break down for various reasons.
Kevlar, for instance, degrades when exposed to salt — such as the salt in human sweat. The longer a person exerts themselves while in a bulletproof vest made of Kevlar — to the tune of years — the greater the likelihood of failure.
Vests made from PE also will break down over time when exposed to UV light. The side of the shell facing the body is usually made more comfortable by sewing a sheet of some absorbent material such as Kumax onto it. A bulletproof vest may also have nylon padding for extra protection. For bulletproof vests intended to be worn in especially dangerous situations, built-in pouches are provided to hold plates made from either metal or ceramic bonded to fiberglass.
Such vests can also provide protection in car accidents or from stabbing. Various devices are used to strap the vests on. Sometimes the sides are connected with elastic webbing. Usually, though, they are secured with straps of either cloth or elastic, with metallic buckles or velcro closures. Some bulletproof vests are custom-made to meet the customer's protection needs or size.
Most, however, meet standard protection regulations, have standard clothing industry sizes such as 38 long, 32 short , and are sold in quantity. Bulletproof vests undergo many of the same tests a regular piece of clothing does. The fiber manufacturer tests the fiber and yarn tensile strength, and the fabric weavers test the tensile strength of the resultant cloth.
Nonwoven Spectra is also tested for tensile strength by the manufacturer. Vest manufacturers test the panel material whether Kevlar or Spectra for strength, and production quality control requires that trained observers inspect the vests after the panels are sewn and the vests completed.
Bulletproof vests, unlike regular clothing, must undergo stringent protection testing as required by the National Institute of Justice NIJ. Not all bulletproof vests are alike. Some protect against lead bullets at low velocity, and some protect against full metal jacketed bullets at high velocity. Each classification specifies which type of bullet at what velocity will not penetrate the vest. While it seems logical to choose the highest-rated vests such as III or IV , such vests are heavy, and the needs of a person wearing one might deem a lighter vest more appropriate.
For police use, a general rule suggested by experts is to purchase a vest that protects against the type of firearm the officer normally carries.
The size label on a vest is very important. Not only does it include size, model, style, manufacturer's logo, and care instructions as regular clothing does, it must also include the protection rating, lot number, date of issue, an indication of which side should face out, a serial number, a note indicating it meets NIJ approval standards, and—for type I through type III-A vests—a large warning that the vest will not protect the wearer from sharp instruments or rifle fire.
Bulletproof vests are tested both wet and dry. This is done because the fibers used to make a vest perform differently when wet. Testing wet or dry a vest entails wrapping it around a modeling clay dummy. A firearm of the correct type with a bullet of the correct type is then shot at a velocity suitable for the classification of the vest. Each shot should be three inches 7.
Six shots are fired, two at a degree angle of incidence, and four at a 0-degree angle of incidence. One shot should fall on a seam. This method of shooting forms a wide triangle of bullet holes. The vest is then turned upside down and shot the same way, this time making a narrow triangle of bullet holes. To pass the test, the vest should show no sign of penetration. That is, the clay dummy should have no holes or pieces of vest or bullet in it.
Though the bullet will leave a dent, it should be no deeper than 1. When a vest passes inspections, the model number is certified and the manufacturer can then make exact duplicates of the vest.
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