What is Kevlar Bulletproof Vest
Bulletproof vests designed to stop the penetration of a bullet and prevent harm to the wearer. Several layers of incredibly strong fibers as Kevalr fibers, stop bullets from penetrating the vest, the vest act as a net by catching kinetic energy from the ballistic bullet. As a bullet attempts to pass through the vest each layer twists to create a barrier, slowing the bullet until it is completely stopped. This process deforms the bullet by flattening it into the shape of a dish and spreads the force of the impact over a large portion of the vest. The impact of the bullet is massive and although the bullet was stopped, the bullet’s energy will be absorbed by both the vest and the wearer.
Is the Purchase of a Bulletproof Vest Legal?
Generally, it is legal to purchase and wear a bulletproof vest for safety; however, individual countries and states have specific laws, so it is always better to verify this information with a local attorney. In some areas special permission can be requested in some locations if you can show proof that a bullet proof vest is necessary for your work or your safety.
Why Kevlar Vest
Kevlar is a lightweight, strong and flexible fabric that is commonly utilized to make bulletproof vests. Invented in 1965 by Du Pont, Kevlar was initially used in tires. Currently several companies choose Kevlar when making body armor and protective clothing. Classified as a para-aromatic polyamide synthetic fiber, Kevlar consists of several inter-chain bonds that help to make it extremely strong. Kevlar forms flat sheets, similar to silk, as its structure consists of quite rigid molecules.
Kevlar remains as a leading anti-ballistic material as it takes a tremendous amount of energy to make a bullet pass through it. The fibers of polymer molecules are tightly woven, making it extremely hard to move apart, meaning it takes a great deal of energy to separate them. The energy from a bullet reduced as it trying to penetrate through the vest. If either of the threats manages to penetrate the material, the speed is reduced considerably, resulting in far less damage. Kevlar is stronger than steel and approximately 5.5 times less dense making it flexible and light enough to wear for longer periods.
Choosing a Bulletproof Vest
When purchasing a Kevlar bullet proof vest, take into consideration two main factors which are the situations you will be wearing the vest in and the level of protection that you will need. Bulletproof vests that manufactured for higher levels of protection are not typically suitable for daily use as they tend to be heavy and bulky.
Determine the Level of Protection Needed
The protection levels assigned to specific body armor are regional, causing variations throughout the world. The US National Institute of Justice (NIJ) is considered to be the world leader in ballistics testing of body armor related to the full range of tests that are performed. They provide details of the testing results in their body armor standards. The body armor standards reveal the range of protection offered by specific pieces that have been tested. Testing results range from low powered hand guns to armor piercing rifle rounds.
Body armor is designed to offer protection against 3 types of threats, including bullet, spike and stab. Protection offered by a bullet proof vest will be dependent upon its ballistic material and is clearly labeled on each vest. When determining which bulletproof vest can provide the higher level of protection, refer to the clearly labeled rating on its tag. The higher the number on the protective equipment, the higher the level of protection it can offer. For example, when comparing two bullet proof vests, the vest labeled as NIJ Level IIIA protection will provide you with a higher level of protection than the vest labeled as NIJ Level IIA and II protection.
Determine the Number of Kevlar Layers Needed
When referencing the previous information in this guide about the ability of Kevlar to reduce the energy that come from bullet, it is easy to determine that a greater thickness of Kevlar related to more layers will provide more protection. Ballistic charts can be referenced on the official site of NIJ that can help you determine the number of layers needed to offer your specific level of protection. The chart illustrates that the more layers you have, the bigger kinetic energy the bullet needs to have to penetrate through the armor. The chart ranks body armor made of various materials on a scale from I to IV related to its ability to provide protection against bullets that were fired from weapons of different power.
To determine the correct number of Kevlar layers in a bulletproof vest first identify the power of the weapon that can be most dangerous to your specific situation and take note of how many Kevlar layers are needed to provide necessary protection, then reference a separate chart to double check if the best protection is offered by type IIA/II or type IIIA armor, etc. The information label on a vest is of importance because not only does it clearly identify the protection rating but it also gives complete details as to model, style, care instructions, date of issue, lot number, a serial number, an indication to which side should face out and a note indicating it meets NIJ approval standards for its specific protection rating.
Quality Control and Testing
To ensure bullet proof vests can provide the level of protection for which they are labeled for, they undergo several tests. The fiber and yarn tensile strength is tested by the fiber manufacturer and the tensile strength of the resultant cloth is tested by fabric weavers. The panel material is tested by the vest manufacturer and quality control requires inspection of the vests after panels are sewn and the vest is completed by trained observers. Testing also includes the vests response to live ammunition to verify level of protection and rating.
Care and Maintenance
The weave of the fabric is one of the main contributors to the level of protection that Kevlar provides. A weave can be interrupted by a spinning bullet causing the force to extend over a large area. Also, over a period of time, the fibers in woven Kevlar begin to separate which reduces the ballistic protection provided by the vest. Therefore, it is highly recommended that Kevlar bulletproof vests be replaced regularly with the majority of US police forces replacing their vests every 5 years.
Kevlar bulletproof vests need to be kept as clean as possible; a cover can be purchased for your vest if it is worn outside of your clothes. Should your vest get dirty you should clean it as soon as you are able. Also, keep in mind that the life of your vest can be shortened if it is worn in hot environments.
Gareth says
Yep, I totally agree with the author. Everything degrades/deteriorates with time. Even these body vests have a label with an expiration date printed on it.
Direct exposures to sunlight, heat, moisture/ water are the factors which affects structural integrity of fiber.
Hurst says
I found this article very informative and useful. Covers up almost all the details you should know about these Kevlar body vests. Thanks.
Marcos says
Flexible soft armor made of Kevlar rated NIJ IIA, II, & IIIA. They stop shotguns and pistols. If you want to stop rifles or ,45 you need to use armor plates.
Eliot says
Interesting and informative! I am planning to buy a Kevlar body vest. Glad I read this article.
John says
Yep that’s true, an NIJ Level II bullet proof vest will provide protection against 9mm handguns, up to .357 Magnums. A bullet proof vest with NIJ Level 3a protection will protect against the same threats as an NIJ Level II vest, and in addition will stop up to a .44 Magnum and 9mm Sub-Machine gun.
Hearn says
I didn’t have much idea how a fiber woven cloth could stop a super-fast bullet. This article helped me to understand the mechanism behind that. Thanks 🙂
Patrick says
It’s an important fact that you should never buy a used bulletproof vest from someone you‘ll never know, just by looking at the outside what this thing could have gone through. It might have lost its ability long before the expiration date.
Kenneth says
I’m just thinking, in some countries or states, how it could be illegal for the civilians to wear body armors? I mean I know it’s a different story for the felons.
Cooper says
If you are unsure about the level of protection you need with the body armor, one easy way to decide is to select the level which at least protect you from your own fire arm.:) There are many incidents of disarming and using it against the owner.
Matthew says
Guys, if you ever need to clean this kind of body armor, only use a damp cloth. NEVER use water or any other chemical directly on the armor.
Samuel says
It’s a fact which rarely anyone notices that the body armor’s length doesn’t reach the waist. If a vest goes past the navel, it becomes heavy at the cost of protecting non-vital organs. An over-long vest will also restrict freedom of movement, a vest that extends past the navel will restrict comfort, and affect the ability to even sit or bend down.
Romero says
I read in an article that Kevlar is preferred over carbon fiber because of Kevlar’s ability to resist sharp material impacts (spikes and stabs) where the carbon fiber often fails.
Hart says
Yes, and the other thing is that it would be extremely uncomfortable to wear a body armor which doesn’t allow the body-heat to be dissipated. I think the heat is even more difficult to handle than the weight. You’ve got to make sure you stay hydrated while wearing it.
Steven says
It’s amazing such a light weight material has that much of strength in it.
Kevlar 1.44 g/cm3 – 3620MPa
Steel 7.8 g/cm3 – 900Mpa
Joe says
Yep, that’s true what the article says about the expiration time of 5 years as of standards. But the fact is that it heavily depends on the way it was used. With enough care when using, you can easily exceed that limit.
Alan says
Author of this article has done a great job summarizing all the facts about Kevlar made body armor. The article provides enough information to understand the theory behind a body-armor, its legal prospective, and the procedure of choosing the proper type, even for a person with a very little knowledge on this subject. Great work!
Clay says
So-called “bullet proof” vests are not really bullet proof; they are bullet resistant.