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Dispelling myths: An introduction to Bullet Resistant Vests

Published: 24th Feb 2021
Author: Deon du Plessis; MD of Bullet Proofing Technology (Pty) Ltd

As in nature, but much, much more quickly, protective garments have to constantly evolve with changing threats. This is the first in a series of articles on bullet resistant vests by Deon du Plessis, MD of Bullet Proofing Technology (Pty) Ltd, which manufactures a wide range of body armour plates and vehicle armour, and supplies a number of other bullet resistant vest manufacturers.

Source: https://www.slideshare.net/zauwad/kevlar-42934354.

BRV stands for Bullet Resistant Vest. This refers to an armoured garment covering the upper body, excluding leg armour, helmets, shields, gloves, boots and eye and face protection. This refers to any jacket or vest worn over or under other clothing to provide the upper body with protection against physical threats, bullets and other ballistic threats. The term “Bullet Proof Vests” is also very often used, and though technically not correct, we all understand the same concept under these different names. It could cover smaller or larger parts of the torso, be lighter or heavier, be flexible or hard, provide a higher or lower level of protection, be worn over or under normal clothing and cost a lot or less. All of these are basically referred to as different types of Bullet Resistant Vests.
 
History
Throughout history “Man” wanted protection from physical threats. It started with rocks, followed by swords, spears, arrows, bullets and explosively launched fragments. At the same time protection evolved from leather and wood, through silk, wool, metals, synthetic fibres and ceramics to modern composites. An ever-developing symbioses developed between ever-increasing  threats countered by ever stronger materials, followed by more energetic, harder, heavier, faster and sharper threats (arrows, spears, swords, bullets, grenade fragments). As the threats evolved, so did the protection and this led to a continual and related development of threats and protection.
The first metal armour suits of the knights of old were developed to provide knights with protection against arrows. Muskets and crossbows were again able to penetrate the first metal suits and the metal was improved and even thickened to again provide protection against musket fire. This made the suits heavier, which made the knights less manoeuvrable and slower and to then being easier targets to hit.
History again repeats itself and even today this is still the case, where the general trend is to use heavier body armour to provide protection against higher threats, which tires the wearer and makes him more vulnerable to attack. How to balance out these contradicting requirements, will be dealt with in the follow-ups in the series.
 

Source: https://www.britannica.com/topic/armour-protective-clothing

 
Brief description of how bullets are stopped in BRVs
Weapons are designed to cause tissue damage and/or disabling blunt trauma to one’s enemy. Tissue damage is mainly caused by physical penetration and/or cutting of the body by sharp instruments such as swords, arrows, spears, knives, axes, spikes, bomb or grenade fragments and, of course, bullets. Many threat types also cause blunt trauma, with or without tissue damage. “Knop-kieries”, batons, axes and rubber bullets are cases in point. There are many occasions where the blunt trauma injury is also as dangerous as tissue damage. For this reason, a decent bullet resistant vest has always had 2 x primary functions, namely stopping body tissue damage (wounds) and also absorbing energy (blunt trauma). This has been so from the first body armours worn right up to modern times.
All professional modern body armour specification thus also defines protection capabilities regarding penetration (tissue damage) as well as blunt trauma. Any testing system needs to also address and measure the protection capabilities on both these of aspects.
Each type of threat is intended to injure the wearer in a specific way. If it is known that the person is wearing body protection, the threat is further optimised to negate the protection capability of the body armour, and to still injure the wearer, despite the body armour. This means that the enemy could aim for unprotected areas, or use weapons with a capability which exceeds that of the BRV. 
Different threats are negated by different techniques. Knives and pangas have sharp and hard edges, so the BRV needs to have a good cutting resistance and be hard or have a tight weave or lamination and should protect the lower abdomen, around the neck and shoulders as well as the vital organs. Normal flexible ballistic material such as Aramid (“Kevlar”) and UHMWPE (“Dyneema” and “Spectrashield”) provides adequate protection against most normally found knives, but special stiletto-knives might require the use of special materials or metal plates.
The bullets from handguns and sub-machine guns travel at relatively slow velocities (300m/s – 550m/s), and if decent soft Aramid (Kevlar) or UHMWPE (Dyneema) is used, it is possible to stop these bullets with multiple layers of soft material. The fibrous yarns of these materials have extremely high tensile strengths in relation to their weight and on a weight basis are only 33% of the weight of the most modern metal plate BRVs of the same panel sizes. As this still provides relatively flexible and light body armour which can be worn for prolonged periods, this is the material of choice for this level of BRVs used by most organised law enforcement forces and defence forces all over the world. These materials provide adequate resistance to deform most bullets, which slows them down to be 'absorbed' in the armour panels. The armour does however need space to deform to do this “deformation” and “absorption”, which can cause blunt trauma damage to the body. Most international specifications do however specify ways to measure these transferred forces to the body and define ways to measure it and what is allowable.
 
 
 
To make a BRV protect against bullets fired from rifles, the BRV becomes more complex, heavier and generally more expensive. In most countries, police forces are not seen as encountering military rifle threats, and their police protection levels are mainly against handguns and/or knives. All military forces and some police and security forces in other countries (like South Africa) do, however, commonly encounter rifle threats. In these cases the BRVs need to provide protection against this higher rifle threat level as well. This might not be relevant to all security branches and duties, but certainly to some. To provide protection against rifle fire, hard materials are required. These can be metal-, ceramic- or hard fibre-based. These hard armour plates can be used on their own to stop the bullets in total (stand-alone), or they can be added to handgun level BRVs to upgrade their protection levels to provide enhanced protection against rifle fired bullets as and when needed (ICW).  By using the hard armour plates as enhanced protection in handgun level jackets, users need only acquire one jacket for both protection scenarios, and add or remove the plates whenever the need arises. They could thus wear lighter and more comfortable BRVs as standard, and only add the extra weight and stiffness of the hard armour plates when they want to. Some special duties or operations will of course require the higher rifle protection levels permanently, but if used in short time-spans or by fit and professional personnel, this should not limit the wearer’s performance too much. 

There are a variety of materials which can be used as hard armour plates ranging from High Hardness Steel (heavier and lower cost), ceramic composites (mainly for armour piercing threats) and UHMWPE (lighter and more expensive).  Hard armour stops rifle bullets either through slowing the bullets extremely fast (UHMWPE), by damaging the bullet severely and by absorbing the energy of the bullet. 

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