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1. General Questions about Protective Vests2. Questions about ballistics3. Questions about design / ergonomics / comfort 4. Questions about individual materials5. Questions about services provided by MVS
1.1 How do protective vests stop bullets?

Textile fabrics produced from yarns that consist of extremely high tensile strength filaments are used in protective vests (e.g. para-aramid, HPPE, PBO). These materials can defeat “normal” revolver or pistol bullets when fired from “normal” hand guns. The bullet hits the ballistic panel, which is generally produced using many layers of either woven fabrics or crossplied unidirectional yarns. The yarns which are hit directly are mostly destroyed, removing some of the energy of the bullet principally long and crossways across the fabric. At the points where yarns cross, the bullet energy is further weakened and the remaining energy is distributed to the surrounding yarns. Thus the energy reaches more and more yarns until eventually it is exhausted by the resistance of the tough material. Part of the energy is also taken up in the deformation of the bullet which is sometimes completely squashed flat. The composition of the yarn (the fineness and the number of the single filaments employed) plays an important part here. The finer the yarn and the greater the number of fabric layers, the more filaments are contained in the structure and the greater the amount of energy that can be absorbed. The strength and the “modulus” (the relationship between tensile strength and elongation) of the thread used are of utmost importance; so too are the manufacture of the fabric, (e.g. the weave setting, weave pattern, areal weight and finish) and the number of layers of fabric used and their connection to one another (Soft Ballistics).

To defeat high velocity bullets such as fired from rifle’ s and machine guns and / or with a very hard core or jacket you not only require the pure textile materials but also hard elements of metal, ceramic or compressed textile material which are able to offer appropriate protection (Hard Ballistics).

1.2 How can you tell the protection level of a protective vest?

Each vest is appropriately marked on the protection panel.

The label indicates the technical guidelines on which the protection is based e.g. “Technische Richtlinie Schutzwesten der Deutschen Polizei” (in English,“The German Police Technical Guidelines for Protective Vests”),  “NIJ Standard 0101-04”, PSDB Protection Level or other national standard and the level in the corresponding protection class e.g. “Protection class 1”, Level III-A”, or HG2 etc. If the inner section of the vest consists of several elements each protective insert is labelled, giving instructions for combined use with other elements and indicating the correct sequence of positioning of the elements.

1.3 How heavy is a normal protective vest and how long can one be worn without comfort problems?

Depending on the size, the design and the protection requirements the weight of a protective vest can vary enormously. 

A medium-sized covert vest commonly used by Police Officers weighs between 2 and 3 kg. The weight can be noticeably reduced by the use of innovative ballistic materials and cover materials. The wearer’s subjective feeling of comfort is largely dependent on such criteria as flexibility, optimised cut and heat-regulating cover materials.    

Many different factors influence the length of time a vest can be worn; the personal attitude and physical constitution of the wearer, prevailing climatic conditions and whether one is accustomed  to wearing protective vests.

The protective vests as worn in the army and special units, which must generally offer protection against rifle fire and protect a relatively large area of the body, can weigh up to 15 kg or more. 

1.4 What accessories are available for protective vests?

We can supply the following accessories: replacement covers, carrying bags, stab protection elements and additional protectors for increasing the protection class.

For covert vests we have special shock absorbers for the heart and spinal areas and a sweat-control T-shirt. For overt vests there are additional protection elements available for the neck, shoulder, upper arm, thigh and groin. 

For many overt vests there are additional inserts for up-armouring to higher protection classes.

1.5 What happens on impact of a bullet? What effects can a wearer expect when a bullet impacts?

The amount of damage caused by a projectile largely depends on  what kind of projectile it is, its speed and its angle of impact. The effect on the vest wearer, that is to say the risk of injury, depends on the relation between the protection class of the vest and the type of bullet. If the “right” one has been chosen i.e. the one that is suitable for stopping the corresponding bullet, then the wearer has nothing to fear within the protected area besides so-called “blunt trauma”. The effects of the trauma can be somewhat compared with those of a hard punch with the resulting bruising.

The individual’s physical constitution and the position of the hit can of course lead to different results and perceptions.

1.6 How can you tell a good quality protective vest?

First and foremost, a good protective vest must provide reliable protection against the user-defined potential threat, completely fulfilling the requirements of the particular protection class. In addition to these requirements there must be an extra safety margin.

Besides these vital aspects there is a large set of criteria with which to judge the quality of a protective vest. The so-called “comfort criteria” are as important because they ensure that the vests can really be worn continually while on duty, without putting a strain on the wearer. These criteria include such things as weight, the cut of the vest and freedom of movement. Unfortunately, if the vests are solely to be judged on the basis of the comfort criteria the area of protection is mostly very small. It is therefore important to reach a good compromise solution after discussions with the user. Last but not least, the vest must be reasonably priced.

2.1 How is ballistic protection defined?

The ballistic protection or protection level of a vest is defined according to classifications which are based on corresponding specifications. These are, for example, the German police force’s ‘Technische Richtlinie’ (Technical Directive), the US National Institute of Justice standard, the British Centre of Applied Science and Technology standard and many other sets of country-specific requirements.

There are also special specifications that fall outside these standards. Generally the requirements of the individual national guidelines are based on the most probable threats to be confronted in that country. Risk assessments, conducted over many years, very often form the basis for the definition of the required protection level.

2.2 Who determines the protection level of a vest?

In general the user must determine the protection level of a vest. This can mean the wearer him/herself when only one vest is required. When a government authority places an order the requirements are laid down exactly in the technical specifications. As not every individual purchaser has sufficient information about potential threats it is often advisable to refer to the national technical guidelines. As a rule the required protection level corresponds to the current potential threat in that particular area. There are large differences in requirement profiles, particularly geographically, whereby the commonly used calibre and bullet types vary greatly from country to country. The protection classes ultimately dictate what ammunition type a protective vest must stop and under which test conditions. These classes are generally determined by government scientific institutes or by institutes acting for the government.

2.3 What standards are there?

The most well-known and internationally relevant protection class standards for bullet protection are:

the German police force’s ‘Technische Richtlinie’ (TR – Technical Directive) with its SK1 to SK4 protection classes plus a variety of special stipulations, the NIJ-I to NIJ-IV standards issued by the American National Institute of Justice, the English CAST (the Centre of Applied Science and Technology) standards HG1, HG1a, HG2, HG3, RF1, RF2, and SG1 and the VPAM (Association of Test Centres for Attack-Resistant Materials and Designs) testing standard, which is applicable in many countries, including Germany, Austria, Switzerland, Holland, Belgium and Norway.

2.4 What differences are there between German and American protection classes?

The main differences between the German and North American standards (NIJ) are the testing methods, the different division into protection classes and the differing bullets that are used.

Unlike the American standard, the German directive calls for what is known as a ‘point blank’ shot where the weapon is pushed against the specimen with a force of 100Nm as it is fired. 

Furthermore in the case of the German standard angled firing is done at an angle of 25°, compared to 45° and 60° for the American test. The tests required in the German standard with the protective elements conditioned at -20°C and +70°C do not form any part of the NIJ specification. The bullets used are also not identical. In the very common protection classes, for example, which get compared most frequently (the German protection class 1 and the NIJ level III-A) no firing is carried out in the German specification using a .44 Magnum. On the flip side, the 9mm bullets used are not identical. Due to its steel jacket, the DM41SR prescribed in the German ‘TR’ is much more aggressive than the 9mm bullet used in the NIJ standard.

There is a similarly marked difference in the case of protection class 4 compared to the NIJ’s level IV. While the protective insert is subjected under the German standard to a test using 3 shots, the North American standard calls for just a single shot. Here too the bullets used behave differently.

2.5 Which vest for which calibre?

As an all-round manufacturer of ballistic protective vests MVS is able to supply an exactly defined and certified protective panel for all normal types of ammunition available on the market. Generally we can supply a relatively light textile vest for protection against most pistol and revolver bullets. Steel, ceramic or composite panels are, however, required to stop hard core ammunition and rifle fire. 

The ballistic panel of each type of protective vest is developed according to the defined potential threat. Through our own research and development and in close collaboration with the materials supplying industry we develop permanently optimised and reduced-weight ballistic protective structures.

2.6 What does the “V50” of a ballistic panel indicate?

The V50 indicates the bullet velocity at which you can expect a 50% chance of a stopped shot and a 50% chance of a penetration shot. In order to determine this value several stopped and penetration shots are carried out within a limited range of velocities. In order to establish the “V50” 3 stopped and 3 penetration shots are required. In this test method penetration shots are intentionally caused in order to establish the critical bullet velocity, known as the V50 value for the tested armour. 

2.7 What are the effects of a defective ballistic panel?

Problems associated with UV rays, water absorption, hygiene)4A defective protective envelope does not immediately effect the ballistic protection provided by the panel. It is only when the panel becomes moist or wet that the ballistic performance may be reduced.  Should the amount of water absorbed by the panel reach high levels (e.g. > 15%) the probability of penetration can become far greater. The effect of the water can be best likened to that of adding a lubricant; if the panel is correctly dried to normal moisture levels the ballistic performance is completely restored. All MVS ballistic panels are encased in protective water resistant envelopes which are usually welded providing water tight protection.

UV rays can also have negative effects on the panel; in this case, however, the damage is irreversible. For this reason the used armour panel covers are made of UV resistant material.

According to today’s state of knowledge a small amount of perspiration entering a panel does not lead to a reduction in the ballistic performance, however this should be prevented for hygienic reasons as the moisture combined with body warmth provides ideal conditions for all types of microbes and fungi. It is also important to note that the ballistic panels cannot be washed; only the panel cover can be wiped clean. A damaged panel cover should be replaced as soon as possible. 

2.8 What is “blunt trauma”?

A blunt trauma describes the minor injury which can occur when someone wearing a protective vest is shot. The result is bruising or in bad cases internal injuries or broken ribs. In these cases the bullet does not penetrate the panel, but the force of the panel on the body causes these injuries. The severity of these injuries depends on the force and angle on impact, the physical constitution of the wearer and the part of the body which is affected.

2.9 What is a shock absorber?

A shock absorber helps to reduce blunt trauma and the related injuries. A shock absorber consists of materials which, due to their composition, can either absorb energy quickly and distribute it over a large area (e.g. laminated plates, plastic foils or metal) and/or provide volume so that they act as a buffer in front of the body (e.g. hard foams and feather down etc.)

Shock absorbers can be produced in many forms and sizes. There are two main types; partial shock absorbers for the heart and spinal areas and full-sized absorbers which have the same form and size as the ballistic panel.

2.10 Does a protective vest also stand up to stab attacks? What is required for stab protection?

A solely textile ballistic protective vest without hard ballistic inserts can only resist stab attacks to a limited extent. While bullet resistant vests provide very good protection against slashes, the protection may be insufficient for true stab attacks.  

Special measures are necessary to provide protection in such cases; MVS supplies separate stab protection inserts for all vest types. The stab protection elements, which are placed in front of the ballistic panels, can be adapted to the shape of any vest type.

Usually these inserts are only fully effective when combined with a ballistic panel; this is then noted accordingly on the stab protection insert.

2.11 Can stab protection be added to all protective vests?

Basically every vest, at least every Mehler vest, can be up-armoured for stab protection. According to the instructions on the the stab protection element it is either inserted in front of the ballistic panel or pulled over it.

2.12 Composition and weight of stab protection inserts?

Today there are many different types of stab protection inserts which have very different properties. Inserts made of materials such as sheet steel, titanium foil or segmented metal plates tend to be rather inflexible, and are seldom used by informed users.

MVS has opted for more flexible materials; in particular a specially treated and constructed steel chain mail. Many police units are now using this type of protection.

Solutions based on specially coated or laminated aramid fabric are also possible, particularly when ballistic and stab protection are to be inseparably combined.

Such a solution also provides very good protection against numerous very pointed weapons (e.g. spikes, needles and sharpened bicycle spokes). As per protection class ST (25 J) specifications, additional weight of approx. 1-2 kg must be expected.

2.13 Do protective vests lose their protective qualities when wet?

Ballistic performance is reduced when water is absorbed by ballistic panels.

The way moisture affects protective inserts on impact of a bullet is relatively complex and difficult to explain in just a few words. 

It is better if the contents of the protective inserts are sealed against the ingress of water.

A protective vest manufacturer like MVS aims to reduce water absorption. This is achieved by treating the protective materials with an appropriate water-repellent or by sealing the panels, for example, in water-proof covers. 

2.14 Why must a ballistic panel be sealed in a waterproof cover?

Even if the integrated safety margin proves to be sufficient during “wet shots” we are convinced the protective panel must be sealed in a waterproof cover.

In contrast to the outer cover, the ballistic panel is not designed for washing in a conventional washing machine. The combination of warmth and moisture, perspiration which has entered a panel, creates ideal conditions for micro-organisms. Should bacteria or fungi spread within the panel no counter measures can be taken. MVS stops moisture from entering the panels by sealing them. This also allows the surfaces to be cleaned with a damp cloth.

2.15 What do protection classes 1+ and 4+ mean?

These are not official protection categories of the German protective vests standard. Rather, they are terms that get used to classify calibres/threats not included in classes 1-4. Unfortunately there are varying interpretations as to what an ‘SK1+’ or an SK4+’ represents.

What very often gets used for the ‘SK1+’ interpretations is the 7.62 x 25 VMR/WK (Tokarev), made in Russia, weighing 5.5g and with a speed of 500 +-20m/sec. The Tokarev hard core (iron core) is, on the other hand, very difficult to stop with a flexible structure as basic protection. Whether you can still call such structures flexible is questionable. 

Similar confusion is caused by the term ‘SK4+’. What is meant here in most cases is the Russian-made 7.62 x 54 R VMS/HK-Brand B32.  The speed as special protection is specified in the German protective vest standard as 860 +-10 m/sec. Based on our experience it would already be possible to stop a single shot of this calibre with a high-quality SK4 panel. Assuming the specification of firing 3 shots at the panel as per the German standard, the panel structure needs to be designed accordingly. 

Another bullet often associated with ‘SK4+’ is the 7.62 x 51 VMS/HK with a tungsten carbide core (e.g. 7.62 x 51 VMS/HK FFV APHC from Bofors). To stop this bullet, which has an extremely hard core, requires a relatively strong structure made of special high-performance ceramics.

3.1 Can wearing the protective vest be expected to impair freedom of movement?

Depending on the protection class, structure and cut of the vest, impaired freedom of movement is to be expected to a greater or lesser degree. This is comparable to wearing an additional heavy piece of clothing. This effect is unavoidable. However, it can be reduced through good design, optimised cut and the use of technically optimised ballistic materials (fabric treatment and interlayer construction). 
In terms of the vest’s cut the right compromise has to be found between comfort and safety (size of the protected area). 

3.2 What can be done about excessive heat and perspiration?

As vests generally do not let air through, wearing a protective vest can, after some time, lead to sweating. This effect can be delayed a little by wearing a sweat-control T-shirt under the vest and also by good vest design: it cannot, however, be totally avoided.

There is no ready-made solution to this problem as the moisture absorbed by the T-shirt as well as the trapped heat can only be partially conducted to the outer surface of the vest.

In many cases it is sufficient to loosen a tight fitting vest to relieve any discomfort. 

Three-dimensional textiles, that create gaps between protective vest and body will only be able to help reduce the build-up of heat if it is also ensured that the air that warms up in the gaps is able to escape to the outside. In most if not all cases this can only be achieved via active ventilation. As air is a good thermal insulator, it is, on the other hand, possible that the textile structure creating the gaps may even cause the wearer to get hotter. In that case it is advisable to compensate for the body’s loss of fluids as a result of sweating by a higher consumption of liquids.

3.3 What shape can a vest have? Is the shape important?

The shape of the vest is crucial for both comfort and safety. The best possible solution for the specific requirements of the user must be found.

Clearly the larger the vest, the larger the area of the body which is protected; this means more safety. But a large protective area also means much less freedom of movement and comfort. 

It must be possible to wear, for example, a covert vest for several hours a day so the compromise between protection and comfort is a very important one; ultimately it is a decision which is taken by the user.

3.4 In which colours are the vests available?

Depending on the amount to be ordered and the type of cover material required there is a large range of colours possible. Sometimes the choice of the colour is restricted by considerations regarding the other elements of a vest cover (e.g. belts, zips, buttons) the colour of which should match the cover material as well as possible.

MVS has customers from all over the world, and responding to their different colour preferences, has built up a wide range of standard colours. Please contact our sales team for details of our current range.

3.5 Do you also make vests to measure?

An exact fit is essential for optimal protection and comfort. The size scheme used by MVS provides a choice between several sizes and accounts for a large proportion of body sizes.

We at MVS have followed the trend towards individually fitted vests and over the last few years we have measured many thousands of users and produced the appropriate vest sizes. The organisation of the measuring task varies greatly from customer to customer. Either trained MVS staff take the measurements on site, or police staff are trained for this task (e.g. clothes store staff), or police staff learn the measuring methods from a demonstration video.

The degree of service we provide is according to our customers’ wishes and is integrated in our offer.

4.1 Which materials are suitable for the production of ballistic panels?

In the case of soft ballistics textile fibres of para-aramid with a high tensile strength (e.g. Kevlar or Twaron) or high-tenacity polyethylene (e.g. Dyneema or Spectra) are used.

These materials are woven or integrated in layers of unidirectional fibres to provide protection against many common pistol and revolver bullets. In addition there are various plastic materials which are used for shock absorbers which cover certain vital areas of the body or the whole protected area.

Often it is possible to develop a specific ballistic panel for protection against one particular potential threat by using an optimal combination of the materials mentioned.

In the case of hard ballistics very hard fast bullets (mostly rifle bullets) must be effectively “smashed” by the protective material. Very hard insert plates combined with soft ballistic material are used for this purpose. These plates are mostly of compressed polyethylene, or ceramics (e.g. Aluminium Oxide, Silicon Carbide, B4C) with a suitable backing. The choice of material depends on the potential threat. The only real solutions for extremely hard and penetrative bullets are ceramic plates due to their relatively high hardness.

4.2 Which cover material for which application?

There are no real restrictions when it comes to the choice of cover material for covert vests. The question here is whether you would prefer maximum comfort or a robust outer cover with reinforcements for durability. As a rule, cotton or cotton/polyester fabric, polyamide/polyester with a fine weave can be worn close to the skin.

MVS ensures through strict checks and in collaboration with suppliers that such fabrics and yarns do not contain any dyes or finishing agents that are harmful to health.

Highly flame retardant materials, such as for example Meta-Aramid NOMEX or FR-treated cotton and cotton blend fabrics can make sense for overt protective vests in certain areas of use. If great importance is placed on the vest being hard-wearing, polyamide fabric (e.g. including Cordura) can be used as the outer cover material or as reinforcement of specific susceptible areas.

4.3 What are the differences between aramid and polyethylene? What is PBO?

The most commonly synthetic fibres in soft ballistics, para-aramid (trade names Kevlar and Twaron) and polyethylene (HPPE stands for High Performance Polyethylene- trade names Dyneema and Spectra) differ according to their chemical composition.

These extremely strong synthetic fibres can be distinguished by their appearance (para-aramid is yellow, HPPE is white). 

One significant difference is that HPPE is used in ballistics almost exclusively as unidirectional layers, while para-aramid fibres are used both as woven fabrics and as unidirectional layers.

The advantages of each material must be weighed up from case to case according to the priorities which have been set. In many cases the differences required in the manufacturing process for the protective inserts (woven fabric or unidirectional layers) is a more decisive factor than the actual difference in the fibre properties. 

Both materials have now been used for protective vests for a relatively long time. HPPE has been used over 15 years, para-aramid over 30 years. 

Comparing the difference between UD layers and para-aramid fabric the panels with UD layers tend to be a little lighter than comparable protective constructions using para-aramid fabric. However, the fabric constructions are more flexible, following the wearers’ different body contours and allowing good freedom of movement. 

The back face signature (BFS) test results and the so-called “multi-hit performance” tend to turn out better for UD layers due to their higher stiffness. UD layers, however, have the disadvantage that they are sensitive to crushing and bending which, in extreme cases, can lead to permanent creasing and the delamination of individual layers.

It is often argued that HPPE, being a thermoplastic material, represents a danger to police officers due to its high inflammability. We do not consider this a real potential danger as the ballistic panel is covered both by the vest cover and in the case of a covert vest the clothes worn above it. However, in order to deal with this problem a flame retardant outer cover can be ordered if desired.

The bullets that are required to be defeated determine the choice of HPPE or aramid to a large extent, certain bullets tend to be defeated better by aramid, others by HPPE.

In addition to para-aramid fabrics and HPPE, a few years ago another very strong fibre-PBO (brand name: Zylon) was also used for protective vests. Due to the aging that occurred (within a few years the strong fibres showed a significant reduction in strength), PBO proved unsuitable for use in protective vests and has now almost completely disappeared from the market for ballistic protection.

5.1 Can MVS replace the panel covers and outer covers which are currently in use (also from other manufacturers)?

Yes, as long as no intellectual property rights apply to the outer covers or panel covers supplied by third-party manufacturers, MVS can also offer such covers. Should you be interested in this service please let us know the required model, sizes and the quantity you wish us to consider. We would then be pleased to submit an offer.

5.2 How long and for which products does MVS provide a guarantee?

All of the ballistic protection products manufactured by MVS using aramid or HPPE have a warranty of 10 years after the date of production. The guarantee for the outer covers is for up to two years after delivery depending on the type of material used.

If you require further information about our product liability insurance please contact our sales team.

5.3 Can I buy a protective vest from MVS as a private individual?

No. MVS sells its ballistic protection products exclusively to the official security bodies, i.e. the police and miliatary. People with a legitimate interest in ballistic protective clothing (e.g. police officers purchasing for themselves, private security companies or journalists on foreign assignments) can, subject to presenting appropriate documentation (e.g. professional ID), also purchase personal protective vests from our subsidiary company MLE (see link at Company / Group).