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Introduction to Bullet-Resistant Materials

Purpose

 

Bullet-resistant materials are commonly used where the threat of attack by an armed criminal is likely. While the level of security risk at most facilities doesn't warrant the use of such materials, some facilities, due to the nature of their operation or their location, do find the use of bullet-resistant materials to be a necessary security precaution.

 

Bullet-resistant materials can both protect employees as well as discourage robbery attempts and other types of crimes involving the use of a firearm. Bullet-resistant materials are commonly used at banks, pharmacies, check cashing centers, and other businesses that handle cash or narcotics in high-risk neighborhoods. Bullet-resistant materials are also used at public facilities such as police stations, jails and courthouses.

 

In recent years, certain types of facilities that didn't previously use bullet-resistant materials are now using them. For example, hospitals in high-crime areas now use bullet-resistant materials on the exterior of their Emergency Departments to protect against gang-related drive-by shootings. Also, some data centers now install bullet-resistant materials in their lobbies to prevent forced takeover of the facility by armed attackers.

 

Type of Bullet-Resistant Materials

 

There are four main categories of bullet-resistant materials: bullet-resistant glazing, bullet-resistant panels, bullet-resistant doors, and bullet-resistant accessories.

 

Bullet-Resistant Glazing

 

Bullet-resistant glazing is probably the best known type of bullet-resistant material. Bullet-resistant glazing is used when ballistic protection is needed, but direct visual contact is also required between the protected area and the non-protected area. Bullet-resistant glazing is commonly used at bank teller cages and other types of service counters, providing protection between the public area and the area that contains the cash or other valuables. Bullet-resistant glazing is also used on the interior of lobbies, providing separation between the public and non-public side of the lobby. In addition, bullet-resistant glazing is sometimes used on the exterior of the building to protect against stray gunfire or attacks from a sniper.

 

There are four commonly used types of bullet-resistant glazing, each with their own advantages and disadvantages. The following is an overview of each type of material:

 

Laminated Glass

  • Consists of multiple layers of glass laminated with protective interlayer, usually polyvinyl butyral (PVB).
  • Least expensive type of bullet-resistant glazing.
  • Suitable for both indoor and outdoor use.
  • Scratch-resistant.
  • Because it is glass, it can be broken, and does not provide protection against a sustained physical attack.
  • Heaviest type of bullet-resistant glazing; weight may require special structural considerations.

 

Acrylic

  • Suitable only for indoor use.
  • One-half the weight of glass.
  • Scratches relatively easily unless provided with special coating.
  • Available only in lower ballistic ratings.
  • Offers some degree of protection against physical attack.

 

Polycarbonate

  • Suitable only for indoor use.
  • Weighs less than glass.
  • Best ability to fully capture incoming bullet, prevents ricochets and spalling.
  • Offers protection against physical attack.
  • Has slight grayish tint; not as clear as glass or acrylic.
  • Scratches relatively easily.
  • Costs more than laminated glass.

 

Glass-Clad Polycarbonate

  • Consists of polycarbonate with a layer of glass added to it.
  • Suitable for indoor and outdoor use.
  • Glass side resists scratching and provides weather-resistance.
  • Weighs less than glass.
  • Offers protection against physical attack.
  • Has slight grayish tint; not as clear as glass or acrylic.
  • Costs more than laminated glass.

 

Bullet-Resistant Panels

 

Bullet-resistant panels are most commonly used to protect the walls surrounding the openings where bullet-resistant glazing is used. For example, if bullet-resistant glazing was used at a customer service window in a pharmacy, bullet-resistant panels would be used in the wall on both sides of the window as well as below and above the window itself.

 

The use of bullet-resistant panels allows walls to be constructed using standard stud-wall construction techniques rather than requiring that a concrete or masonry wall be provided. Bullet-resistant panels are typically fastened to the studs and then covered with regular drywall. When painted, the bullet-resistant wall looks like any other.

 

There are two popular types of bullet-resistant wall panels: steel, and fiberglass composite. Steel wall panels are the least expensive but weigh more. Steel wall panels are difficult to work with on the job site and usually must be ordered from the factory in the desired size. Fiberglass composite wall panels cost more than steel wall panels but weigh about half as much. Fiberglass composite panels are much easier to work with and can be cut and drilled on the job site.

 

Bullet-Resistant Doors

 

Bullet-resistant doors are used when a door is required in a wall that forms part of a bullet-resistant barrier. Bullet-resistant doors are specifically designed to provide ballistic protection and usually come as a complete unit consisting of both door and door frame. Bullet-resistant doors come in both wood and metal versions and are available with or without windows.

 

Bullet-Resistant Accessories

 

Bullet-resistant accessories are used when it is necessary to pass objects through a bullet-resistant barrier. Bullet-resistant accessories are also used to allow direct audio communications between both sides of the barrier. Bullet-resistant accessories include speak-through devices, money trays, gun ports, and package receivers that allow packages of various sizes to be passed through the barrier.

 

Ballistic Ratings

 

Bullet-resistant materials are sometimes incorrectly called "bullet-proof" materials. Most of these materials are in fact not bullet-proof, but only provide protection against a certain range of types of firearms for a certain period of time.

 

Firearms are available in a wide variety of calibers, each which have a different ability to penetrate a bullet-resistant material. Even within cartridges of the same caliber, there are different bullet weights and types and different powder loadings. Rifle cartridges generally have much more power than handgun cartridges, and shotguns may pose a different type of threat than either handguns or rifles. Repeated gunfire against the same surface also has a different effect than a single bullet does.

 

To help sort through all of these variables, Underwriters Laboratories (UL) has developed a written standard, UL 752, that establishes ratings for bullet-resistant materials. UL 752 specifies eight levels of bullet-resistant ability, ranging from Level 1 to Level 8. The most common ratings used by commercial businesses are:

  • Level 1 - Provides protection against 9mm and less powerful handgun cartridges.
  • Level 2 - Provides protection against .357 magnum and less powerful handgun cartridges.
  • Level 3 - Provide protection against .44 magnum and less powerful handgun cartridges.
  • Level 4, 5, 7, and 8 are generally needed to provide protection against common rifle cartridge calibers. UL 752 also has supplementary ratings for threats from a shotgun.

 

In general, the higher the rating level, the better the protection, but the greater the cost. Higher rated materials are also generally thicker and weigh more, and there may be a limited availability of materials and accessories at the higher rating levels.

 

Suggestions for Using Bullet-Resistant Materials

 

  1. The decision to use or not use bullet-resistant materials should only be made after a comprehensive security assessment has been conducted. The security assessment should provide guidance as to where bullet-resistant materials should be used, and establish the minimum UL rating level required based upon the level of risk at the specific facility.
  2. A systems approach must be taken when designing a bullet-resistant barrier; the wall, glazing, and any accessories must all be rated to provide the minimum desired UL rating level. It doesn't make sense to provide a Level 3 rated window when the wall surrounding the window is unprotected. Also consider the possibility of ricochet and the potential for a bullet to penetrate the adjacent walls, ceilings, and floors.
  3. Always use materials that are UL listed and labeled. Some manufacturers can be deceptive and use terms such as "tested to UL standards", "meets requirements of UL Level 3", etc. even though their products haven't actually been tested by UL.
  4. The thickness and weight of bullet-resistant materials can have an impact on building construction and may affect everything from the size of the structural beams to the type of window coverings used. Be sure to involve your architect or other design professional in the planning of your bullet-resistant system.
  5. Employee security awareness training must be provided in conjunction with the installation of a bullet-resistant barrier. Employees need to know how to react when a weapon is presented, even if they are behind a protective barrier. Employees may also be at increased risk when entering or leaving the protected area, and need to be given guidelines on how this can be accomplished safely.

 

 

 

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