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Introduction To Bullet Resistant "Proof" Fiberglass

Posted by John Shriner on Wed, Nov 06, 2013 @ 09:52AM

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Bullet Resistant Fiberglass Panels


In an effort to educate the public and to provide some reference, this article has been written to address some common questions about this product. More information regarding bullet resistant products and materials can be found at



What are bullet resistant fiberglass panels and how are they made?


A bullet resistant fiberglass panel is a composite material made from woven roving

fiberglass and polyester resin. The two are combined (hence the word "composite") in a

process known as "wetting" or "impregnating." The wetting/impregnating process, simply

put, is the process of running the woven fiberglass fabric through a bath of resin. This is

then followed by a process where the excess resin is sloughed off and returned to the

bath. A specific number of layers of the wetted fabric are laid up on top of each other

prior to going into a press. The appropriate number of layers determines the final

thickness and ultimately the UL Level for which the bullet resistant fiberglass panels are

to be rated (more information on the UL spec below). Once in the press, the wetted

fiberglass material is then heated and pressed to remove air and to squeeze the material to

it's appropriate thickness and fiberglass to resin ratio. The significance of this glass to

resin ratio will be further explained in the “how do they work” section below The bullet

resistant fiberglass panel is then removed from the press where it is cut to it's appropriate

size and then packed for shipping or storage.

Another common question that is asked is "Is it Kevlar...?" Kevlar is a brand name for

aramid, a synthetic fabric that has excellent bullet resistant qualities. Kevlar is easily

recognizable by its yellow color. Kevlar is an excellent bullet resistant material in both

it's cloth form (pliable and shapeable) and as a composite (rigid). Kevlar is very light and

very effective as a bullet resistant material and is typically used in bullet resistant vests

and other applications where weight is a factor. The downside to Kevlar is that it is very

expensive (often 10 times that of fiberglass) and is hard to cut and drill since the fabric

itself tends to fray. Bullet Resistant Fiberglass Panels are the most cost effective

solution for bullet proofing where weight is not a factor.


How do bullet resistant fiberglass panels stop bullets?


Bullet resistant fiberglass panels defeat a projectile through two physical phenomenon

that occur within the panel as it is impacted by the projectile. The first phenomenon that

occurs is the blunting and spreading of the projectiles energy. This occurs when the bullet

strikes the hard surfaces of the bullet resistant fiberglass panel. The hard face of the panel

flattens (blunts) the leading edge of the projectile (bullet) and thus causes the area of the

impact to spread exponentially thus spreading the force. The same theory applies when

using a can opener (small area) on a steel can vs. trying to use something like a spoon

(large area). The second phenomenon that occurs in bullet resistant fiberglass panels is

known as delamination. Once the blunted bullet begins to enter the bullet resistant panel,

the force of the entering bullet causes the various layers of the panel to separate

(delaminate). This process of delamination spreads the force of the entering bullet across

the area of delamination. This creates a virtual trap / web that decelerates the projectile to

a stop by absorbing the energy of the bullet into the bullet resistant fiberglass panel. As

mentioned earlier, a precise ratio of glass to resin is required to allow the delamination

process to occur. In typical fiberglass construction (cars, boats and other construction)

delamination is not a desirable trait. However, for bullet resistance, delamination is the

mechanism by which fiberglass armor is able to stop bullets.


How do you install bullet resistant fiberglass panels?


Although the applications for bullet resistant fiberglass panels may vary, typical

construction using bullet resistant fiberglass panels is quite simple. For typical

construction applications, the fiberglass armor would be cut to size and anchored to the

2'x4' framing using construction adhesive (liquid nails) and 1-3/4" wood screws. Self

tapping drywall screws work best when affixing to a steel stud. Fiberglass armor can be

cut using a diamond blade edge saw blade and/or a masonry concrete blade. The process is

very slow and creates a fair amount of fiberglass dust which can cause skin irritation.

The Hilti Dry-Cutting Diamond Disc (DC 7 x .086 x DM/MC) for use with skill saws at

8500 RPM is an excellent choice for cutting fiberglass armor. Pre-drilling holes can be

accomplished with a cobalt tip drill bit at medium speed using medium pressure. Should

you chose to laminate your bullet resistant fiberglass panels, it is recommended that you

rough the surface using 120 grit sand paper using medium pressure. A two-component

acrylic, water-based adhesive is highly recommend for bonding to fiberglass armor. HB

Fuller company manufactures several products (RK-3850, X-PB and XR-1392) that will

work fine. HB Fuller can be reached at (800) 328-7307.


The seams, where two bullet resistant fiberglass armor panels meet must be re-enforced

with a 4" batten strip. Simply put, a batten strip is a 4" piece of the fiberglass armor

material placed across the seam to compensate for the discontinuity in bullet resistance

where two pieces of fiberglass armor meet. In the unlikely event that a shot were to be

fired at the seam, the batten strip would be in place, behind the seam, to capture the



Since this product is made of fiberglass and the handling and cutting of bullet resistant

fiberglass panels can cause skin irritation, it is recommend that your installers be supplied

with some basic health and safety equipment. The following items are recommended for

worker protection:


1. Cotton or leather gloves should be worn to provide protection from cuts and

abrasions associated with the handling, cutting and drilling of fiberglass armor.

2. Dust Masks, Particle Masks and/or respirators provide respiratory protection

against dust associated with cutting, sanding and/or drilling of fiberglass armor .

Typical products available include the Moldex 2300 Dust and Mist Respirators and

the Drager-Picco 20 Respirator Filter for Dust and Mist.

3. Outer protective wear should also be worn to protect the skin from fiberglass dust

associated with cutting and drilling fiberglass armor. DuPont, Tyvek Protective

Wear is an excellent outer body covering that will protect your workers from

irritating dust.

4. Protective Eyewear must be worn, especially when cutting, sanding or drilling

fiberglass armor.


Bullet resistant fiberglass panels should be stored indoors and under cover, stacked and

off the floor. Fiberglass armor should be protected from sunlight and exposure to

moisture. If moving fiberglass armor with a forklift is needed, panels should be kept

stored on the pallets and original packing they were originally shipped with. This will

help to avoid cracking, chipping, abrading and scratching the panels prior to their



What is the UL752 Specification for Bullet Resistance and why it



Bullet resistant fiberglass panels are manufactured to the UL 752 Specification for bullet

resistant materials. This specification has been set forth by Underwriters Laboratory (UL)

and is the industry standard for bullet resistant materials. The specifications lays out the

specifics on various ammunitions, velocities, number of shots, and a variety of variables

required for material to be UL rated. More information on the UL752 specification can be

viewed at www.ul.com, www.secureallpanels.com/specs.htm or the Protective Structures

website at www.protectivestructures.com. It is very important that any bullet resistant

fiberglass panels be UL Listed. Many manufacturers will attempt to fool the customer by

stating "Meets UL 752 standards..." or some similar verbiage. UL Listed means that the

fiberglass armor has been tested at Underwriters Laboratory and has passed UL's

stringent testing guidelines. Furthermore, UL mandates that bullet resistant fiberglass

panels be randomly tested several times a year. This ensures that a consistent

manufacturing process is being used and that the bullet resistant fiberglass panels

maintain a high degree of quality and integrity. It is worth mentioning that bullet resistant fiberglass is manufactured to meet the UL 752

specification. However, there are many variances in ammunition types and every possible

bullet and loading technique cannot be accounted for. Bullet resistant fiberglass that is

manufactured to UL specifications cannot account for every variance in ammunition.

Often, a different projectile shape, construction or load may greatly affect the bullet

resistant capabilities of the fiberglass armor. "Hot Loads," for instance, are ammunition

rounds that have extra gun powder in the shell to increase the velocity of the bullet.

Energy increases exponentially with increased velocity and small changes in projectile

velocity can greatly affect the effectiveness of any bullet resistant fiberglass panel or any

other bullet resistant material. Furthermore, the UL752 specification does not take into

consideration every ammunition type. Ammunition shape can also have an effect on any

materials ability to stop penetration. Thus, it is necessary to understand that bullet

resistant does not mean bullet proof.


Why not use steel armor instead of bullet resistant fiberglass panels?


Steel plates, for a long time, have been the primary means of providing bullet resistance.

However, bullet resistant fiberglass panels offer many advantages over steel. Bullet

resistant fiberglass panels are non-ricochet and non-spalling, unlike steel. A ricochet

occurs when a bullet strikes a surface and is deflected away from the strike surface. In a

situation where there may be gunfire, such as in a bank, ricochet can be as deadly to the

customers as a penetration could be to the intended target. Non ricochet material, such as

bullet resistant fiberglass panels, captures the bullet and thus prevents ricochet. Spalling

occurs when a bullet penetrates a material, such as steel, and produces shrapnel on the

exiting side. This shrapnel is actually pieces of the steel fragmenting and becoming

airborne. Spalling can occur on either side of the protective barrier thus causing harm to

customers (non threat side) as well as those on the threat side (employees). Steel is both a

ricochet and a spalling material. Fiberglass is both non-ricochet and non-spalling.

Furthermore, fiberglass panels are much easier to cut, do not rust, and do not produce

condensation. Pound for pound, fiberglass armor is the most effective bullet proofing

solution available, where weight is not a factor.


What are some typical applications for bullet resistant fiberglass panels?


Bullet resistant fiberglass panels can be used in a wide variety of applications where

weight is not a factor. It's excellent blunt force resistant qualities and it's one hour fire

rating (when used with drywall) offer exception bullet proofing qualities for the

following applications:


• gun rooms - in home protection and storage for weapons

• panic rooms - in home / office protection from intruder threats and storms

• bullet resistant doors - core material for bullet resistant door applications

• intrusion resistant doors - excellent blunt force resistance for door applications

• in home vaults - in home protection for valuables and documents

• cash transaction areas - protection from gun violence for banks, check cashing

facilities, check-out counters • court rooms - protection for judges, witness stands and jury boxes

• gun ranges - excellent protection from stray gun fire and ricochet

• military applications - armored vehicles, command centers, barracks

• guard houses - protection at secured access points 

Topics: emergency preparedness, workplace violence, emergency procedures, bullet proof glass, workplace violence prevention, bullet resistant glass, schools