Our Testing Methods
We are proud of the product we are providing.
The testing performed to validate the product went well beyond the requirements for normal standardized testing. We wanted to be sure that the product would work, and that our customers would have confidence in its performance. Below, we talk about the testing that was performed – and why we performed it. There is a lot of technical information provided, but hopefully you can follow the story without getting too bogged down in the details.
For people that don’t work in the ballistics industry, understanding the performance of a product can be very confusing. There are a whole host of performance specifications that each have specific applications in mind. In simple terms, each specification calls out a specific bullet fired from a specific weapon, and then details how many bullets the product must stop. It also specifies the way the product is to be held during the test. When you are developing a product, you must decide what specification best matches the product being developed. For example, if you are developing body armor designed to stop bullets fired from hand guns, you would likely choose to test the armor per NIJ standard 0106.01. In this test, the product is placed on clay (a specific clay at a specific temperature) for the test to simulate the body armor being placed on the human body. The clay is then used not only to make sure that the body armor will stop the bullet, but that the dent caused by the panel (we call that back-face-deformation) is lower than the requirement. This test isn’t very applicable for the design of a shield designed to stop bullets fired from hand guns, like our product. In our case, NIJ Standard 0108.01 is much more applicable as it was written, in part, to cover ballistic resistant materials used to fabricate portable ballistic shields.
For testing per the 0108.01 standard, the product is placed in a metal picture frame that provides around 1” of support around the edges of the panel. C-Clamps are then used to clamp the product to the picture frame – one C-Clamp at each of the four corners of the product. The back of the picture frame is open – there is nothing else to support the product. As such, we call that type of testing “in air”. (Testing per 0106.01 is called testing “on clay”.)
NIJ Standard 0108.01 specifies several Types of performance, ranging from hand gun bullets to rifle bullets. Each successive Type is inclusive – to meet a higher Type, the armor must stop the bullets specified by that Type, but also the bullets specified by each of the lower Types. Our product was tested to Type III-A. This means that it will also stop the bullets specified by Types I, II-A, and II. Of the bullets specified up to Type III-A, the most difficult one to stop is the 44 Magnum Lead SWC Gas Checked, so testing is normally performed with this round.
To meet NIJ Standard 0108.01 Type III-A, a single product must be shown to stop 5 bullets in a specified pattern. The impact locations are marked using a standard template and a bullet is placed on each of the marked impact location. The pattern is a square with one impact on each corner and then one additional impact at the center of the square. Standard test panel sizes include 12” x 12”, 15.25” x 15.25”, 16” x 16”, 18” x 18” and 24” x 24”. As you can imagine, larger panels will have an easier time stopping the 5 bullets than smaller panels. In our case, the ballistic shield is 14.25” x 10” and covers 142 square inches. As such, when we performed the NIJ Standard 0108.01 validation testing, we tested 12” x 12” panels (covering 144 square inches) as this is close to the same sized panel. In addition, we tested 5 armor panels rather than just one as required.
During testing, each bullet is assembled on-site. A bullet consists of a projectile (the part that actually hits the armor) that is crimped into a casing after the desired amount of gun powder has been placed in the casing. (The casing includes a primer that, when struck, ignites the gun powder. The pressure built by the burning gun powder increases rapidly and forces the projectile to leave the casing and travel down range.) By loading each bullet on site, the range can control the amount of gun powder placed in the casing to ensure that the projectile strikes the armor at the desired velocity. These velocities are also specified by NIJ Standard 0108.01. In the case of the 44 Magnum, the striking velocity must be between 1350 feet per second and 1450 feet per second. For an impact to be considered fair, it must be with the specified threat, at the specified velocity, and within ½” of the intended impact location.
To meet NIJ Standard 0108.01, testing must be performed at a certified independent test laboratory. There are several around the country, including HP White, Chesapeake Testing, and Oregon Ballistic Laboratories. These test facilities provide impartial test data that is consistent and independent of the armor solution itself. All armor is shot in the same way using consistent projectiles by trained personnel. Our testing was performed at Chesapeake Testing.
Reading a ballistic test report for the first time can be confusing. There are several important pieces of information that you should look for. The first is the panel size or description. This lets you know if the test panel is similar in size to the product. The next important information is contained in the data table. Each table will specify at least two velocities as the projectile velocity is measured twice for each test. Some reports will also specify an average velocity, which is just the arithmetic average of the two measured velocities. This average velocity is considered the impact velocity, and this is the value that must be between 1350 and 1450 feet per second for an NIJ Standard 0108.01 Type III-A solution being tested with the 44 Magnum. Lastly, it will have a column that states “Penetration” or “Result”. If the value in this column is None, the bullet was stopped (this is sometimes also referred to as a partial penetration, PP, or P). If the value in this column is Bullet/Spall, the bullet was not stopped (this is sometimes also referred to as a complete penetration, CP, or C). For testing in air, a 0.02” thick 2024-T3 aluminum sheet is placed 6” behind the armor. (This thickness and type of aluminum has been determined to simulate human flesh.) After each impact, the aluminum sheet is inspected. If light can be seen coming through the aluminum sheet after an impact, the impact is determined to be a complete penetration. If no light is visible, the impact is determined to be a partial penetration. (There are times when a portion of the projectile finds its way through the armor and impacts the aluminum sheet without creating a hole. This is still considered a partial penetration.)
Additional information contained in the test report can also include the weight of the projectile (in grains), range information (temperature, humidity, location of the velocity measuring devices, location of the barrel), date and time, and Obliquity of the projectile relative to the target. Obliquity relates to the direction the projectile is traveling relative to the target. For NIJ Standard 0108.01 testing, we want the projectile to be traveling perpendicular to the target. This equates to an obliquity of 0 degrees. To be a fair impact, the obliquity must be less than 5 degrees. The test report sometimes also states the time (in micro-seconds) that the projectile took to fly between the measuring devices that calculate the velocity (there are four measuring devices total). To calculate the velocity, you divide the distance (in feet) by the time reported in seconds. So, if the measuring devices are three feet apart and the projectile took 2152 micro-seconds to travel from one device to the other (0.002152 seconds), the calculated velocity is 1394 feet per second.
One additional part to understand about product performance relates back to statistics. Obviously, the performance of the product depends highly on both the projectile and the product. Each projectile has minor differences that can make it easier or harder to stop. In addition, although we attempt to make the product as uniform as possible, there are still variations across the product panel that can improve or degrade performance. We therefore overdesign the product to account for the potential that a harder to stop projectile impacts a spot on the product that has degraded performance. The more impacts the product faces without a penetration, the more confident we are that the product will be able to stop the desired projectile. It is not possible to statistically determine that we are 100% confident that a product will stop 100% of the projectiles. This would require all of the products ever made to be impacted, which would make the armor product unusable.
Although not required by NIJ Standard 0108.01, the product should be impacted multiple times to develop confidence in the solution. The question becomes how many impacts are required to develop confidence that the product solution is robust. After years of testing and analysis, it has been determined by the industry that being 90% confident that the product will stop 90% of the projectiles relates to a very robust product solution. To accomplish this level of confidence, the product must stop 22 projectiles out of 22 impacts. To date, our ballistic shield has been impacted fairly 56 times and has stopped all 56 impacts.
As if all of this testing isn’t enough, there is still additional testing that should be done. In most cases, including ours, the product will not be used as it was tested per the standard. The product should therefore be tested in the manner it will be used – called “as mounted” testing. In our case, the ballistic shield will be held by the handles and will be unsupported around the edges. We therefore developed a test fixture that placed the shield in this position to ensure that the shield would still stop 5 projectiles when held by the handles. A block of wood was placed behind the handles to simulate the support that will be provided by the hands during use. Each shield was impacted 5 times at various locations. Impacts were placed near the handles, on the support structure (that simulated hands), near the center, and near the edges of the panel (within 1” of the edges). The shield successfully stopped all 15 impacts during this testing and the handles remained intact through all 5 impacts (three panels were tested).
The Ohio State University Test Report
The Ohio State University, Armor Protection Ballistic Resistance Test: Job No. 2747-001, Tested 12 September 2019,