By Jeannine Heinecke

Piecing together the construction of soft body armor

hen I started in law today’s soft body armor is becoming “W enforcement in the mid- a more sleek, comfortable, flexible, 1970s, the first vest I got looked life-protecting second skin for law and felt like a Manhattan Yellow enforcement officers. With this evo- Pages wrapped in a plastic bag,” lution comes improved wear rates describes Georg Olsen, a long-time and more lives saved. “Officers aren’t veteran of law enforcement and obstinate or stupid,” comments general manager of U.S. Armor, Olsen. “They want the protection, located in Cerritos, California. but they have to have the flexibility Through the evolution of ballistic and mobility to do their jobs.” fibers and construction methods, Part of finding the right protec- U.S. Armor’s Tactical Assault Vest (T.A.V.) and Terminal Velocity series vest. tion is making an educated deci- Wagner, manager of technology construction allows for faster ener- sion when purchasing soft body for Honeywell’s Advanced Fibers gy dissipation and reduced back- armor. Officers need to know and Composites Group. “It has face deformation — the energy that the types of fibers used, how a an orientation and regularity. The was not dissipated by the vest and vest should properly fit and the order of the molecular chains is will impact the body. advancements in construction aligned along the length of the Honeywell discovered this pro- methods leading to more fiber, which helps with the trans- cess not only works for HPPE comfortable, wearable vests. mission of energy and gives it the fibers but for aramids as well. “The high-strength quality.” concept of aligning and position- Energy’s catcher’s mitt Once aligned on the molecular ing fibers to their ultimate perfor- Soft body armor is designed to level, it is important to maintain this mance level extends into any high- absorb energy — whether from the orientation in the spinning process. impact of a bullet, a vehicle or any “During the spinning process, being other life-threatening source — and able to orient those chains along the “In a soft armor disperse it over a wide area. Fibers length of the fiber is what imparts the product, you can affect are the filaments across which this ballistic performance,” says Wagner. performance by the impact energy is transmitted, and Weaving interlocks the fibers so how those fibers are created and the strength orientation is directed stitching, layering of aligned determines their ability to both vertically and horizontally. materials and use of disperse energy. But at these intersections of fiber, There are two basic types of bal- energy “roadblocks” are created, different materials.” listic fibers used in soft body armor reducing the rate at which energy — Dr. Lori Wagner, Honeywell construction: aramid and high- can be dissipated. performance polyethylene (HPPE) Honeywell, located in Colonial performance fiber that can be used fibers. Honeywell’s Spectra and Heights, Virginia, has developed in ballistics,” she says. DSM’s Dyneema are HPPE fibers, a rolled fabric material, called She also notes the market has while Dupont’s Kevlar and Teijin Spectra Shield, that instead of expanded significantly from the Twaron’s Twaron are aramid fibers. being woven is a laminate. In this early 1990s where monolithic — Whether aramid or HPPE, these process, the fibers are aligned in single fiber type — vests were the fibers have a few common traits. one direction, spread into a web norm. “In the ballistics arena, many They have high strength or tenac- and adhered with a resin. Then two times the two materials (aramid ity (tenacity being a strength per fiber resin sheets are layered — one and HPPE) are combined because weight ratio). They also tend to in a 0-degree direction and the the performance of each adds to have a high modulus or stiffness other in a 90-degree direction — the other synergistically,” explains and low elongation, which provides and fused. “This gives you strength Wagner. “The hybrids come out as for better energy dissipation. in all directions,” says Wagner. “At a benefit because each material adds “The structure of the fiber also the same time, it doesn’t disrupt all its own special component to the imparts some of the high-strength of the orientation we have worked vest. They create a great catcher’s characteristics,” explains Dr. Lori so hard to put in the fiber.” This mitt for energy absorption.” Original vest patterns, at left, are still the basis for the now computerized system. Above, a worker stitches the cover of the ballistic panel.

Building the perfect sandwich manipulate the order and number of which the sandwich is mounted, are With the fibers now woven or lami- layers to achieve the desired effect. the chronograph’s three — start, nated into a rolled fabric product, the In the end, the 21 layers may break stop and proof screens — that manufacturing of a ballistic vest begins down into three Spectra Shield, measure the bullet’s velocity. “The with research, development and the two Gold Flex, seven Kevlar, four difference between Levels IIA, building of a sandwich. Manufacturers Spectra Shield and five Gold Flex. II and IIIA is in bullet speed,” weigh the benefits of aramid — releas- “The layers are put in the order that explains Olsen. “The faster the es body heat and moisture to create accomplishes those functions of bullet, the higher the threat level.” a more comfortable vest — and the stopping and dissipating in micro­ At the front of U.S. Armor’s benefits of HPPE — higher tenacity seconds at impact,” says Olsen. range is the mounting tower which and chemical resistance. Based upon But not all sandwiches are creat- holds a Thompson Contender. U.S. these qualities and the goals for the ed equal. Each threat level requires Armor uses this single-shot hand- product, it is determined if the vest will a different composition and layer- gun because it has interchangeable be produced from a single fiber or a ing. Olson also notes that to reverse barrels and can test for a variety of combination of materials. the sandwich front to back would bullets and calibers. According to Wagner, manufac- create entirely different results, and Once the sample achieves the turers have found that combining may cause the vest to fail. appropriate response — less than materials allows for lighter weights, 44mm of backface deformation a greater range of threat protection, Putting the vest to the test and resistance to rounds with and improved comfort, flexibility and As the composition of the sand- an appropriate speed for the backface deformation performance. wich is being developed, 15-inch threat level in question — a vest- In the research and development by 15-inch sample sandwiches patterned sandwich is cut. “The process, a sandwich is created — a are shot. The shooting range is panel will perform better than the precise layering of ballistic materi- designed such that the bullet trap 15-by-15 sample because there is als to meet the desired threat level. is at the back preceded by a clay more area to disperse the energy, As an example, a sandwich may box. The clay in this box is kept but we want to put it in its worst- have 21 layers — seven Gold Flex, at a specific temperature and used case situation first,” Olsen explains. seven Spectra Shield and seven to measure backface deformation. Because the smaller sample Kevlar. “But not only are the ingre- Guidelines allow for up to 44mm already meets National Institute dients of the sandwich important, of backface deformation, although of Justice (NIJ) requirements, it is equally important at what medical professionals say the body when making the full-size vest, it is order they go in,” explains Olsen. can withstand 70mm to 80mm. inherently overbuilt with a greater In the research process, testers In front of the clay box, on margin of safety. “If you’re build- The Gerber cutting machine operates ing a product that peoples’ lives like a drill slicing through the layers are depending on, would you build of ballistic fiber and client-coded pattern. The CNC machining allows it just to the very edge of perfor- for replicable precision. mance? No,” says Olsen. “By mak- a V50 and get 1,600 fps,” describes ing it more difficult on ourselves Armellino. “I can then cut another when we create the product, we panel from the same roll, test it, end up with a product that has the and get 1,550 fps. There is a devia- overbuild already in it.” tion in brand new material from Once the sandwich achieves the same rolls of fabric.” NIJ-level testing, manufacturers Olsen adds that if 10 vests were then perform a V50 test. In this cut from the same roll, “you would test, the same piece of armor is not get any two to have the same shot by increasingly faster bullets results, but your expectation is that until a round penetrates the vest. they would all be the same,” he Throwing out the fastest and slow- says. “Look at the V50 as an over- est speeds, the remaining speeds view guide, not an absolute.” are averaged to determine the V50 rating. “The V50 will show if a Cutting, sewing, trimming vest is degrading and at what rate,” With the sandwich layering deter- explains Olsen. “You never want it mined and the measurements in hand to go below the speed of the NIJ (see “Weights and measurements on requirement bullet.” Page 86), it’s time to build the vests. Knowing the V50 rating on a Vests of the same polymer com- new vest allows departments to position are grouped together and take vests that have been used in constructed at the same time. This the field for two, three or more may include orders from a depart- years and compare the V50 rat- ment outfitting all its officers with ings. Olsen describes the V50 as the same vest or individual orders are recycled. They are ground into an “early warning system” to how that have accumulated over time. a course powder and converted quickly vests are degrading, which Each officer’s measurements are into clutch plates and brake shoes. may lead departments to update inputted into a computer, which then A technician then rolls the layers replacement timelines. lays out the patterns for each vest of ballistic fiber onto the cutting table Stephen Armellino, president component to maximize fabric effi- in the order developed during the of U.S. Armor, cautions that just ciency. Because of the cost of materi- research process. Once this layering is because a product brochure lists a als, “You don’t want to be wasting a complete, the pattern sheet is placed specific V50 rating not every vest lot of material,” notes Olsen. on top. The Gerber cutting machine is will test to this exact same number. The inevitable scraps of integrated with the software that writes “I can cut one panel of the mate- ballistic material that do accumu- the pattern, and therefore, doesn’t actu- rial as it’s configured and sewn, run late through the production process ally read the pattern sheet rolled across Weights and measurements How a vest fits and feels is just as important as the protection it provides. the ballistic sandwich. But the As Georg Olsen, general manager of U.S. Armor, points out, “The best recom- mendation for body armor happens on the bench in the police locker room or pattern sheet is still used because it in the front seat of a patrol car. An officer lists the corresponding name and is more likely to ask a co-worker what vest he selected and why.” serial number so the custom-fit Comfort is the key guiding factor in vest ends up in the hands of the armor use. If a vest is not comfortable, it appropriate person. will not be worn. If it is not worn, it will not provide the life-saving protection. When custom orders are being When purchasing soft body armor, produced, only one layer of vests officers have two options: standard siz- can be cut at a time. If stock sizes ing and custom measurement. Some officers will comfortably and accurately are being produced, thin sheets fit standard sizes, but most people do of plastic can be rolled between not fit the mold and will benefit from a custom, tailored fit. the ballistic sandwiches so that Standard measurement points when multiple layers of vests can be cut purchasing a vest include around the at the same time. chest, around the waist, front of vest standing, front of vest sitting and length At U.S. Armor, a fan system of back. U.S. Armor includes the “third beneath the Gerber draws air dimension” measurement, measuring down, holding the material in from the top of the belt in the front to the top of the belt in the back. As Olsen points out, “The third dimension is the great equalizer. Human bod- place so it doesn’t slide or move. ies are three dimensional, not two. If they were, this would be simple. We’d A dry run of the cutter is per- just use a pair of scissors and a cardboard cutout.” Although three officers may have the same height and weight, they may formed. The technician watches have different vest needs. One may have a long torso and short legs while that the cutter follows the lines another has a short torso and long legs. If one officer is more rotund, he on the pattern, although at this will have different fit and measurement needs as well. “Females particularly need the third dimension,” notes Olsen. point, just a laser guide indicates Aside from cut, weight is often a determining factor in armor purchases. where the cut will take place — Olsen warns that the weights printed on promotional brochures often can the blade is not yet in motion. be deceiving. If a department chooses to consider the weight, they should consult the National Institute of Justice test results. With these reports, all After a successful dry run, vests from all manufacturers are being weighed at the same location and by the pieces are cut. “The blade the same people. Using U.S. Armor’s own products as an example, Olsen brings to light actually operates more like a the difference in weights between the Enforcer Terminal Velocity and the drill,” notes Olsen. The CNC Enforcer XLT. Although the XLT weighs slightly more than the Terminal machining allows for repli- Velocity (a difference of 0.29 ounces ballistic weight per square foot at Level IIA protection), to feel the two vests in hand and on the body, an cable precision. officer would assume the XLT were the lighter vest. As the pieces are excised “Comfort and wearability have much less to do with weight than base materials used and methodology in the construction of those materials,” from the fabric, the technician says Olsen. stacks them, making sure to Because of this, Olsen recommends all departments conduct a wear test keep the paper pattern with before purchasing. Departments should select a couple officers — including a female officer and the officer known to complain the most or the harshest the ballistic sandwich, ballistic critic — to wear various vests for a couple weeks at a time. Manufacturers cover or outside carrier — should be willing to supply vests for this test period. whichever of the three compo- “How the vest fits and wears, how the officer feels about it, and whether he feels comfortable wearing it and inclined to wear it, all come into play nents is being produced. when purchasing vests,” says Olsen. Proper protection Determining the appropriate threat level of soft body armor to wear on patrol is not so much dictated by National Institute of Justice (NIJ) recommendations but by the daily threats on an officer’s beat. The NIJ recommends Level IIA for day-to-day wear, but this may not be sufficient depending on what the criminals in the area are carrying or even what the standard duty handgun is. “You want to key what you are wearing to what you are carrying,” recommends Georg Olsen, a for- These hybrid ballistic sandwiches, composed of Spectra Shield, Gold Flex mer law enforcement officer and and Kevlar, are tacked in specific areas general manager of U.S. Armor. before being enclosed in their covers. “More than 10 percent of police officers are shot with their own weapons or friendly fire, so you and carrier match. “They are check- need to stop at least what your agency is carrying.” Following cutting, the pieces are ing when they are assembling, cut- What the criminals on the moved to the sewing line. “Different ting, cleaning, packing, all through- street are packing varies greatly pieces of armor are stitched in dif- out the process,” reiterates Olsen. depending on location. Olsen recommends an easy, quick test ferent ways,” notes Olsen. Vests may Now ready for boxing, the that helps determine this threat. just have a few lines of sewing to vests are placed in a plastic bag “Ask yourself, what were the guns I took off the last 10 guys I arrest- keep the layers of material together, with an information sheet and a ed?” he says. Because the crimi- while the ballistics in a breaching copy of the original order. nal’s primary source of obtaining blanket are quilted. But the story does not end with weaponry is robbery, he is getting bigger caliber and better weapons. “You can affect ballistic perfor- the vest in the box. It continues Olsen notes the .380 automatic mance by the way you construct the today with further research and that once topped the list of crimi- nal weapons, and is resistant to a vest,” adds Wagner. “In a soft armor development and an ongoing effort Level IIA vest, has quickly been product, you can affect performance to increase wear rates. “Innovation replaced by the 9mm. by the stitching, layering of materials is still happening,” promises Wagner. Therefore, as a manufacturer, U.S. Armor recommends officers and use of different materials.” “There is a constant drive to devel- wear Level IIIA. The protection Each vest is marked with its op lighter weight, more comfortable range granted by the Level IIIA far appropriate sewing lines. The bal- solutions to protect officers against surpasses the weight difference between the IIA and IIIA. “You’re listic sandwich is then sewn into its all threats. And there is a lot of talking about a weight difference cover, and the carrier is also sewn. technology still left out there to be between the Level IIA and Level IIIA of half a pound per square At the assembly stage, any loose able to achieve that.” foot — less than 2 pounds over threads are trimmed — both inside Long gone are the days of the the entire vest,” says Olsen. “The and outside the carrier and vest. phone book strapped to an offi- weight is more psychological than anything else. It’s really all about Once again, the serial numbers are cer’s chest. Tomorrow’s soft armor the officer’s perception of fit, checked to be sure that both the vest vest may truly be a second skin. ■ comfort and flexibility. ”

Reprinted with permission from Law Enforcement Technology magazine • June 2007