Kevlar technology

     As the need for increased safety and security increases in the United States and throughout the world, DuPont continues to develop new technologies and additional Kevlar fiber capacity to address growing needs.

     Used in ballistic applications for more than 35 years, Kevlar is a name that has become synonymous with keeping law enforcement officers safe on the job. Soft body armor made with Kevlar works by catching a bullet in a multilayer web of woven fabrics. The engaged fibers absorb the energy of the impact and disperse it to other fibers in the fabric weave. It's the ability to combine this high strength with light weight that has made the organic fiber (in the aramid family) popular with law enforcement.

     DuPont's latest generation of woven technology, Kevlar XP (which stands for exceptional performance), offers even more bullet-stopping power, while the relatively new Kevlar Correctional addresses the needs of officers who work in correctional institutions and demand anti-spike protection. Both technologies were designed to be lightweight, flexible enough to be concealed under a uniform, and with officer comfort in mind.

     And that's important, because as Mark McGonagle, global marketing manager for DuPont Advanced Fiber Systems, reminds, the only vest that never works is the one that's never worn.

     Announced this summer, Kevlar XP is initially being made for body armor, but will be used in more ballistic applications and other products in the future. Kevlar XP provides exceptional performance with its ability to consistently stop bullets in just the first three out of 11 layers against the .44 Mag bullet of NIJ Level IIIA, according to tests by DuPont and an independent third-party. The remaining eight layers of Kevlar XP absorb bullet energy, so the vest wearer experiences less trauma, or backface deformation.

     "Backface deformation can have a significant impact on how quickly a police officer can react to the threat he faces," McGonagle says. "If an officer is able to get back up again more quickly, he's more able to defend himself from further attack. Not to mention, less trauma is less painful."

     Kevlar XP typically provides a 15 percent or more reduction in backface deformation. At the same time, it is up to 10 percent lighter than other commercially available technologies designed to defeat a .44 Magnum bullet, the most challenging National Institute of Justice (NIJ) Level IIIA threat.

     In addition, Kevlar XP provides superior layer-to-layer abrasion resistance compared to other ballistic material used in the market today, McGonagle says.

     Finally, in keeping with more rigorous NIJ testing, after exposure to the conditions of heat, humidity and mechanical wear, Kevlar XP is designed to maintain its performance.

     Body armor manufacturers are currently evaluating Kevlar XP. Officers could see Kevlar XP in commercial vests by December.

     Corrections officers require a solution that differs from traditional body armor like Kevlar XP because they typically face different threats on the job than police officers walking the beat.

     The recent death of Federal Correctional Officer Jose Rivera, 22, publicized by the American Federation of Government Employees, drew national attention to the need for correctional officers to wear vests. A Navy veteran, Rivera was killed on June 20 by inmates with handmade shanks at the U.S. Penitentiary in Atwater, California.

     Shanks and knives require different protection technologies than bullets. For example, the tip of a spike is about 100 microns. It's very, very small compared to a deformed bullet that's 1/4 inch. Looking at the measurable ability of a spike to impact a target divided by the contact area at the tip will show that a spike has about 100 more joules per square centimeter than a bullet, says Minshon Chiou, research fellow for DuPont Advanced Fiber Systems. He gives an example of a man able to lie on 1,000 nails without injury but unable to lie on one nail without fearing serious injury or death. When looking only at the energy concentration at the tip, one nail is more difficult to stop than a bullet.

     A knife is another story. It has a cutting edge — in addition to a pointed tip — and is completely different from a spike or bullet.

     "Unfortunately, there's little synergy," Chiou says. "When you try to have one vest provide all the protection an officer needs, the weight just adds up."

     It's a challenge in research and development, yet multi-threat solutions are possible. One Kevlar ballistic material can be combined with another to defeat more than one threat, and DuPont does this in its Kevlar Correctional, which provides protection from bullets, shanks, awls, spikes and handmade knives. When a weapon made to stab an officer strikes the 200-denier Kevlar Correctional material, the fibers dissipate the energy and restrict the weapon from pushing the fibers apart. The technology helps vests meet NIJ Standard 0115.00.

     Chiou predicts different threats will continue to evolve.

     Looking back to the 1980s, there was a different type of threat, which is addressed in NIJ Level I, Chiou says, noting today the .22-caliber is almost obsolete at the street level. Last year, he points out about 50 percent of NIJ vest purchases were Level IIIA.

     "People are looking for a higher level of protection, Chiou says, "and we can anticipate the same in the future." He adds, "people are also looking for multiple threat protection. That means a vest must not only be able to protect against a bullet, it must also protect against knives and spikes, as well as chem/bio hazards."

     More and more, DuPont is addressing the safety of police officers in broader terms. DuPont is in a unique position to protect first responders from thermal, chemical and biological threats with its Nomex, Tychem and Tyvek brands. The rigid molecular structure of Kevlar Correctional offers thermal stability and high resistance to many dangers, including thermal hazards more than 500 degrees Fahrenheit.

     Chiou envisions that in the future, ballistic vests will have smarter fibers to help regulate body temperatures so a police officer working in Texas' summer heat, for example, will be able to comfortably wear a vest for an entire shift. A system of sensors could be incorporated to communicate his vital signs, he adds.

     As technology advances, McGonagle says body armor will become even lighter, more flexible and more comfortable. "If vests are comfortable, people will wear them," he says.

     To meet the growing demand for Kevlar fiber, DuPont will invest $500 million in a multi-phase Kevlar production expansion, which will be finished in 2010. Through fiber development architecture (the art of fiber assembly), DuPont will make its high performance Kevlar an even better performer.

     As different threats (bullets, knives, spikes, military fragments) require different solutions, they are defeated by a different balance of properties, including fiber strength and elongation. Yet, McGonagle says, "We find it's impossible to work only on fiber development. You have to work on architecture development as well."

     Architecture is the structure in which the fiber is placed to allow it to do its job, he describes. Fiber alone cannot stop a bullet or knife.

     Chiou compares fibers to bricks used to build houses. "We are able to make a different type of brick by modifying the fine structure of the Kevlar fiber," he says. But the architecture, or how the fibers are assembled, is important too. Taking the weight out of ballistic solutions also can allow weight to be included for other protection elements, he adds.

     McGonagle points out road traffic accidents have been causing more police officer fatalities than shootings. This happens, in part, because of better ballistic vest technology and increased wear.

     Unfortunately, vest wear rates are not 100 percent, he says. DuPont continues working with the International Association of Chiefs of Police (IACP) to promote vest wear. In 1987, the IACP/DuPont Kevlar Survivors' Club was formed. Since then, more than 3,000 individuals working in law enforcement have survived ballistic and non-ballistic incidents because they were wearing body armor. (For more information, see www2.dupont.com.)

     "We don't ask what material was used in a vest," McGonagle says. "Our goal is to work collaboratively with IACP so that more officers wear their vests. Promotion after lives have been saved by vests really helps. That's peer-to-peer communication — police officers talking to police officers about the importance of wearing their ballistic vest. Vest wear certainly helps. Technology also helps. Police officers will tell you that the more comfortable, lighter-weight vest they have, the more likely they are to wear it. It's a simple matter of comfort and the conditions they have to work in. It's a very active role being a police officer … and the less weight officers must carry and still have the protection, the more likely they are to wear their vest."

     By 2015 DuPont aims to launch 1,000 new products, some of which will include Kevlar and protect the nation's protectors.

     Rebecca Kanable is a freelance writer specializing in law enforcement topics. She lives in Wisconsin and can be reached via e-mail at [email protected].

     The National Institute of Justice's (NIJ's) new performance standard for body armor, NIJ standard-0101.06 (www.ojp.usdoj.gov/nij/pubs-sum/223054.htm), includes more rigorous testing and methods that expose the armor to temperature, humidity, and wear and tear — before performance testing. Performance standards ensure that commercially available body armor provides a minimum level of protection. NIJ has published standards for both ballistic and stab resistance of personal body armor for law enforcement and corrections officers.

     "This important advancement in body armor standards is in direct response to changes in threats faced by law enforcement, advances in ballistic materials and technology, and the need to ensure that body armor performs well when subjected to environmental factors," Associate Attorney General Kevin O'Connor says. "Body armor standards are needed to ensure that law enforcement and corrections officers' equipment provides a high level of safety and protection.

     The new standard is a major component in the Department's 2003 Body Armor Safety Initiative, established in response to concerns from the law enforcement community about the effectiveness of body armor then in use. As part of the initiative, NIJ developed the enhanced compliance testing program in partnership with the National Institute of Standards and Technology, Office of Law Enforcement Standards.

     With the release of this new standard, law enforcement officers do not need to immediately replace the body armor they currently own. NIJ encourages officers to continue to wear body armor listed on NIJ's comprehensive list of models compliant with the NIJ standard. The listing is located on NIJ's Justice Technology Center Network Web site, www.justnet.org/BatPro. NIJ recommends replacing armor when its useful service life has expired with armor that meets the requirements of the new standard.

     More information on the new body armor standard and the U.S. Department of Justice's Body Armor Safety Initiative is available at www.ojp.gov/nij/topics/technology/body-armor/safety-initiative.htm.