Slash-resistant clothing can reduce the risk of knife injuries and lacerations, keeping frontline professionals safer.
By Robert Kaiser
Throughout history, people have protected themselves with specially designed and constructed garments. From furs and chain mail to leather, metals and high-tech fabric, human beings have creatively employed a range of materials to protect against injury and death.
Cut-resistant fabrics have been on the market for some time; however, these materials are not as effective against slashing. With the evolution of specially engineered fabrics, the wearers of newer options in slash-resistant clothing—such as law enforcement officers, prison guards, private security personnel and counterterrorism professionals—are offered dexterity as well as a high level of protection against very specific threats.
Slashing has become an occupational hazard for many public-facing professionals. Assaults may be perpetrated by highly trained individuals who purposefully attack a vulnerable area to incapacitate the target; in other cases, a victim may be accidentally slashed in a frenzied attack. The key function of slash-resistant clothing is to reduce the risk of lacerations and protect key arteries—keeping the wearer of the protective clothing fully operational and unharmed.
Knives, blades and spikes
All personal protective equipment (PPE) is designed to protect against specific risks. For example, vests made from stab-resistant materials offer protection from an individual using a knife, blade or shank. Only a few stab-resistant vests or materials offer spike protection. A spike is almost like a big nail; creating spike protection is the greatest challenge for fabricators in this market segment. Because a spike is extremely pointed, once it pierces the material by a tenth of an inch, the spike can be pushed fully through the material, as the spike does not expand in width over its length. Knitted or woven materials will struggle to offer spike protection simply because a spike would eventually find its way through such material. Usually, ultrathin layers of polycarbonate or aluminum are used to add spike protection.
Slash-resistant clothing is a reasonably new development in the world of PPE. Recent research has established that the majority of knife or stabbing attacks result in slash injuries due to the motion and body movement of the attacker and victim. Highly technical slash-resistant clothing significantly improves personal safety by offering cut protection to areas where body armor and other types of PPE leave the body exposed and vulnerable.
Protecting key areas
Researching and developing slash-resistant protective clothing requires an understanding of human anatomy to protect arteries and major blood vessels.
The side of the neck and throat. This area contains the carotid artery and jugular vein. If either is cut, the victim will bleed to death rapidly. A horizontal cut across the neck will also cut the trachea and ligaments that control movement of the head.
The arms. A deep enough slash to the inside of the forearm between the radius and ulna bones will sever the radial artery. This can result in unconsciousness in 30 seconds and death in as little as two minutes. The brachial artery is deep, but severing it will result in unconsciousness in as little as 15 seconds and death in as little as 90 seconds. Tendons pass through the wrist and are attached to the fingers. If an attacker were to cut those tendons or the muscles that power them, the victim’s hands will no longer be able to close or hold anything.
The legs. Besides the femoral artery, there is an extremely vulnerable area just above the knee, where the muscles in the legs narrow and connect to the patellar tendon. An attacker who is close may reach the quadriceps, making the victim unable to defend himself or herself.
Beyond a personal attack, there are other scenarios that pose dangers. When officers enter a building, they may have to maneuver over broken glass and either climb over or swing through window or door frames. If the vulnerable areas of the body are not protected, the risk of severing an artery is real.
In March 2019, the U.K. edition of The Guardian featured the headline “Police shoot man after officer slashed with knife.” Unfortunately, this was hardly an isolated incident. More recently a global headline read, “Japan knife attack kills 2, injures 16 others at bus stop.” Emergency services and first responders were at risk when engaging with this situation.
Colin Mackinnon, a retired counterterrorist police officer and technical lead for PPSS Group, a U.K.-based producer of high-
performance PPE, was himself the victim of a knife attack. “The offender, who had martial arts training, attacked me with a concealed knife,” Mackinnon says. “Even with training, in the heat of the moment they used a slashing motion rather than a stabbing motion, resulting in four deep cuts to the front of my stab vest before they were overpowered.”
Ian Horsfall and Mathew Arnold of the Impact and Armour Group within the Department of Engineering and Applied Science at Cranfield University (Defence Academy of the United Kingdom) wrote a comprehensive piece on slash knife attacks. A statement from this article reads: “A retrospective survey of hospital admissions data . . . suggested that 63 percent of wounds attributable to sharp-edged weapons were slash events.”
Tests and standards
In the past, most clients and customers had only a limited understanding of cut-resistance performances. To help those individuals, many cut-resistant clothing producers use the EN388:2016 standard. The original version of this standard was intended to test and verify the cut protection of industrial gloves (for example, for sheet metal and the flat glass industry), something many consumers were either aware of or able to easily understand. For this reason, even today many cut-resistant clothing producers use this standard on their technical data sheets.
The latest version of this standard tests the material with four performance criteria: 1) abrasion resistance; 2) cut resistance; 3) tear resistance; and 4) puncture resistance. I believe the second performance criteria, cut resistance, to be of great importance. The highest possible level of cut resistance is level 5. The highest level for the other three criteria is level 4.
The ANSI/ISEA 105-2016 Hand Protection Classification is an important U.S. standard addressing the classification and testing of hand protection for specific performance properties related to mechanical protection (that is, cut resistance). It is another great benchmark and reference point for someone wishing to purchase slash-resistant clothing.
The ISO 13997:1999 “Protective clothing—Mechanical properties—Determination of resistance to cutting by sharp objects” is an extremely important test, a real indicator of true cut protection. The test concludes in a precise newton force number, stating clearly the precise level of protection such a material or garment offers.
The future of slash-resistant clothing
Many technical textile engineers and yarn producers around the world are aiming to further improve cut-resistant fabric. The goal everyone shares is to make slash-resistant clothing and other PPE lighter, thinner and more breathable. That journey starts with the raw fibers.
Future yarns will offer a greater weight-to-performance ratio and allow for the production of protective garments that look like any other garment. Right now, too many frontline professionals, such as counterterrorism officers and covert intelligence and surveillance officers, decide not to wear PPE. They make this choice because the PPE is too hot and too cumbersome, and because their lives would be at risk if the PPE makes them easy to identify in covert situations.
Clothing, uniform, workwear and tactical apparel producers have recently started to analyze the performance of yarns and fibers previously available only to the military and aerospace sectors, all with the safety of frontline professionals in mind.
Robert Kaiser is the CEO of U.K.-based PPSS Group, a producer of high-performance PPE. He is also a consultant for several international organizations and has articles published in industry-leading publications in several countries.
Working with fabric designed for cut and slash protection is a challenge. In the early stages of developing Cut-Tex® PRO single-knit fabric for slash-resistant garments, U.K.-based PPSS Group tested different fabric cutting technologies, from circular and straight cutting machines to computer numerical control (CNC) and water jet cutters. Ultimately, the company chose circular or round cutting machines. Originally engineered to produce cut-resistant workwear for flat glass and sheet metal processing facilities, the fabric was extensively field tested in additional environments and is now used across a range of sectors.