New Fabrics Promise Better Fire Protection For IED-Battered Troops
Scientists at the Natick Soldier Research, Development and Engineering Center know that pockets can save lives and that sewing them onto the Army uniform at an angle can curb injury after an explosion by channeling flames away from the face. They understand that the more pockets a uniform has, the more layers of fabric there are between a soldier and fire.
Ever since enemies in Iraq and Afghanistan began using improvised explosive devices, the Army has been on a mission to conquer the threat, which has become the biggest killer of troops in both wars. Much of the focus at Natick is on improving a soldier’s chance of surviving such a blast, and a lot of that has to do with what he’s wearing at the time of an explosion.
Natick engineers recently dressed a mannequin in the current version of the Flame Resistant Army Combat Uniform (FR-ACU) and set it ablaze with a series of blowtorches. The mannequin was outfitted with 123 sensors to capture data about how protected a soldier would be in a sustained fire event, such as being trapped in a burning vehicle following a roadside bomb blast.
The intense fire lasted for four seconds. Then the blowtorches were turned off, and the uniform extinguished itself. The results came back quickly on a computer monitor: The simulated soldier had suffered burns over 29 percent of his body.
Natick scientists regularly conduct tests like this in their quest to find the perfect blend of fabric that no flame can penetrate. The mannequin, which they call Pyro-Man, helps them create a baseline of what protective clothing is available today and what materials may improve a soldier’s chance of survival. And while 29 percent is a drastic improvement over previous uniforms, researchers admit they have a long way to go to reach their goal of preventing all burns.
Easier said than done, says Peggy Auerbach, the lead textile technologist at Natick’s joint Army-Navy thermal test facility, where engineers also have a 650-degree oven and propane burn pit at their disposal.
The Army’s FR-ACU is made from a self-extinguishing fabric that will not melt, drip or be affected by multiple washes. The fabric is called Defender M, a blend of three materials. It consists mostly of flame-resistant rayon and smaller percentages of an anti-ballistic material Twaron and nylon.
The Army began giving these uniforms to deploying soldiers in 2010. About the same time it began fielding the FR-ACU, the service embarked on a project to improve it. Companies sent in more than 52 fabrics for study. The Army tested their resistance to tearing, abrasion and flames in the lab. Pyro-Man single-handedly eliminated some materials from the competition. Other fabrics fought off flames successfully but were not breathable enough, says Maj. Joel Dillon, assistant product manager for soldier clothing and individual equipment.
“We can’t have a soldier wearing a garbage bag,” he says.
Eight fabrics were sewn into full uniforms and given to 300 soldiers at Fort Bliss, Texas, to wear and evaluate. The Marine Corps also tested some of the materials.
The Army went into this effort with the goal of finding a family of textiles they could use in the uniform. But as testing neared completion, only one fabric met all of the criteria — the same blend of rayon, Twaron and nylon called Defender M. The material is produced by a Georgia-based subsidiary of TenCate, which is headquartered in the Netherlands. The only difference between the blend currently in use and the new one is that the threads are larger in diameter.
Test results indicate that this change has worked.
The current uniform has a “burn prediction” just under 30 percent as confirmed by the Pyro-Man test. The new blend brings that down to less than 20 percent, Dillon says. While it could be a few years before soldiers are wearing the improved Defender M, these developments represent dramatic advances for troops, who first began deploying to Iraq and Afghanistan wearing a more flammable mix of cotton and nylon.
Soldiers stateside wear this blend, but it wasn’t helping troops who were trapped in burning vehicles after IED explosions. The flame-resistant uniform is like a second body armor, Dillon says. He notes that it also repels biting insects.
“Since the beginning of the wars in Iraq and Afghanistan, we’ve made huge leaps forward,” Dillon says, and the uniform is constantly being tweaked.
The scientists, testers and designers at Natick constantly seek the input of outside experts in academia and industry. The center just issued a Broad Agency Announcement that covers everything from modeling and simulation to flame and thermal protection. Natick will accept concept papers and proposals up through spring 2013 under the BAA, which seeks to learn about low-cost materials that could protect against fire, as well as new test methods and burn prediction models.
Researchers have been using Pyro-Man for about two years. Natick is one of just four facilities in North America that runs such a test. Right down the hallway from the blowtorches, engineers have a 2,500-watt carbon-dioxide laser that they use to simulate high-heat IED events. Whereas setting fire to the mannequin aims to recreate a sustained fire, the laser represents the flash that would occur the moment an IED explodes. Testers fire the laser, which generates five times the heat of the blowtorches, at patch-sized swatches of fabric to see how they perform.
Precise mathematical models increase the ability to determine how well a uniform will protect a soldier. Natick works with the medical community to increase the accuracy of its models by studying skin thickness and other factors. It’s about location as much as it is about numbers. Depending on where it is, a smaller burn may be worse than what the percentages say is a more severe injury.
“Normally the goal is to reduce the overall percentage of body burn,” Auerbach says. “But it matters where the burn is. If you have 5 percent burn in your hands, you could be completely disabled. Whereas if you have 20 percent and it’s all on your back, you might not want to go out on the beach but you could still function.”
Researchers receive data from the field constantly, so they know where soldiers are suffering the worst burns. Officials are currently conducting a study on the impact the flame-resistant uniform has had on injuries in theater.
There is always concern about the hands and face, which the uniform does not cover. The Army has a lightweight hood that soldiers can wear over their faces. It is knit and consists of polybenzimidazole (PBI) fibers that are also used in firefighting gear. While a great guard against flames, PBI isn’t used with the main uniform because it is extremely difficult to imprint with camouflage colors, Dillon says. Troops also have flame-resistant gloves, shirts, pants and coveralls.
There are a multitude of technologies that can be used to shield a soldier from fire. There are already products — including face paints — that could do a formidable job if all were used at once, but that is impossible, Auerbach says.
“You could come up with a great system to protect the soldier but if you’re not going to wear it, it’s no good,” she says. “We can’t encapsulate [a soldier] in something he’s not going to wear. There’s always this balance between comfort, weight and protection. There are always trade-offs.”
The military has looked for new materials high and low. The Pentagon has been working with the sheep industry for some time and, as the largest consumer of domestic wool, buys more than 6 million pounds each year for dress uniforms. This is more than double the amount of wool the military used in its uniforms just a few a years ago. These numbers probably will continue to increase as the Defense Department investigates the use of wool in flame-resistant clothing.
“When you think about wool, you automatically think scratchy and heavy and hot,” Dillon says, “but it doesn’t have to be that way.”
Super-washed wool has been used to make lightweight t-shirts, he says. This type of wool undergoes special treatment processes to remove scales from the fiber. This can be done by using an acid bath or coating the material with a polymer that seals the scales.
One of the impediments to providing washable wool to the military has been the Berry Amendment, a law that requires the Pentagon to buy materials completely produced in the United States. Most of the wool previously had been treated outside of the country, but efforts are under way to turn this around.
The Sheep Venture Co., a for-profit enterprise owned by the American Sheep Industry Association, late last year struck a deal that brings super-wash equipment to the United States. This development will help fill a void that has hampered processing on the home front for some time and limited the use of wool in military products.
Proponents say that U.S. wool is fire resistant and has antimicrobial properties that make it easy to care for when soldiers don’t have access to washing machines. The Army didn’t consider wool as one of the 52 fabrics for the new flame-resistant uniform, but industry representatives say its use in military clothing is bound to increase.
The Sheep Venture Co. has studied wool treatments for the Army and has proposed to develop new fire-resistant products. The Army’s Program Executive Office Soldier also is working with contractors to field FREE, the fire-resistant environmental ensemble, aimed at providing protection to soldiers in the confined spaces of helicopters and armored vehicles. The ensemble consists of 17 individual components, some of which contain wool.
American Sheep Industry military consultant Mitch Driggers estimates that 2 million sets of FREE will be produced requiring more than 1 million pounds of domestic wool. This program marks the first time since the Korean War that wool has been included in new U.S. military garments, and the trend will continue, Driggers says.
Wool is self-extinguishing and can carry a third of its weight in water within its fibers without getting wet. It also adds comfort when blended with synthetic fibers that are already flame-resistant, says Driggers, a retired Air Force major who previously oversaw clothing programs for the Pentagon.
The FREE system uses wool in conjunction with Dupont’s Nomex fiber, rayon, nylon, Lycra and spandex. But the sheep industry would like to see it incorporated into the FR-ACU.
“Wool truly is a miracle fiber,” Driggers says. “It is the most versatile fiber in the world. It’s kind of like the Swiss Army knife. It does a lot of things very well.”
Topics: Land Forces