Grunt (2 page)

It’s a balmy 68 degrees at Natick this afternoon. It may, at the same time, be 70 below zero with horizontally blown snow or 110 in the shade, depending on what’s being tested over in the Doriot. The Doriot Climatic Chambers were the centerpiece of the complex when it opened in 1954. Never again would troops be sent to the Aleutian Islands with seeping, uninsulated boots or to equatorial jungles with no mildew-proofing on their tents. Soldiers fight on their stomachs, but also on their toes and fingers and a decent night’s sleep.

These days, the snow and rain machines are rented out to L.L. Bean or Cabela’s as often as they’re used to test military outerwear. Repelling the elements is the least of what the US Army needs its uniforms to do. If possible, the army would like to dress its men and women in uniforms that protect them against all that modern warfare has to throw at them: flames, explosives, bullets, lasers, bomb-blasted dirt, blister agents, anthrax, sand fleas. They would like these same uniforms to keep soldiers cool and dry in extreme heat, to stand up to the ruthless rigors of the Army field laundry, to feel good against the skin, to look smart, and to come in under budget. It might be easier to resolve the conflicts in the Middle East.

L
ET US
begin at Building 110, which is what everyone calls it. Officially it was christened the Ouellette
†
Thermal Test Facility, lending a flirtatious French flair to lethal explosions and disfiguring burns. The head textile technologist is a slim, classy, fiftyish woman of fine-grained good looks, dressed today in a cream-colored cable-knit wool tunic. I took her to be the Ouellette, and then she opened her mouth to speak and a hammered-flat Boston accent flew out and slammed into my ear. She is an Auerbach, Margaret Auerbach, but around 110 she’s just Peggy, or “flame goddess.”

When someone in industry thinks they’ve built a better flame-resistant fabric, a sample comes to Auerbach for testing. Some people submit swatches; others optimistically ship off whole bolts. Their hopes may be undone by a single strand of thread. “To see what our guys might be inhaling,” Auerbach heats a few centimeters of thread to around 1500 degrees Fahrenheit. The fumes produced by this are identified by gas chromatography. Flame-resistant textiles—some, anyway—work via heat-released chemicals. Auerbach needs to be sure the chemicals aren’t more dangerous than the flames themselves.

Once it’s established that the textile is nontoxic, Auerbach sets about testing its flame-stopping mettle. This is done in part with a Big Scary Laser (as the sticker on its side reads). Auerbach places a swatch in the laser’s sights. And here is the best part: To activate this laser, you push a
giant red button
. The beam is calibrated to deliver a scaled-down burst of energy representative of an insurgent’s bomb—a teacup IED. A sensor behind the swatch measures the heat passing through, yielding a figure for how much protection the fabric provides and what degree burn would result.

Auerbach switches on a vacuum pump that sucks the swatch tight against the sensor. This is done to approximate an explosion’s pressure wave—the dense pileup of accelerated air that can knock a person flat. More subtly, it forces clothing flush against the skin, which can heighten the heat transfer and worsen the burn. One of the winning attributes of Defender M, the textile of the current Flame Resistant Army Combat Uniform, or FR ACU (“the guys call it ‘frack you’”), is that it balloons away from the body as it burns.

The downside to Defender M has been that it tears easily. (They’re working on this.) The same thing that keeps it comfortable in hot weather also makes it weaker; it’s mostly rayon, which draws moisture but has low “wet strength.” If a garment tears open in the chaos of an explosion, now the protective thermal barrier is gone. Now you’re toast. The manufacturer throws a little Kevlar in, but it still isn’t as strong as Nomex, a fiber often used for firefighter uniforms. Nomex also has superior flame resistance: It buys you at least five seconds before your clothes ignite.

Auerbach explains that this is especially important for crews inside tanks and aircraft. “Where they can’t roll, drop, and . . .” She rewinds. “Drop, stop . . . what is it?”

“Stop, drop, and roll?”

“Thank you.”

Why not make all army uniforms out of Nomex? Poor moisture management. Not the best choice for troops running around sweating in the Middle East. And Nomex is expensive. And difficult to print with camouflage.

This is how it goes with protective textiles: Everything is a trade-off. Everything is a
problem.
Even the color. Darker colors reflect less heat; they absorb and transfer more of it to the skin. Auerbach goes across the lab to get a swatch of camouflage print cloth. She points to a black area. “You can see this has a pucker where it was absorbing more heat.”

“It has a what?” I heard her, but I need to hear her say
pucka
again. The fabulous Boston accent.

I would have guessed the military to be a fan of polyester: strong, cheap, doesn’t ignite. The problem is that it melts and, like wax and other melted items, it drips and sticks to nearby surfaces, thereby prolonging the contact time and worsening the burn. What you really don’t want to be wearing inside a burning army tank is polyester tights.
‡

To determine what degree of injury the heat would produce, Auerbach runs the reading from the sensor behind the cloth through a burn prediction model—in this case, one developed after World War II by original flame goddess Alice Stoll. Stoll did burn research for the Navy. To work out first- and second-degree burn models, she gamely volunteered the skin of her own forearm. You may excuse her for letting someone else help out with the third-degree burn curve. Anesthetized animals were recruited for this—rats, mostly, and pigs. Pig skin reflects and absorbs heat in a manner more like our own than that of any other commonly available animal. The pig as a species deserves a Purple Heart, or maybe Pink.

What Stoll learned: When flesh reaches 111 degrees Fahrenheit, it starts to burn. The Stoll burn prediction model is a sort of mathematical meat thermometer. The heat of the meat and how deeply into the skin that heat penetrates are the critical factors that determine the degree of the burn. A brief exposure to flame or high heat cooks, if anything, just the outer layer, creating a first-degree burn or, to continue our culinary analogy, lightly seared ahi tuna. A longer exposure to the same heat cooks the inner layers, too. Now you have a second- or third-degree burn, or a medium-rare steak.

Even without a flame, clothing can catch fire. The auto-ignition temperature for cotton, for instance, is around 700 degrees Fahrenheit. Exposure time is key. The heat pulse from a nuclear blast is extremely hot, but it’s traveling at the speed of light. Might it pass too quickly to ignite a man’s uniform? Natick’s early precursor, Quartermaster Research and Development, actually looked into this.

Operation Upshot-Knothole was a series of eleven experimental nuclear detonations at the Nevada Proving Grounds in the 1950s. The Upshot-Knothole scientists were mainly interested in the blastworthiness of building materials and tanks and bomb shelters, but they agreed to let the uniform guys truck over some pigs. Anesthetized Chester White swine, 111 in total, were outfitted in specially designed animal “ensembles” sewn from different fabric combinations—some flame-resistant and some not—and secured at increasing intervals from the blast.

Flame-resistant cool-weather uniforms with a layer of wool outperformed a series of thinner flame-resistant hot-weather uniforms—whose developers had surely, by “hot weather,” not had in mind the extreme swelter of nuclear blast. The researchers marveled to note “a complete lack of any qualitative evidence of thermal injury to the fabric-protected skin of animals dead on recovery at the [1,850-foot] station.” I don’t wish to be an upshot-knothole, but who worries about burns on subjects close enough to a nuclear explosion that they are, as the report succinctly terms it, “blown apart”? Despite the clanging absurdity of the scenario, it was a memorable demonstration of the importance of exposure time. With the fast-traveling heat from a bomb—including a more survivable one like an IED—a few seconds of flame resistance can make all the difference.

The wool helped, too, because hair is naturally flame-resistant. Natick has, of late, been looking into a return to natural fibers like silk and wool. Not only is wool flame-resistant and nonmelting, it wicks moisture away from the body. Auerbach says she has seen some very nice, soft, flame-resistant cool-weather sheep’s wool underwear. The hairs have to be descaled so the wool isn’t itchy, and the garments need to be treated to keep them from shrinking, and both these processes add to the cost. As does the Berry Amendment, which gives preference to domestic suppliers of military gear. The Berry is additionally problematic in this case in that—despite the breathless, eager assurances of the American Sheep Farmer’s Industry—there may not be enough sheep in all of America to fill the bill.

So let’s say your new textile is comfortable and affordable. The flame resistance plays well with the insect-repellent treatment and the antimicrobial stink-proofing. Now what? Now you bring some over to the Textile Performance Testing Facility. You run it through the Nu-Martindale Abrasion and Pilling Tester to get a feel for how quickly the treatments will succumb to soldierly abuse. You subject it to a couple dozen wash and dry cycles. Laundering removes not only grime but also, bit by bit, the chemicals with which a cloth or fiber has been treated. When I visited the textile testing facility, a man named Steve was waiting for some pants to get through an accelerated wash. One wash in the Launder-Ometer equals five normal washes, he told me.

“That’s something,” I said.

“Yup.” He stuck out his lower lip in a contemplative way. “Steel balls bang against the fabric.”

If only the minds of Natick could invent a fabric that didn’t need laundering. If everything splashed, smeared, or spilled on a uniform just beaded up and rolled off, if uniforms could be cleaned with a quick spray of water, think how much longer they’d last. And how much safer they’d be in the event chemical weapons rained down on them.

The minds of Natick are on it. Over in the liquid repellency evaluation lab, they’re putting to the test a new “super-shedding” fabric treatment technology. Escorting me to a demo will be Natick’s calm, likable public affairs officer, David Accetta. We meet up in his office, one side of which is piled with boxes from a recent move. A wall calendar features dog breeds. September is a large white poodle. Accetta was most recently deployed to Bagram Airfield in Afghanistan, where he spent his days writing press releases about the Army’s humanitarian efforts. His superiors would ask him why the stories rarely got any play. “They didn’t get it. It’s not news.” He relates this with no trace of anger. There are many irritating things about Accetta’s job, but he never sounds irritated. He takes everything in stride, which is a bad cliché to use for him, because he’s not a striding sort of guy. He’s more of a moseyer. He has long eyelashes and a slow way of blinking. I almost wrote
doll-like
there, but the adjective seems out of place with the rest of Accetta’s face, which is crossed by a thin, rakish scar that begins at one temple and curves down and around his cheek. I don’t ask about it, preferring to supply my own made-up narrative of flashing sabers and staircase choreography.

We are early, so we take a walk along Lake Cochituate, which forms a property line for part of the Natick grounds. Sunlight is scattered on a low chop. Water from the lake, a deep blue-green in today’s light, was at one time used to make Black Label lager. Natick activities pretty much put a stop to that. For a Superfund site, the grounds are quite pretty, with gazebos and meandering footpaths. Cylindrical gray-white Canada goose droppings add to the parklike atmosphere. It took a while to realize what these were, because I didn’t see any geese. It’s fall. Maybe they just flew south.

Accetta and I stop to watch an officer addressing a group of HRVs: human research volunteers—arms and feet and heads to go inside the parkas and boots and helmets. They are soldiers deployed to taste rations, sleep in new sleeping bags: test, report back, test something else. A temporary duty assignment at Natick is not necessarily a soft gig. I saw a photograph, from the sixties, of a group of soldiers in raincoats and waterproof pants, heads bent, hoods dripping, walking in circles under a simulated downpour. Apparently this went on for hours.

The volunteers, ten or so, stand in a row in the parking lot outside their barracks. A car backs out of a parking slot behind them. The soldiers take three steps forward, in formation, and one step up, onto the curb. When the car pulls away, they step backward and down. Anytime they walk someplace in a group of four or more, Accetta says, they have to be in formation. Like geese flying south.

T
HE DEMONSTRATION
begins with the farting sound of a squeezable mustard bottle. A line of glistening yellow joins the duns and drab olives of a square of camouflage fabric. The cloth is clipped to a sloping board to foster roll-off. This being a roll-off test. As a cameraman and a small crowd look on, the line of mustard creeps down the cloth, holding its shape perfectly. A young chemical engineer, Natalie Pomerantz, directs onlookers’ attention to the terrain across which the condiment has just traveled. “No residue trail!”

Ketchup follows, then coffee, and milk, as though the owner of the uniform had engaged the enemy in a food fight. Everything rinses clean with water. Natalie invites me to feel the underside of the cloth, and I do. It is completely dry.

Natalie started with the easy ones. Liquids that are mostly water have high surface tension. That means that the molecules prefer to bond more strongly to each other than to most of the things you might spill them on. A liquid with lower surface tension, like alcohol, won’t bead up on a fabric the way water will; it soaks right in. A bead of water is a molecular huddle, a withdrawal inward, a refusal to join hands with strangers. Confronted with air, the surface of water pulls together powerfully enough to form a weak skin. The insect kingdom has water striders, but no gin striders. At the far high end of the surface-tension spectrum is mercury. Mercury beads up and rolls off pretty much any surface you drop it on without leaving a trace.
§
One of mercury’s qualifications for old-timey thermometerdom—along with staying liquid in extremes of cold and heat—is that it doesn’t wet the inside of the glass. No residue trail! So you can clearly read the temperature.