Inside an Indianapolis-based factory, dozens of women are pushing and pulling yards of cotton and cloth through rows of sewing machines.

Passersby can barely hear over the revving and almost machine-gun like sound pouring from each machine fastening hundreds of stitches together in mere minutes.

Seaming blocks of fabric together and quilting panels beneath each block, the women are building the most underrated, yet essential piece of equipment required by all NASCAR drivers: the firesuit.

"People don't realize what goes into a firesuit. Each day I tell my employees that we have a chance to save lives with every suit that leaves this building," said John Schneider, president of Impact Racing founded by safety equipment pioneer Bill Simpson.

What started as borax-dipped coveralls in the 1950s has greatly evolved into highly computerized, engineered safety suits made of Nomex and nylon. Since the day NASCAR mandated the use of firesuits, companies from around the globe have been in constant competition to design the next lighter, safer and more comfortable suit to glove the frames of the sport's best drivers.

Mind you, they try to look their best during the process. Drivers do care about the looks of their suits as do their manufacturers, because they are selling a brand. But at the end of the day, safety is the main goal among both parties.

Anatomy of a firesuit

Alpinestars

A Dynamometer machine is a stress test used to measure fabric resistance.

The making of a firesuit is a balance of form and function and it's a process that begins on the computer.

Layouts representing the entire suit are designed on a computer, printed out to scale and cut to size on large panels of Nomex-blended fabric. Once the outer shell of the suit is cut out, the process of quilting the layers together begins.

"The inner layer is the heart of the suit and the outer layer is more or less for sponsors," Schneider said. "The more layers you have the more protection you'll have."

Protection from the fire isn't necessarily the only purpose of the firesuit.

"Everyone thinks that the direct flame causes the problem, but it's the heat transfer," he added. "Let's say you catch on fire. It's not the outside flame that's necessarily harming you although it's the end result of that outside flame. It's the heat transfer going through the suit coming from the flame."

More than that, stored energy is especially harmful.

"The flame is gone but there is this stored energy that can burn you. So you have a driver who has been in a fire and there's no flame but the heat is still there and it will continue to burn until you get the uniform off or get water or take that energy away," Schneider said. "That's where most massive burns come from is the energy locked inside."

The effect of stored energy is a topic of ongoing investigation and research, Schneider added.

"The work never stops on research and development, perfecting your patterns, etc.," he said. "On our end we worry about safety and on the other end they are worried about how they look on camera and in a magazine."

As for the appearance of the suit --- collars, arm gussets, epaulets and quilting -- some of those features were created with function but have since become obsolete. Others have managed to stand the test of time.

Originally, suits were designed with epaulets either on top of the shoulders or on the latissimus dorsi served to pull a driver from a burning or smoking car.

However emergency response experts highly oppose that practice. A driver is not to be moved until experts advise the conditions are safe to prevent neck or spinal cord injuries. But the epaulets still remains on the firesuits and are mostly used for sponsors as billboard space, so to speak.

The best sellers

Alpinestars

P.J. Rashidi, of Alpinestars, helps clothe some of NASCAR's biggest stars.

Dressing the likes of Jeff Gordon and Dale Earnhardt Jr. pays big dividends for these companies by way of brand exposure; therefore they create each suit with style and appearance in mind.

Two-time Cup Series champion Jimmie Johnson's firesuit is custom made and engineered by Alpinestars, an Italian company known for its high-quality suits used in Formula One. The company made its first foray into NASCAR's garage after winning over Kurt Busch in 2003.

The designs, tighter fits and comfort soon became a hot commodity. Johnson followed suit in 2004 and later Gordon and Kyle Busch.

Alpinestars is thought to be the Prada of firesuits. So much so that fans say Kyle Busch looks better in his firesuit than he does in his street clothes. The company has an eye for fashionable detail, each suit is haute couture.

“

If the driver looks better, we look better. If the girls like to check out Kyle more cameras will be on him, which is better for us and his sponsors.

”

P.J. RASHIDI, Alpinestars

"If the driver looks better, we look better. If the girls like to check out Kyle more cameras will be on him, which is better for us and his sponsors," said P.J. Rashidi, racing development for Alpinestars. "Everyone benefits from our work, that's the bottom line."

Some manufacturer will even make the suits tighter in the rear -- unbeknownst to the driver -- in order to benefit the female fan.

"We are sensitive to the female fans and make our drivers look appealing for the female fans. We make tweaks here and there and surprise them. It keeps everyone happy," Rashidi said. "You get comfortable in loose-fitting suits, but form-fitting helps in the car."

Jamie McMurray knows that firesuits have become something more than a protective layer between a driver and a potential fire.

"I really don't take notice if people check me out in my firesuit, but I guess it's really no different, at least for us, than wearing regular street clothes and being checked out," said McMurray, who has worn a few different suit makers during his career and has since settled on the Simpson brand.

Firesuits have graduated from a simple uniform to a piece of fashionable self-expression. From the pioneering designs of Simpson to the most recent fittings developed by adidas, dozens of companies are making their mark in the game.

The sponsors aren't the only names slapped on the front of these walking shiny billboards. If you look around the shoulders of the driver you can see who he wears, much like if you checked out the back pockets of his jeans.

Earnhardt made a splash this season when he brought a mainstream sports-wear company to the game after donning the iconic three stripes of adidas. It was a partnership between two powerhouse brands and a way for Earnhardt to find a suit that didn't creep up his leg while driving or shrink at the cleaners.

'Not a beauty contest'

Autostock

Clint Bowyer prefers comfort when sitting in his firesuit for hours at a time.

Contrary to how much a driver is willing to admit, they are particular about their firesuits.

"This is not a beauty contest," said Juan Montoya, who is outfitted by Impact Racing. "I'm already taken so it doesn't matter."

But to listen to the former Formula One driver turned Cup racer, you realize he has a strong influence over what goes into his threads. All the drivers do.

"For me it is how the suit is made. You know what you like," Montoya said. "For me I don't use pockets. And I don't like the NASCAR way with the suit over the boot. Everyone tucks theirs in but they have an extra layer that goes outside, I don't like that. And the stitching needs to go forward. The sides need to be forward so it's not on your ribs."

And in case you didn't notice, Montoya has more room in the rear of his suit than the average driver.

"Yeah, it's comfortable," he said. "It needs to be baggy when you do the butt so it doesn't squeeze my ..."

Message received, loud and clear.

But Clint Bowyer knows how extra material can bunch up and cause problems, restrict movement or create discomfort. The safety belts which strap a driver into his car are tight and don't allow for adjustments, he said.

Meaning, if you get a wedge in your shorts ...

"You just have to tough it out for 500 miles," Bowyer said with a laugh.

So, if drivers are particular about fit and styles, do they grade other drivers? A rundown of "Who Wore it Best?" in the garage.

"We don't sit around like a pack of women looking at each others' firesuits," said Bowyer, who is outfitted by Simpson. "But everyone has different suits and some are built a little differently."

Added Montoya: "I think the only time I heard drivers talk about other drivers' suits is when Jacques Villeneuve showed up because he's so little, but his suit was like four sizes too big; mine is only two sizes."

"That's why comfort is so important and for me it has to breathe. Your suit helps keep you cool while inside the hot car," Bowyer said.

Firesuits are constantly changing with the body of the driver. If Johnson gains muscle mass, the suit gets altered. If he loses any significant amount of weight, Alpinestars is on a plane to Charlotte, N.C., with new gear.

"Their attention to detail has been really, really amazing. They've been willing to develop and make stuff more comfortable and safer at the same time. So I really commend Alpinestars for the job that they've done and always being so flexible and making things look good and different," Johnson said.

But at the end of the day, Johnson and most drivers will go with whichever company is displaying the latest and safest in fire-proof technologies.

"I have a relationship with Alpinestars. But I want to make sure that I'm not under a contract with any of the suppliers, because I want to wear what is the safest stuff that can be offered to any driver," Johnson added.

If you look closely, you'll notice the difference in an Alpinestars suits compared to an Impact Racing, adidas, Sparco or Simpson brand product.

The detail is in the collar.

"In our suits the collar is a bit higher and that's a safety measure. These guys are not required to wear socks over their face so the neck is exposed when the head leans forward," Rashidi explained. "The collar is for more coverage."

Before the 1970s, drivers wore nothing to protect their necks. In fact, they wore nothing tougher than a cotton T-shirt and a pair of dungarees. So it should come as no surprise that many talented, smart drivers paid the price for their lack of safety gear.

In 1959, Bobby Allison was running a modified stock-car race at Dixie Speedway when on a hurried fuel stop gas was spilled into his car. Flames ignited throughout the cockpit. At that time, he was wearing a T-shirt that said "Save with Vigorlube."

Alpinestars

Nothing at Alpinestars passes without first undergoing the fireproof test.

"The part that said 'Save with' was kind of like a decal ... those words were burned right into my back," recalled Allison in an interview for Bill Simpson's book Racing Safely Living Dangerously.

Drivers thought they were being safe when they began wearing cotton driving suits dipped into a mixture of Boraxo and water just before climbing into the car. It wasn't entirely effective. And Allison said he wore the dipped suits because they looked nice, not because he thought they were safe.

Nearing the end of the 1960s, the motorsports industry realized it needed to make a concerted effort toward engineering a fire-retardant suit. Simpson used his connections with NASA and procured some Nomex-blended material, which would come to revolutionize the driving suit.

"The material was filament Nomex, and I was the first person to make a racing suit out of it. I took an old cotton driver's uniform and cut it apart; from there I made a pattern, put my ever-expanding sewing skills to work and stitched up a suit out of Nomex," Simpson recalled in his book.

The suit debuted at the Indianapolis 500 in the late 1960s and expanded to other series including drag racing and NASCAR. But the work didn't stop there.

"The constant battle you faced is that drivers' didn't want to wear them, because they were too hot. I always said, 'hey if you have a 1000-degree fire it's going to get a whole lot hotter," said John Schneider, who works with Simpson on new technologies for Impact Racing.

"And back then drivers didn't want to buy suits. They wanted to spend all their money on going fast. Now you just don't even see a driver step inside a car without one."

An ongoing evolution, the firesuit will continue to be an essential piece of equipment and even a style statement for drivers as long as the sport exists.

But you can count on just a handful of things that will remain the same no matter the decade or the driver in it.

"Ah, it's a question that everyone wants to ask," McMurray said. "You have to pick and choose your battle. If there are 40 laps left and you think you can hold it, you just tough it out. If you are halfway and it's been a long race already, then you just go.

"It's part of it. Everyone does it."