From T-shirts to carbon fiber, safety advances with speed

From the tip of the fire bottles at the front of Funny Cars to the parachutes that hang beneath their spoilers at the rear, the safety built into these and other drag racing vehicles continues to increase exponentially as e.t.s plummets and speeds soar.

Because of racers (and sometimes in spite of them - protecting the driver never made a car go faster) constant evolution across all areas of the motorsports safety industry allows drivers to survive death-defying 300-mph crashes and race again.

In the earliest days of drag racing, the 1950s, drivers piled into cars clad in what they were wearing minutes earlier when they were bent over the hoods of their cars - usually T-shirts and jeans. Driver apparel has progressed from open-face helmets and leather jackets in the sport's infancy through the aluminized spaceman-looking attire of the 1960s to today's multi-layer custom-fitted suits that offer drivers as much as 40 seconds of protection in a fire.

Nomex, a man-made fabric invented by DuPont, is the best-known and most-used fabric in racing. It isn't a single kind of fabric; there are several variations. Suits also can be made of PBI, which is a Nomex-Kevlar blend; of fire-retardant cotton; of Kynol, a Japanese fabric; of carbon fiber; or of Kevlar.

Driving suits are categorized by their SFI designation - SFI-1, SFI-5, SFI-15, or SFI-20. Funny Car and Federal-Mogul Funny Car drivers wear the thickest suits, 20s. Top Fuel racers are required to wear 15s and not 20s because they sit in front of the engines, but many wear 20s anyway.

SFI-5 suits account for about two-thirds of all drag racing driving suits, and SFI-1s protect a majority of the nation's countless bracket racers. SFI-15 suits have three layers of padding, plus the outer layer, and 20s have another layer. The outer layer generally is woven Nomex, and the inner layer is knit Nomex and is softer and thicker. Simpson dominates the worldwide driving-suit market, selling more than 30,000 of them a year to drivers in drag racing, stock-car racing, sprint-car racing, and Indy-car racing. But whatever they wear, drivers are advised to wear 100-percent cotton or 100-percent wool underneath it - no polyesters. Multiple layers of fabric keep heat away from the skin longer because each layer creates air gaps that must heat up before they transfer heat; a suit worn too tight compresses the air gaps and allows heat to reach the skin faster.

To guide them, drivers follow a standard, SFI Specification 3.2A, which, when attached to the shoulder of their suit, means that what they're wearing meets the mandated SFI spec for their category and has been laboratory tested. The spec gauges the suit's fire-retardant capabilities and is rated according to its ability to provide "thermal protective performance" against both radiant heat and direct flame. It measures the length of time a driver can be exposed to heat before incurring a second-degree (skin-blistering) burn.

Resistance to radiant heat is important because most of the burns drivers suffer come from heat transfer and not from exposure to direct flame. A 3.2A/20 suit gives a driver 40 seconds. At the other end of the spectrum, a 3.2A/1 lasts three seconds before a driver receives second-degree burns.

Thread-heat resistance, zipper-heat resistance, and multiple-layer thermal-shrinkage resistance also are measured, as is the time it takes the material to self-extinguish, the "after-flame time." To pass, the after-flame time for a layer of fabric must be two seconds or less.

Such detailed guidelines are work of SFI technical committees that tap individuals from across the performance industry to establish specifications for roll cages, driver suits, wheels, blower restraints, fuel cells, helmets, and all manner of performance, automotive, specialty, and racing equipment.

SFI, the SEMA Foundation, Inc., spun off from SEMA, the Speed Equipment Manufacturers Association, which was formed in 1963 largely by the manufacturers of racing components to formulate product specs for race-equipment suppliers. Soon their guidelines were accepted and formed a significant portion of sanctioning bodies' rule books.

SFI now operates separately from SEMA, and, among other things, it offers race officials, builders, and racers reliable references for evaluating products. SFI specs are reviewed by a committee of individuals throughout the performance aftermarket industry and are revised to meet changing technology.

Participation is strictly voluntary, but the standards established by SFI have become minimum-requirement rules, adopted by NHRA, IHRA, CART, IRL, USAC, and race sanctioning bodies around the globe. Drag racers walk away from the frightening accidents that they do primarily because NHRA remains on the leading edge on safety issues.

Faster speed but fewer casualties

Dragsters are going faster than ever, but the survival rate is higher than ever. Fewer Funny Car drivers are burned than ever before, and in Top Fuel, break-away chassis, driver tubs, better materials, and evolving standards for chassis builders have motorsports' fastest drivers better protected than ever. Even outside the area of motor racing, the automotive world is growing increasingly aware of the importance of safety concerns; SAE itself is on its way to becoming a repository of design, testing, and safety information for all aspects of the automotive industry.

New lines of helmets made of composite materials are introduced every few years and are subjected to a series of "impact attenuation" tests. Impact attenuation is the ability of a helmet to absorb the energy of an impact, thus reducing the force to the wearer's head. In these tests, helmets are fitted on metal headforms and the helmet/headform assemblies are dropped on steel anvils.

A helmet's hard outer shells provide a driver's primary defense against impact. Race helmets are filled with an energy-absorbing material (EAM) that absorbs impact energy and reduces trauma to the head. The padding, which does not absorb energy, and the energy-absorbing material itself are covered with a fire-retardant lining.

Two SFI specs govern helmets; they are classified as either competition or motorsports. Helmets that meet specs 31.1 and 31.2 undergo fire-resistance testing. The 41.1 and 41.2 helmets are not fire-resistance tested and used primarily by motorcycle racers.

Fire a big threat for Funny Cars

Fire is far less of a danger to drivers than it was in the so-called golden era of the sport, when safety practices were primitive and injuries and even death were not uncommon. Today, Funny Cars, the drag racing vehicles most apt to catch fire, carry more than 20 pounds of fire-fighting agent, either Fire X Plus, Halon, or some other agent. When nozzled properly, with the majority of the agent directed to the engine compartment, where the fire generally begins, drivers almost always escape potentially disastrous fires uninjured.

Fire bottles should always be mounted rearward, with the opening facing the back, to take maximum advantage of the car's positive G-force going downtrack. Strategic placement of the nozzles as high as possible in the engine bay greatly enhances the agent's ability to do its lifesaving work.

Private tests conducted by Firefox show that fire bottles' ability to extinguish flames under old mounting practices was limited because much of the fire-fighting agent simply blew out from under the car. Funny Car drivers also have "fire windows," holes in the dashboard that allow them to see through to the engine compartment and be alerted to the threat of fire in its earliest stages.

To stop from sprints as fast as 330 mph, drivers use parachutes that long have identified drag racing vehicles to casual fans. Parachutes from Bill Simpson, who entered the safety-equipment business not making his famous suits but manufacturing parachutes after he crashed of the end of a California drag strip, and Jim Deist have been safely slowing cars since the 1950s.

Drivers are securely strapped into their cars by three-inch belts in a five-point configuration - one over each shoulder and one around each side of the driver's lap, all anchored by a crotch strap and attached by one of three types of buckles: turn/push, cam lock, or latch/lever. All can be opened in one or two motions.

Seat belts are tested and affixed with SFI certification tags that list the date of manufacture. The useful life of seat belts is just two years because the webbing in the straps degenerates from exposure to the elements and over time. Prolonged exposure to sunlight causes the fibers to deteriorate somewhat and lessens the belts' "restraint integrity."

Webbing can lose as much as half of its strength in one year, so the entire assembly is inspected and re-tagged every two years. Only the original manufacturer can re-web an assembly prior to re-certification, and the webbing typically is made with DuPont Nylon 6-6 or a similar product.

When installing belts in the cockpit, the main rule is to attach the mounting hardware so that it minimizes the bending stress in the fitting as much as possible. The belts should pull from a straight angle against the hardware.

They should be as short as possible to reduce stretching, and their attachment points should afford the best "geometry" (roughly 45 degrees to the ground) in order to minimize movement. They should never rub against any surface that can cause the webbing to fray, and the anchoring mechanisms should be checked often for tightness and for weakening.