A racing suit or racing overalls, often referred to as a fire suit due to its fire retardant properties, is clothing such as overalls worn in various forms of auto racing by racing drivers, crew members who work on the vehicles during races, track safety workers or marshals, and in some series commentators at the event.
In the early days of racing, most racing series had no mandated uniforms. Beginning in the 1950s and 1960s, specialized racing suits were designed to optimize driver temperature via heat transfer, and later to protect drivers from fire. By 1967, the majority of competitors in Formula One, NASCAR, the National Hot Rod Association (NHRA), United States Auto Club (USAC), and Champ Car (the predecessor to modern IndyCar) began wearing specialized fire suits. Most modern suits use Nomex, a material developed in the 1960s around the time fire suits emerged. The suits are also known for prominently displaying driver sponsors.
Design and use
A racing suit is designed to cover the entire body of a driver, crew member, or marshall, including long sleeves and long pants legs. Typical driver suits are one-piece overalls, similar in appearance to a boilersuit. Other fire suits are two piece, consisting of a "jacket" and pants. The suits consist of a single or multiple layers of fire-retardant material. The suits also have special epaulettes or yokes on the shoulder area that act as "handles" in order to lift a driver strapped to a racing seat out of a vehicle. This is mandated under Fédération Internationale de l'Automobile (FIA) safety standards.
Most suits use fabric made of Nomex, a synthetic material produced by DuPont that retains its fire-retardant properties with time and use. Other suits consist of cotton treated with Proban, a chemical manufactured by Rhodia, or other substances. These suits can lose their fire-resistant properties over time, particularly after washing. Other suits are made of Kevlar, polybenzimidazole fiber (PBI), or carbon fibers, but are less widely used due to lack of comfort and color variety. Newer suits, such as those produced by Sparco, have inner liners treated with menthol to create a cooling sensation and fight odor. Additional accessories, including fire-resistant long underwear, gloves, shoes, and balaclava-like face masks or "head socks" are also worn.
When Nomex material is exposed to flame, instead of burning or melting it develops a carbon char. The char thickens the section of fiber exposed to the flame, preventing the spread of the fire to the rest of the suit and inhibiting the transfer of heat to the wearer of the garment. CarbonX is a different fabric for fire suits made of oxidized polyacrylonitrile (a precursor to carbon fiber). It is created by heating material until it oxidizes and chars, with the finished product able to last for two minutes exposed to fire. It is frequently used for racing undergarments and gloves. Using multiple layers of the material, and quilting of the fabric, meanwhile, create pockets of air which further insulate the wearer from heat.
The suits are not entirely fireproof, but rather fire retardant for a period of time, allowing an individual to escape an incident or be rescued with minimal injury. Bill Simpson, an innovator in racing safety, estimated in 1993 that a person has "20 to 30 seconds" before a fire suit begins to burn. The mandated minimum level of protection for uniforms in different racing series varies, as does the minimum standard for drivers, crew members, and officials. In the NHRA drag racing series, for example, suits are designed to last 30 to 40 seconds before the wearer suffers second degree burns. This is a higher benchmark than that of most other series, due to the high risk of fire from nitromethane and alcohol-fueled cars. SFI Foundation, Inc., formerly part of SEMA, dictates the suit fire protection standards for numerous sanctioning bodies particularly in the United States, including NASCAR, IndyCar, the NHRA, the Sports Car Club of America (SCCA), and the United States Auto Club (USAC). The FIA determines the standards for most of its series such as Formula One and the FIA World Endurance Championship, excluding the standards of its drag racing competition which are determined by SFI. SFI and FIA standards are used by other organizations outside their jurisdiction, such as the Confederation of Australian Motor Sport (CAMS).